Type: string
Default: null
Importance: high
Dynamic update: per-broker

Listeners to publish to ZooKeeper for clients to use, if different than the listeners config property. In IaaS environments, this may need to be different from the interface to which the broker binds. If this is not set, the value for listeners will be used. Unlike listeners, it is not valid to advertise the 0.0.0.0 meta-address. Also unlike listeners, there can be duplicated ports in this property, so that one listener can be configured to advertise another listener’s address. This can be useful in some cases where external load balancers are used.

Type: boolean
Default: true
Importance: high
Dynamic update: read-only

Enable auto creation of topic on the server.

Type: boolean
Default: true
Importance: high
Dynamic update: read-only

Enables auto leader balancing. A background thread checks the distribution of partition leaders at regular intervals, configurable by leader.imbalance.check.interval.seconds. If the leader imbalance exceeds leader.imbalance.per.broker.percentage, leader rebalance to the preferred leader for partitions is triggered.

Type: int
Default: 10
Valid Values: [1,…​]
Importance: high
Dynamic update: cluster-wide

The number of threads to use for various background processing tasks.

Type: int
Default: -1
Importance: high
Dynamic update: read-only

The broker id for this server. If unset, a unique broker id will be generated.To avoid conflicts between zookeeper generated broker id’s and user configured broker id’s, generated broker ids start from reserved.broker.max.id + 1.

Type: string
Default: producer
Importance: high
Dynamic update: cluster-wide

Specify the final compression type for a given topic. This configuration accepts the standard compression codecs ('gzip', 'snappy', 'lz4', 'zstd'). It additionally accepts 'uncompressed' which is equivalent to no compression; and 'producer' which means retain the original compression codec set by the producer.

Type: string
Default: null
Importance: high
Dynamic update: read-only

Name of listener used for communication between controller and brokers. Broker will use the control.plane.listener.name to locate the endpoint in listeners list, to listen for connections from the controller. For example, if a broker’s config is : listeners = INTERNAL://192.1.1.8:9092, EXTERNAL://10.1.1.5:9093, CONTROLLER://192.1.1.8:9094 listener.security.protocol.map = INTERNAL:PLAINTEXT, EXTERNAL:SSL, CONTROLLER:SSL control.plane.listener.name = CONTROLLER On startup, the broker will start listening on "192.1.1.8:9094" with security protocol "SSL". On controller side, when it discovers a broker’s published endpoints through zookeeper, it will use the control.plane.listener.name to find the endpoint, which it will use to establish connection to the broker. For example, if the broker’s published endpoints on zookeeper are : "endpoints" : ["INTERNAL://broker1.example.com:9092","EXTERNAL://broker1.example.com:9093","CONTROLLER://broker1.example.com:9094"] and the controller’s config is : listener.security.protocol.map = INTERNAL:PLAINTEXT, EXTERNAL:SSL, CONTROLLER:SSL control.plane.listener.name = CONTROLLER then controller will use "broker1.example.com:9094" with security protocol "SSL" to connect to the broker. If not explicitly configured, the default value will be null and there will be no dedicated endpoints for controller connections.

Type: string
Default: null
Importance: high
Dynamic update: read-only

A comma-separated list of the names of the listeners used by the controller. This is required if running in KRaft mode. When communicating with the controller quorum, the broker will always use the first listener in this list. Note: The ZK-based controller should not set this configuration.

Type: int
Default: 1000 (1 second)
Importance: high
Dynamic update: read-only

Maximum time in milliseconds before starting new elections. This is used in the binary exponential backoff mechanism that helps prevent gridlocked elections.

Type: int
Default: 1000 (1 second)
Importance: high
Dynamic update: read-only

Maximum time in milliseconds to wait without being able to fetch from the leader before triggering a new election.

Type: int
Default: 2000 (2 seconds)
Importance: high
Dynamic update: read-only

Maximum time without a successful fetch from the current leader before becoming a candidate and triggering a election for voters; Maximum time without receiving fetch from a majority of the quorum before asking around to see if there’s a new epoch for leader.

Type: list
Default: ""
Valid Values: non-empty list
Importance: high
Dynamic update: read-only

Map of id/endpoint information for the set of voters in a comma-separated list of {id}@{host}:{port} entries. For example: 1@localhost:9092,2@localhost:9093,3@localhost:9094.

Type: boolean
Default: true
Importance: high
Dynamic update: read-only

Enables delete topic. Delete topic through the admin tool will have no effect if this config is turned off.

Type: long
Default: 300
Valid Values: [1,…​]
Importance: high
Dynamic update: read-only

The frequency with which the partition rebalance check is triggered by the controller.

Type: int
Default: 10
Importance: high
Dynamic update: read-only

The ratio of leader imbalance allowed per broker. The controller would trigger a leader balance if it goes above this value per broker. The value is specified in percentage.

Type: string
Default: PLAINTEXT://:9092
Importance: high
Dynamic update: per-broker

Listener List - Comma-separated list of URIs we will listen on and the listener names. If the listener name is not a security protocol, listener.security.protocol.map must also be set. Listener names and port numbers must be unique. Specify hostname as 0.0.0.0 to bind to all interfaces. Leave hostname empty to bind to default interface. Examples of legal listener lists: PLAINTEXT://myhost:9092,SSL://:9091 CLIENT://0.0.0.0:9092,REPLICATION://localhost:9093.

Type: string
Default: /tmp/kafka-logs
Importance: high
Dynamic update: read-only

The directory in which the log data is kept (supplemental for log.dirs property).

Type: string
Default: null
Importance: high
Dynamic update: read-only

The directories in which the log data is kept. If not set, the value in log.dir is used.

Type: long
Default: 9223372036854775807
Valid Values: [1,…​]
Importance: high
Dynamic update: cluster-wide

The number of messages accumulated on a log partition before messages are flushed to disk.

Type: long
Default: null
Importance: high
Dynamic update: cluster-wide

The maximum time in ms that a message in any topic is kept in memory before flushed to disk. If not set, the value in log.flush.scheduler.interval.ms is used.

Type: int
Default: 60000 (1 minute)
Valid Values: [0,…​]
Importance: high
Dynamic update: read-only

The frequency with which we update the persistent record of the last flush which acts as the log recovery point.

Type: long
Default: 9223372036854775807
Importance: high
Dynamic update: read-only

The frequency in ms that the log flusher checks whether any log needs to be flushed to disk.

Type: int
Default: 60000 (1 minute)
Valid Values: [0,…​]
Importance: high
Dynamic update: read-only

The frequency with which we update the persistent record of log start offset.

Type: long
Default: -1
Importance: high
Dynamic update: cluster-wide

The maximum size of the log before deleting it.

Type: int
Default: 168
Importance: high
Dynamic update: read-only

The number of hours to keep a log file before deleting it (in hours), tertiary to log.retention.ms property.

Type: int
Default: null
Importance: high
Dynamic update: read-only

The number of minutes to keep a log file before deleting it (in minutes), secondary to log.retention.ms property. If not set, the value in log.retention.hours is used.

Type: long
Default: null
Importance: high
Dynamic update: cluster-wide

The number of milliseconds to keep a log file before deleting it (in milliseconds), If not set, the value in log.retention.minutes is used. If set to -1, no time limit is applied.

Type: int
Default: 168
Valid Values: [1,…​]
Importance: high
Dynamic update: read-only

The maximum time before a new log segment is rolled out (in hours), secondary to log.roll.ms property.

Type: int
Default: 0
Valid Values: [0,…​]
Importance: high
Dynamic update: read-only

The maximum jitter to subtract from logRollTimeMillis (in hours), secondary to log.roll.jitter.ms property.

Type: long
Default: null
Importance: high
Dynamic update: cluster-wide

The maximum jitter to subtract from logRollTimeMillis (in milliseconds). If not set, the value in log.roll.jitter.hours is used.

Type: long
Default: null
Importance: high
Dynamic update: cluster-wide

The maximum time before a new log segment is rolled out (in milliseconds). If not set, the value in log.roll.hours is used.

Type: int
Default: 1073741824 (1 gibibyte)
Valid Values: [14,…​]
Importance: high
Dynamic update: cluster-wide

The maximum size of a single log file.

Type: long
Default: 60000 (1 minute)
Valid Values: [0,…​]
Importance: high
Dynamic update: cluster-wide

The amount of time to wait before deleting a file from the filesystem.

Type: int
Default: 1048588
Valid Values: [0,…​]
Importance: high
Dynamic update: cluster-wide

The largest record batch size allowed by Kafka (after compression if compression is enabled). If this is increased and there are consumers older than 0.10.2, the consumers' fetch size must also be increased so that they can fetch record batches this large. In the latest message format version, records are always grouped into batches for efficiency. In previous message format versions, uncompressed records are not grouped into batches and this limit only applies to a single record in that case.This can be set per topic with the topic level max.message.bytes config.

Type: string
Default: null
Importance: high
Dynamic update: read-only

This configuration determines where we put the metadata log for clusters in KRaft mode. If it is not set, the metadata log is placed in the first log directory from log.dirs.

Type: long
Default: 20971520
Valid Values: [1,…​]
Importance: high
Dynamic update: read-only

This is the maximum number of bytes in the log between the latest snapshot and the high-watermark needed before generating a new snapshot.

Type: int
Default: 1073741824 (1 gibibyte)
Valid Values: [12,…​]
Importance: high
Dynamic update: read-only

The maximum size of a single metadata log file.

Type: long
Default: 604800000 (7 days)
Importance: high
Dynamic update: read-only

The maximum time before a new metadata log file is rolled out (in milliseconds).

Type: long
Default: -1
Importance: high
Dynamic update: read-only

The maximum combined size of the metadata log and snapshots before deleting old snapshots and log files. Since at least one snapshot must exist before any logs can be deleted, this is a soft limit.

Type: long
Default: 604800000 (7 days)
Importance: high
Dynamic update: read-only

The number of milliseconds to keep a metadata log file or snapshot before deleting it. Since at least one snapshot must exist before any logs can be deleted, this is a soft limit.

Type: int
Default: 1
Valid Values: [1,…​]
Importance: high
Dynamic update: cluster-wide

When a producer sets acks to "all" (or "-1"), min.insync.replicas specifies the minimum number of replicas that must acknowledge a write for the write to be considered successful. If this minimum cannot be met, then the producer will raise an exception (either NotEnoughReplicas or NotEnoughReplicasAfterAppend). When used together, min.insync.replicas and acks allow you to enforce greater durability guarantees. A typical scenario would be to create a topic with a replication factor of 3, set min.insync.replicas to 2, and produce with acks of "all". This will ensure that the producer raises an exception if a majority of replicas do not receive a write.

Type: int
Default: -1
Importance: high
Dynamic update: read-only

The node ID associated with the roles this process is playing when process.roles is non-empty. This is required configuration when running in KRaft mode.

Type: int
Default: 8
Valid Values: [1,…​]
Importance: high
Dynamic update: cluster-wide

The number of threads that the server uses for processing requests, which may include disk I/O.

Type: int
Default: 3
Valid Values: [1,…​]
Importance: high
Dynamic update: cluster-wide

The number of threads that the server uses for receiving requests from the network and sending responses to the network.

Type: int
Default: 1
Valid Values: [1,…​]
Importance: high
Dynamic update: cluster-wide

The number of threads per data directory to be used for log recovery at startup and flushing at shutdown.

Type: int
Default: null
Importance: high
Dynamic update: read-only

The number of threads that can move replicas between log directories, which may include disk I/O.

Type: int
Default: 1
Importance: high
Dynamic update: cluster-wide

Number of fetcher threads used to replicate messages from a source broker. Increasing this value can increase the degree of I/O parallelism in the follower broker.

Type: int
Default: 4096 (4 kibibytes)
Importance: high
Dynamic update: read-only

The maximum size for a metadata entry associated with an offset commit.

Type: short
Default: -1
Importance: high
Dynamic update: read-only

The required acks before the commit can be accepted. In general, the default (-1) should not be overridden.

Type: int
Default: 5000 (5 seconds)
Valid Values: [1,…​]
Importance: high
Dynamic update: read-only

Offset commit will be delayed until all replicas for the offsets topic receive the commit or this timeout is reached. This is similar to the producer request timeout.

Type: int
Default: 5242880
Valid Values: [1,…​]
Importance: high
Dynamic update: read-only

Batch size for reading from the offsets segments when loading offsets into the cache (soft-limit, overridden if records are too large).

Type: long
Default: 600000 (10 minutes)
Valid Values: [1,…​]
Importance: high
Dynamic update: read-only

Frequency at which to check for stale offsets.

Type: int
Default: 10080
Valid Values: [1,…​]
Importance: high
Dynamic update: read-only

After a consumer group loses all its consumers (i.e. becomes empty) its offsets will be kept for this retention period before getting discarded. For standalone consumers (using manual assignment), offsets will be expired after the time of last commit plus this retention period.

Type: int
Default: 0
Importance: high
Dynamic update: read-only

Compression codec for the offsets topic - compression may be used to achieve "atomic" commits.

Type: int
Default: 50
Valid Values: [1,…​]
Importance: high
Dynamic update: read-only

The number of partitions for the offset commit topic (should not change after deployment).

Type: short
Default: 3
Valid Values: [1,…​]
Importance: high
Dynamic update: read-only

The replication factor for the offsets topic (set higher to ensure availability). Internal topic creation will fail until the cluster size meets this replication factor requirement.

Type: int
Default: 104857600 (100 mebibytes)
Valid Values: [1,…​]
Importance: high
Dynamic update: read-only

The offsets topic segment bytes should be kept relatively small in order to facilitate faster log compaction and cache loads.

Type: list
Default: ""
Valid Values: [broker, controller]
Importance: high
Dynamic update: read-only

The roles that this process plays: 'broker', 'controller', or 'broker,controller' if it is both. This configuration is only applicable for clusters in KRaft (Kafka Raft) mode (instead of ZooKeeper). Leave this config undefined or empty for Zookeeper clusters.

Type: int
Default: 500
Valid Values: [1,…​]
Importance: high
Dynamic update: read-only

The number of queued requests allowed for data-plane, before blocking the network threads.

Type: int
Default: 1
Importance: high
Dynamic update: read-only

Minimum bytes expected for each fetch response. If not enough bytes, wait up to replica.fetch.wait.max.ms (broker config).

Type: int
Default: 500
Importance: high
Dynamic update: read-only

The maximum wait time for each fetcher request issued by follower replicas. This value should always be less than the replica.lag.time.max.ms at all times to prevent frequent shrinking of ISR for low throughput topics.

Type: long
Default: 5000 (5 seconds)
Importance: high
Dynamic update: read-only

The frequency with which the high watermark is saved out to disk.

Type: long
Default: 30000 (30 seconds)
Importance: high
Dynamic update: read-only

If a follower hasn’t sent any fetch requests or hasn’t consumed up to the leaders log end offset for at least this time, the leader will remove the follower from isr.

Type: int
Default: 65536 (64 kibibytes)
Importance: high
Dynamic update: read-only

The socket receive buffer for network requests.

Type: int
Default: 30000 (30 seconds)
Importance: high
Dynamic update: read-only

The socket timeout for network requests. Its value should be at least replica.fetch.wait.max.ms.

Type: int
Default: 30000 (30 seconds)
Importance: high
Dynamic update: read-only

The configuration controls the maximum amount of time the client will wait for the response of a request. If the response is not received before the timeout elapses the client will resend the request if necessary or fail the request if retries are exhausted.

Type: string
Default: GSSAPI
Importance: high
Dynamic update: read-only

SASL mechanism used for communication with controllers. Default is GSSAPI.

Type: int
Default: 102400 (100 kibibytes)
Importance: high
Dynamic update: read-only

The SO_RCVBUF buffer of the socket server sockets. If the value is -1, the OS default will be used.

Type: int
Default: 104857600 (100 mebibytes)
Valid Values: [1,…​]
Importance: high
Dynamic update: read-only

The maximum number of bytes in a socket request.

Type: int
Default: 102400 (100 kibibytes)
Importance: high
Dynamic update: read-only

The SO_SNDBUF buffer of the socket server sockets. If the value is -1, the OS default will be used.

Type: int
Default: 900000 (15 minutes)
Valid Values: [1,…​]
Importance: high
Dynamic update: read-only

The maximum allowed timeout for transactions. If a client’s requested transaction time exceed this, then the broker will return an error in InitProducerIdRequest. This prevents a client from too large of a timeout, which can stall consumers reading from topics included in the transaction.

Type: int
Default: 5242880
Valid Values: [1,…​]
Importance: high
Dynamic update: read-only

Batch size for reading from the transaction log segments when loading producer ids and transactions into the cache (soft-limit, overridden if records are too large).

Type: int
Default: 2
Valid Values: [1,…​]
Importance: high
Dynamic update: read-only

Overridden min.insync.replicas config for the transaction topic.

Type: int
Default: 50
Valid Values: [1,…​]
Importance: high
Dynamic update: read-only

The number of partitions for the transaction topic (should not change after deployment).

Type: short
Default: 3
Valid Values: [1,…​]
Importance: high
Dynamic update: read-only

The replication factor for the transaction topic (set higher to ensure availability). Internal topic creation will fail until the cluster size meets this replication factor requirement.

Type: int
Default: 104857600 (100 mebibytes)
Valid Values: [1,…​]
Importance: high
Dynamic update: read-only

The transaction topic segment bytes should be kept relatively small in order to facilitate faster log compaction and cache loads.

Type: int
Default: 604800000 (7 days)
Valid Values: [1,…​]
Importance: high
Dynamic update: read-only

The time in ms that the transaction coordinator will wait without receiving any transaction status updates for the current transaction before expiring its transactional id. This setting also influences producer id expiration - producer ids are expired once this time has elapsed after the last write with the given producer id. Note that producer ids may expire sooner if the last write from the producer id is deleted due to the topic’s retention settings.

Type: boolean
Default: false
Importance: high
Dynamic update: cluster-wide

Indicates whether to enable replicas not in the ISR set to be elected as leader as a last resort, even though doing so may result in data loss.

Type: string
Default: null
Importance: high
Dynamic update: read-only

Specifies the ZooKeeper connection string in the form hostname:port where host and port are the host and port of a ZooKeeper server. To allow connecting through other ZooKeeper nodes when that ZooKeeper machine is down you can also specify multiple hosts in the form hostname1:port1,hostname2:port2,hostname3:port3. The server can also have a ZooKeeper chroot path as part of its ZooKeeper connection string which puts its data under some path in the global ZooKeeper namespace. For example to give a chroot path of /chroot/path you would give the connection string as hostname1:port1,hostname2:port2,hostname3:port3/chroot/path.

Type: int
Default: null
Importance: high
Dynamic update: read-only

The max time that the client waits to establish a connection to zookeeper. If not set, the value in zookeeper.session.timeout.ms is used.

Type: int
Default: 10
Valid Values: [1,…​]
Importance: high
Dynamic update: read-only

The maximum number of unacknowledged requests the client will send to Zookeeper before blocking.

Type: int
Default: 18000 (18 seconds)
Importance: high
Dynamic update: read-only

Zookeeper session timeout.

Type: boolean
Default: false
Importance: high
Dynamic update: read-only

Set client to use secure ACLs.

Type: int
Default: 2000 (2 seconds)
Importance: medium
Dynamic update: read-only

The length of time in milliseconds between broker heartbeats. Used when running in KRaft mode.

Type: boolean
Default: true
Importance: medium
Dynamic update: read-only

Enable automatic broker id generation on the server. When enabled the value configured for reserved.broker.max.id should be reviewed.

Type: string
Default: null
Importance: medium
Dynamic update: read-only

Rack of the broker. This will be used in rack aware replication assignment for fault tolerance. Examples: RACK1, us-east-1d.

Type: int
Default: 9000 (9 seconds)
Importance: medium
Dynamic update: read-only

The length of time in milliseconds that a broker lease lasts if no heartbeats are made. Used when running in KRaft mode.

Type: long
Default: 600000 (10 minutes)
Importance: medium
Dynamic update: read-only

Idle connections timeout: the server socket processor threads close the connections that idle more than this.

Type: long
Default: 0
Importance: medium
Dynamic update: read-only

When explicitly set to a positive number (the default is 0, not a positive number), a session lifetime that will not exceed the configured value will be communicated to v2.2.0 or later clients when they authenticate. The broker will disconnect any such connection that is not re-authenticated within the session lifetime and that is then subsequently used for any purpose other than re-authentication. Configuration names can optionally be prefixed with listener prefix and SASL mechanism name in lower-case. For example, listener.name.sasl_ssl.oauthbearer.connections.max.reauth.ms=3600000.

Type: boolean
Default: true
Importance: medium
Dynamic update: read-only

Enable controlled shutdown of the server.

Type: int
Default: 3
Importance: medium
Dynamic update: read-only

Controlled shutdown can fail for multiple reasons. This determines the number of retries when such failure happens.

Type: long
Default: 5000 (5 seconds)
Importance: medium
Dynamic update: read-only

Before each retry, the system needs time to recover from the state that caused the previous failure (Controller fail over, replica lag etc). This config determines the amount of time to wait before retrying.

Type: int
Default: 25
Importance: medium
Dynamic update: read-only

The duration in milliseconds that the leader will wait for writes to accumulate before flushing them to disk.

Type: int
Default: 2000 (2 seconds)
Importance: medium
Dynamic update: read-only

The configuration controls the maximum amount of time the client will wait for the response of a request. If the response is not received before the timeout elapses the client will resend the request if necessary or fail the request if retries are exhausted.

Type: int
Default: 30000 (30 seconds)
Importance: medium
Dynamic update: read-only

The socket timeout for controller-to-broker channels.

Type: int
Default: 1
Importance: medium
Dynamic update: read-only

The default replication factors for automatically created topics.

Type: long
Default: 86400000 (1 day)
Valid Values: [1,…​]
Importance: medium
Dynamic update: read-only

The token validity time in miliseconds before the token needs to be renewed. Default value 1 day.

Type: password
Default: null
Importance: medium
Dynamic update: read-only

DEPRECATED: An alias for delegation.token.secret.key, which should be used instead of this config.

Type: long
Default: 604800000 (7 days)
Valid Values: [1,…​]
Importance: medium
Dynamic update: read-only

The token has a maximum lifetime beyond which it cannot be renewed anymore. Default value 7 days.

Type: password
Default: null
Importance: medium
Dynamic update: read-only

Secret key to generate and verify delegation tokens. The same key must be configured across all the brokers. If the key is not set or set to empty string, brokers will disable the delegation token support.

Type: int
Default: 1
Importance: medium
Dynamic update: read-only

The purge interval (in number of requests) of the delete records request purgatory.

Type: int
Default: 57671680 (55 mebibytes)
Valid Values: [1024,…​]
Importance: medium
Dynamic update: read-only

The maximum number of bytes we will return for a fetch request. Must be at least 1024.

Type: int
Default: 1000
Importance: medium
Dynamic update: read-only

The purge interval (in number of requests) of the fetch request purgatory.

Type: int
Default: 3000 (3 seconds)
Importance: medium
Dynamic update: read-only

The amount of time the group coordinator will wait for more consumers to join a new group before performing the first rebalance. A longer delay means potentially fewer rebalances, but increases the time until processing begins.

Type: int
Default: 1800000 (30 minutes)
Importance: medium
Dynamic update: read-only

The maximum allowed session timeout for registered consumers. Longer timeouts give consumers more time to process messages in between heartbeats at the cost of a longer time to detect failures.

Type: int
Default: 2147483647
Valid Values: [1,…​]
Importance: medium
Dynamic update: read-only

The maximum number of consumers that a single consumer group can accommodate.

Type: int
Default: 6000 (6 seconds)
Importance: medium
Dynamic update: read-only

The minimum allowed session timeout for registered consumers. Shorter timeouts result in quicker failure detection at the cost of more frequent consumer heartbeating, which can overwhelm broker resources.

Type: int
Default: 60000 (1 minute)
Importance: medium
Dynamic update: read-only

When initially registering with the controller quorum, the number of milliseconds to wait before declaring failure and exiting the broker process.

Type: string
Default: null
Importance: medium
Dynamic update: read-only

Name of listener used for communication between brokers. If this is unset, the listener name is defined by security.inter.broker.protocol. It is an error to set this and security.inter.broker.protocol properties at the same time.

Type: string
Default: 3.2-IV0
Valid Values: [0.8.0, 0.8.1, 0.8.2, 0.9.0, 0.10.0-IV0, 0.10.0-IV1, 0.10.1-IV0, 0.10.1-IV1, 0.10.1-IV2, 0.10.2-IV0, 0.11.0-IV0, 0.11.0-IV1, 0.11.0-IV2, 1.0-IV0, 1.1-IV0, 2.0-IV0, 2.0-IV1, 2.1-IV0, 2.1-IV1, 2.1-IV2, 2.2-IV0, 2.2-IV1, 2.3-IV0, 2.3-IV1, 2.4-IV0, 2.4-IV1, 2.5-IV0, 2.6-IV0, 2.7-IV0, 2.7-IV1, 2.7-IV2, 2.8-IV0, 2.8-IV1, 3.0-IV0, 3.0-IV1, 3.1-IV0, 3.2-IV0]
Importance: medium
Dynamic update: read-only

Specify which version of the inter-broker protocol will be used. This is typically bumped after all brokers were upgraded to a new version. Example of some valid values are: 0.8.0, 0.8.1, 0.8.1.1, 0.8.2, 0.8.2.0, 0.8.2.1, 0.9.0.0, 0.9.0.1 Check ApiVersion for the full list.

Type: long
Default: 15000 (15 seconds)
Valid Values: [0,…​]
Importance: medium
Dynamic update: cluster-wide

The amount of time to sleep when there are no logs to clean.

Type: long
Default: 134217728
Importance: medium
Dynamic update: cluster-wide

The total memory used for log deduplication across all cleaner threads.

Type: long
Default: 86400000 (1 day)
Importance: medium
Dynamic update: cluster-wide

The amount of time to retain delete tombstone markers for log compacted topics. This setting also gives a bound on the time in which a consumer must complete a read if they begin from offset 0 to ensure that they get a valid snapshot of the final stage (otherwise delete tombstones may be collected before they complete their scan).

Type: boolean
Default: true
Importance: medium
Dynamic update: read-only

Enable the log cleaner process to run on the server. Should be enabled if using any topics with a cleanup.policy=compact including the internal offsets topic. If disabled those topics will not be compacted and continually grow in size.

Type: double
Default: 0.9
Importance: medium
Dynamic update: cluster-wide

Log cleaner dedupe buffer load factor. The percentage full the dedupe buffer can become. A higher value will allow more log to be cleaned at once but will lead to more hash collisions.

Type: int
Default: 524288
Valid Values: [0,…​]
Importance: medium
Dynamic update: cluster-wide

The total memory used for log cleaner I/O buffers across all cleaner threads.

Type: double
Default: 1.7976931348623157E308
Importance: medium
Dynamic update: cluster-wide

The log cleaner will be throttled so that the sum of its read and write i/o will be less than this value on average.

Type: long
Default: 9223372036854775807
Importance: medium
Dynamic update: cluster-wide

The maximum time a message will remain ineligible for compaction in the log. Only applicable for logs that are being compacted.

Type: double
Default: 0.5
Importance: medium
Dynamic update: cluster-wide

The minimum ratio of dirty log to total log for a log to eligible for cleaning. If the log.cleaner.max.compaction.lag.ms or the log.cleaner.min.compaction.lag.ms configurations are also specified, then the log compactor considers the log eligible for compaction as soon as either: (i) the dirty ratio threshold has been met and the log has had dirty (uncompacted) records for at least the log.cleaner.min.compaction.lag.ms duration, or (ii) if the log has had dirty (uncompacted) records for at most the log.cleaner.max.compaction.lag.ms period.

Type: long
Default: 0
Importance: medium
Dynamic update: cluster-wide

The minimum time a message will remain uncompacted in the log. Only applicable for logs that are being compacted.

Type: int
Default: 1
Valid Values: [0,…​]
Importance: medium
Dynamic update: cluster-wide

The number of background threads to use for log cleaning.

Type: list
Default: delete
Valid Values: [compact, delete]
Importance: medium
Dynamic update: cluster-wide

The default cleanup policy for segments beyond the retention window. A comma separated list of valid policies. Valid policies are: "delete" and "compact".

Type: int
Default: 4096 (4 kibibytes)
Valid Values: [0,…​]
Importance: medium
Dynamic update: cluster-wide

The interval with which we add an entry to the offset index.

Type: int
Default: 10485760 (10 mebibytes)
Valid Values: [4,…​]
Importance: medium
Dynamic update: cluster-wide

The maximum size in bytes of the offset index.

Type: string
Default: 3.0-IV1
Valid Values: [0.8.0, 0.8.1, 0.8.2, 0.9.0, 0.10.0-IV0, 0.10.0-IV1, 0.10.1-IV0, 0.10.1-IV1, 0.10.1-IV2, 0.10.2-IV0, 0.11.0-IV0, 0.11.0-IV1, 0.11.0-IV2, 1.0-IV0, 1.1-IV0, 2.0-IV0, 2.0-IV1, 2.1-IV0, 2.1-IV1, 2.1-IV2, 2.2-IV0, 2.2-IV1, 2.3-IV0, 2.3-IV1, 2.4-IV0, 2.4-IV1, 2.5-IV0, 2.6-IV0, 2.7-IV0, 2.7-IV1, 2.7-IV2, 2.8-IV0, 2.8-IV1, 3.0-IV0, 3.0-IV1, 3.1-IV0, 3.2-IV0]
Importance: medium
Dynamic update: read-only

Specify the message format version the broker will use to append messages to the logs. The value should be a valid ApiVersion. Some examples are: 0.8.2, 0.9.0.0, 0.10.0, check ApiVersion for more details. By setting a particular message format version, the user is certifying that all the existing messages on disk are smaller or equal than the specified version. Setting this value incorrectly will cause consumers with older versions to break as they will receive messages with a format that they don’t understand.

Type: long
Default: 9223372036854775807
Importance: medium
Dynamic update: cluster-wide

The maximum difference allowed between the timestamp when a broker receives a message and the timestamp specified in the message. If log.message.timestamp.type=CreateTime, a message will be rejected if the difference in timestamp exceeds this threshold. This configuration is ignored if log.message.timestamp.type=LogAppendTime.The maximum timestamp difference allowed should be no greater than log.retention.ms to avoid unnecessarily frequent log rolling.

Type: string
Default: CreateTime
Valid Values: [CreateTime, LogAppendTime]
Importance: medium
Dynamic update: cluster-wide

Define whether the timestamp in the message is message create time or log append time. The value should be either CreateTime or LogAppendTime.

Type: boolean
Default: false
Importance: medium
Dynamic update: cluster-wide

Should pre allocate file when create new segment? If you are using Kafka on Windows, you probably need to set it to true.

Type: long
Default: 300000 (5 minutes)
Valid Values: [1,…​]
Importance: medium
Dynamic update: read-only

The frequency in milliseconds that the log cleaner checks whether any log is eligible for deletion.

Type: int
Default: 2147483647
Valid Values: [0,…​]
Importance: medium
Dynamic update: cluster-wide

The maximum connection creation rate we allow in the broker at any time. Listener-level limits may also be configured by prefixing the config name with the listener prefix, for example, listener.name.internal.max.connection.creation.rate.Broker-wide connection rate limit should be configured based on broker capacity while listener limits should be configured based on application requirements. New connections will be throttled if either the listener or the broker limit is reached, with the exception of inter-broker listener. Connections on the inter-broker listener will be throttled only when the listener-level rate limit is reached.

Type: int
Default: 2147483647
Valid Values: [0,…​]
Importance: medium
Dynamic update: cluster-wide

The maximum number of connections we allow in the broker at any time. This limit is applied in addition to any per-ip limits configured using max.connections.per.ip. Listener-level limits may also be configured by prefixing the config name with the listener prefix, for example, listener.name.internal.max.connections. Broker-wide limit should be configured based on broker capacity while listener limits should be configured based on application requirements. New connections are blocked if either the listener or broker limit is reached. Connections on the inter-broker listener are permitted even if broker-wide limit is reached. The least recently used connection on another listener will be closed in this case.

Type: int
Default: 2147483647
Valid Values: [0,…​]
Importance: medium
Dynamic update: cluster-wide

The maximum number of connections we allow from each ip address. This can be set to 0 if there are overrides configured using max.connections.per.ip.overrides property. New connections from the ip address are dropped if the limit is reached.

Type: string
Default: ""
Importance: medium
Dynamic update: cluster-wide

A comma-separated list of per-ip or hostname overrides to the default maximum number of connections. An example value is "hostName:100,127.0.0.1:200".

Type: int
Default: 1000
Valid Values: [0,…​]
Importance: medium
Dynamic update: read-only

The maximum number of incremental fetch sessions that we will maintain.

Type: int
Default: 1
Valid Values: [1,…​]
Importance: medium
Dynamic update: read-only

The default number of log partitions per topic.

Type: password
Default: null
Importance: medium
Dynamic update: read-only

The old secret that was used for encoding dynamically configured passwords. This is required only when the secret is updated. If specified, all dynamically encoded passwords are decoded using this old secret and re-encoded using password.encoder.secret when broker starts up.

Type: password
Default: null
Importance: medium
Dynamic update: read-only

The secret used for encoding dynamically configured passwords for this broker.

Type: class
Default: org.apache.kafka.common.security.authenticator.DefaultKafkaPrincipalBuilder
Importance: medium
Dynamic update: per-broker

The fully qualified name of a class that implements the KafkaPrincipalBuilder interface, which is used to build the KafkaPrincipal object used during authorization. If no principal builder is defined, the default behavior depends on the security protocol in use. For SSL authentication, the principal will be derived using the rules defined by ssl.principal.mapping.rules applied on the distinguished name from the client certificate if one is provided; otherwise, if client authentication is not required, the principal name will be ANONYMOUS. For SASL authentication, the principal will be derived using the rules defined by sasl.kerberos.principal.to.local.rules if GSSAPI is in use, and the SASL authentication ID for other mechanisms. For PLAINTEXT, the principal will be ANONYMOUS.

Type: int
Default: 1000
Importance: medium
Dynamic update: read-only

The purge interval (in number of requests) of the producer request purgatory.

Type: long
Default: -1
Importance: medium
Dynamic update: read-only

The number of queued bytes allowed before no more requests are read.

Type: int
Default: 1000 (1 second)
Valid Values: [0,…​]
Importance: medium
Dynamic update: read-only

The amount of time to sleep when fetch partition error occurs.

Type: int
Default: 1048576 (1 mebibyte)
Valid Values: [0,…​]
Importance: medium
Dynamic update: read-only

The number of bytes of messages to attempt to fetch for each partition. This is not an absolute maximum, if the first record batch in the first non-empty partition of the fetch is larger than this value, the record batch will still be returned to ensure that progress can be made. The maximum record batch size accepted by the broker is defined via message.max.bytes (broker config) or max.message.bytes (topic config).

Type: int
Default: 10485760 (10 mebibytes)
Valid Values: [0,…​]
Importance: medium
Dynamic update: read-only

Maximum bytes expected for the entire fetch response. Records are fetched in batches, and if the first record batch in the first non-empty partition of the fetch is larger than this value, the record batch will still be returned to ensure that progress can be made. As such, this is not an absolute maximum. The maximum record batch size accepted by the broker is defined via message.max.bytes (broker config) or max.message.bytes (topic config).

Type: string
Default: null
Importance: medium
Dynamic update: read-only

The fully qualified class name that implements ReplicaSelector. This is used by the broker to find the preferred read replica. By default, we use an implementation that returns the leader.

Type: int
Default: 1000
Valid Values: [0,…​]
Importance: medium
Dynamic update: read-only

Max number that can be used for a broker.id.

Type: class
Default: null
Importance: medium
Dynamic update: read-only

The fully qualified name of a SASL client callback handler class that implements the AuthenticateCallbackHandler interface.

Type: list
Default: GSSAPI
Importance: medium
Dynamic update: per-broker

The list of SASL mechanisms enabled in the Kafka server. The list may contain any mechanism for which a security provider is available. Only GSSAPI is enabled by default.

Type: password
Default: null
Importance: medium
Dynamic update: per-broker

JAAS login context parameters for SASL connections in the format used by JAAS configuration files. JAAS configuration file format is described here. The format for the value is: loginModuleClass controlFlag (optionName=optionValue)*;. For brokers, the config must be prefixed with listener prefix and SASL mechanism name in lower-case. For example, listener.name.sasl_ssl.scram-sha-256.sasl.jaas.config=com.example.ScramLoginModule required;.

Type: string
Default: /usr/bin/kinit
Importance: medium
Dynamic update: per-broker

Kerberos kinit command path.

Type: long
Default: 60000
Importance: medium
Dynamic update: per-broker

Login thread sleep time between refresh attempts.

Type: list
Default: DEFAULT
Importance: medium
Dynamic update: per-broker

A list of rules for mapping from principal names to short names (typically operating system usernames). The rules are evaluated in order and the first rule that matches a principal name is used to map it to a short name. Any later rules in the list are ignored. By default, principal names of the form {username}/{hostname}@{REALM} are mapped to {username}. For more details on the format please see security authorization and acls. Note that this configuration is ignored if an extension of KafkaPrincipalBuilder is provided by the principal.builder.class configuration.

Type: string
Default: null
Importance: medium
Dynamic update: per-broker

The Kerberos principal name that Kafka runs as. This can be defined either in Kafka’s JAAS config or in Kafka’s config.

Type: double
Default: 0.05
Importance: medium
Dynamic update: per-broker

Percentage of random jitter added to the renewal time.

Type: double
Default: 0.8
Importance: medium
Dynamic update: per-broker

Login thread will sleep until the specified window factor of time from last refresh to ticket’s expiry has been reached, at which time it will try to renew the ticket.

Type: class
Default: null
Importance: medium
Dynamic update: read-only

The fully qualified name of a SASL login callback handler class that implements the AuthenticateCallbackHandler interface. For brokers, login callback handler config must be prefixed with listener prefix and SASL mechanism name in lower-case. For example, listener.name.sasl_ssl.scram-sha-256.sasl.login.callback.handler.class=com.example.CustomScramLoginCallbackHandler.

Type: class
Default: null
Importance: medium
Dynamic update: read-only

The fully qualified name of a class that implements the Login interface. For brokers, login config must be prefixed with listener prefix and SASL mechanism name in lower-case. For example, listener.name.sasl_ssl.scram-sha-256.sasl.login.class=com.example.CustomScramLogin.

Type: short
Default: 300
Importance: medium
Dynamic update: per-broker

The amount of buffer time before credential expiration to maintain when refreshing a credential, in seconds. If a refresh would otherwise occur closer to expiration than the number of buffer seconds then the refresh will be moved up to maintain as much of the buffer time as possible. Legal values are between 0 and 3600 (1 hour); a default value of 300 (5 minutes) is used if no value is specified. This value and sasl.login.refresh.min.period.seconds are both ignored if their sum exceeds the remaining lifetime of a credential. Currently applies only to OAUTHBEARER.

Type: short
Default: 60
Importance: medium
Dynamic update: per-broker

The desired minimum time for the login refresh thread to wait before refreshing a credential, in seconds. Legal values are between 0 and 900 (15 minutes); a default value of 60 (1 minute) is used if no value is specified. This value and sasl.login.refresh.buffer.seconds are both ignored if their sum exceeds the remaining lifetime of a credential. Currently applies only to OAUTHBEARER.

Type: double
Default: 0.8
Importance: medium
Dynamic update: per-broker

Login refresh thread will sleep until the specified window factor relative to the credential’s lifetime has been reached, at which time it will try to refresh the credential. Legal values are between 0.5 (50%) and 1.0 (100%) inclusive; a default value of 0.8 (80%) is used if no value is specified. Currently applies only to OAUTHBEARER.

Type: double
Default: 0.05
Importance: medium
Dynamic update: per-broker

The maximum amount of random jitter relative to the credential’s lifetime that is added to the login refresh thread’s sleep time. Legal values are between 0 and 0.25 (25%) inclusive; a default value of 0.05 (5%) is used if no value is specified. Currently applies only to OAUTHBEARER.

Type: string
Default: GSSAPI
Importance: medium
Dynamic update: per-broker

SASL mechanism used for inter-broker communication. Default is GSSAPI.

Type: string
Default: null
Importance: medium
Dynamic update: read-only

The OAuth/OIDC provider URL from which the provider’s JWKS (JSON Web Key Set) can be retrieved. The URL can be HTTP(S)-based or file-based. If the URL is HTTP(S)-based, the JWKS data will be retrieved from the OAuth/OIDC provider via the configured URL on broker startup. All then-current keys will be cached on the broker for incoming requests. If an authentication request is received for a JWT that includes a "kid" header claim value that isn’t yet in the cache, the JWKS endpoint will be queried again on demand. However, the broker polls the URL every sasl.oauthbearer.jwks.endpoint.refresh.ms milliseconds to refresh the cache with any forthcoming keys before any JWT requests that include them are received. If the URL is file-based, the broker will load the JWKS file from a configured location on startup. In the event that the JWT includes a "kid" header value that isn’t in the JWKS file, the broker will reject the JWT and authentication will fail.

Type: string
Default: null
Importance: medium
Dynamic update: read-only

The URL for the OAuth/OIDC identity provider. If the URL is HTTP(S)-based, it is the issuer’s token endpoint URL to which requests will be made to login based on the configuration in sasl.jaas.config. If the URL is file-based, it specifies a file containing an access token (in JWT serialized form) issued by the OAuth/OIDC identity provider to use for authorization.

Type: class
Default: null
Importance: medium
Dynamic update: read-only

The fully qualified name of a SASL server callback handler class that implements the AuthenticateCallbackHandler interface. Server callback handlers must be prefixed with listener prefix and SASL mechanism name in lower-case. For example, listener.name.sasl_ssl.plain.sasl.server.callback.handler.class=com.example.CustomPlainCallbackHandler.

Type: string
Default: PLAINTEXT
Importance: medium
Dynamic update: read-only

Security protocol used to communicate between brokers. Valid values are: PLAINTEXT, SSL, SASL_PLAINTEXT, SASL_SSL. It is an error to set this and inter.broker.listener.name properties at the same time.

Type: long
Default: 30000 (30 seconds)
Importance: medium
Dynamic update: read-only

The maximum amount of time the client will wait for the socket connection to be established. The connection setup timeout will increase exponentially for each consecutive connection failure up to this maximum. To avoid connection storms, a randomization factor of 0.2 will be applied to the timeout resulting in a random range between 20% below and 20% above the computed value.

Type: long
Default: 10000 (10 seconds)
Importance: medium
Dynamic update: read-only

The amount of time the client will wait for the socket connection to be established. If the connection is not built before the timeout elapses, clients will close the socket channel.

Type: int
Default: 50
Valid Values: [1,…​]
Importance: medium
Dynamic update: read-only

The maximum number of pending connections on the socket. In Linux, you may also need to configure somaxconn and tcp_max_syn_backlog kernel parameters accordingly to make the configuration takes effect.

Type: list
Default: ""
Importance: medium
Dynamic update: per-broker

A list of cipher suites. This is a named combination of authentication, encryption, MAC and key exchange algorithm used to negotiate the security settings for a network connection using TLS or SSL network protocol. By default all the available cipher suites are supported.

Type: string
Default: none
Valid Values: [required, requested, none]
Importance: medium
Dynamic update: per-broker

Configures kafka broker to request client authentication. The following settings are common:

Type: list
Default: TLSv1.2,TLSv1.3
Importance: medium
Dynamic update: per-broker

The list of protocols enabled for SSL connections. The default is 'TLSv1.2,TLSv1.3' when running with Java 11 or newer, 'TLSv1.2' otherwise. With the default value for Java 11, clients and servers will prefer TLSv1.3 if both support it and fallback to TLSv1.2 otherwise (assuming both support at least TLSv1.2). This default should be fine for most cases. Also see the config documentation for ssl.protocol.

Type: password
Default: null
Importance: medium
Dynamic update: per-broker

The password of the private key in the key store file or the PEM key specified in `ssl.keystore.key'. This is required for clients only if two-way authentication is configured.

Type: string
Default: SunX509
Importance: medium
Dynamic update: per-broker

The algorithm used by key manager factory for SSL connections. Default value is the key manager factory algorithm configured for the Java Virtual Machine.

Type: password
Default: null
Importance: medium
Dynamic update: per-broker

Certificate chain in the format specified by 'ssl.keystore.type'. Default SSL engine factory supports only PEM format with a list of X.509 certificates.

Type: password
Default: null
Importance: medium
Dynamic update: per-broker

Private key in the format specified by 'ssl.keystore.type'. Default SSL engine factory supports only PEM format with PKCS#8 keys. If the key is encrypted, key password must be specified using 'ssl.key.password'.

Type: string
Default: null
Importance: medium
Dynamic update: per-broker

The location of the key store file. This is optional for client and can be used for two-way authentication for client.

Type: password
Default: null
Importance: medium
Dynamic update: per-broker

The store password for the key store file. This is optional for client and only needed if 'ssl.keystore.location' is configured. Key store password is not supported for PEM format.

Type: string
Default: JKS
Importance: medium
Dynamic update: per-broker

The file format of the key store file. This is optional for client.

Type: string
Default: TLSv1.3
Importance: medium
Dynamic update: per-broker

The SSL protocol used to generate the SSLContext. The default is 'TLSv1.3' when running with Java 11 or newer, 'TLSv1.2' otherwise. This value should be fine for most use cases. Allowed values in recent JVMs are 'TLSv1.2' and 'TLSv1.3'. 'TLS', 'TLSv1.1', 'SSL', 'SSLv2' and 'SSLv3' may be supported in older JVMs, but their usage is discouraged due to known security vulnerabilities. With the default value for this config and 'ssl.enabled.protocols', clients will downgrade to 'TLSv1.2' if the server does not support 'TLSv1.3'. If this config is set to 'TLSv1.2', clients will not use 'TLSv1.3' even if it is one of the values in ssl.enabled.protocols and the server only supports 'TLSv1.3'.

Type: string
Default: null
Importance: medium
Dynamic update: per-broker

The name of the security provider used for SSL connections. Default value is the default security provider of the JVM.

Type: string
Default: PKIX
Importance: medium
Dynamic update: per-broker

The algorithm used by trust manager factory for SSL connections. Default value is the trust manager factory algorithm configured for the Java Virtual Machine.

Type: password
Default: null
Importance: medium
Dynamic update: per-broker

Trusted certificates in the format specified by 'ssl.truststore.type'. Default SSL engine factory supports only PEM format with X.509 certificates.

Type: string
Default: null
Importance: medium
Dynamic update: per-broker

The location of the trust store file.

Type: password
Default: null
Importance: medium
Dynamic update: per-broker

The password for the trust store file. If a password is not set, trust store file configured will still be used, but integrity checking is disabled. Trust store password is not supported for PEM format.

Type: string
Default: JKS
Importance: medium
Dynamic update: per-broker

The file format of the trust store file.

Type: string
Default: null
Importance: medium
Dynamic update: read-only

Typically set to org.apache.zookeeper.ClientCnxnSocketNetty when using TLS connectivity to ZooKeeper. Overrides any explicit value set via the same-named zookeeper.clientCnxnSocket system property.

Type: boolean
Default: false
Importance: medium
Dynamic update: read-only

Set client to use TLS when connecting to ZooKeeper. An explicit value overrides any value set via the zookeeper.client.secure system property (note the different name). Defaults to false if neither is set; when true, zookeeper.clientCnxnSocket must be set (typically to org.apache.zookeeper.ClientCnxnSocketNetty); other values to set may include zookeeper.ssl.cipher.suites, zookeeper.ssl.crl.enable, zookeeper.ssl.enabled.protocols, zookeeper.ssl.endpoint.identification.algorithm, zookeeper.ssl.keystore.location, zookeeper.ssl.keystore.password, zookeeper.ssl.keystore.type, zookeeper.ssl.ocsp.enable, zookeeper.ssl.protocol, zookeeper.ssl.truststore.location, zookeeper.ssl.truststore.password, zookeeper.ssl.truststore.type.

Type: string
Default: null
Importance: medium
Dynamic update: read-only

Keystore location when using a client-side certificate with TLS connectivity to ZooKeeper. Overrides any explicit value set via the zookeeper.ssl.keyStore.location system property (note the camelCase).

Type: password
Default: null
Importance: medium
Dynamic update: read-only

Keystore password when using a client-side certificate with TLS connectivity to ZooKeeper. Overrides any explicit value set via the zookeeper.ssl.keyStore.password system property (note the camelCase). Note that ZooKeeper does not support a key password different from the keystore password, so be sure to set the key password in the keystore to be identical to the keystore password; otherwise the connection attempt to Zookeeper will fail.

Type: string
Default: null
Importance: medium
Dynamic update: read-only

Keystore type when using a client-side certificate with TLS connectivity to ZooKeeper. Overrides any explicit value set via the zookeeper.ssl.keyStore.type system property (note the camelCase). The default value of null means the type will be auto-detected based on the filename extension of the keystore.

Type: string
Default: null
Importance: medium
Dynamic update: read-only

Truststore location when using TLS connectivity to ZooKeeper. Overrides any explicit value set via the zookeeper.ssl.trustStore.location system property (note the camelCase).

Type: password
Default: null
Importance: medium
Dynamic update: read-only

Truststore password when using TLS connectivity to ZooKeeper. Overrides any explicit value set via the zookeeper.ssl.trustStore.password system property (note the camelCase).

Type: string
Default: null
Importance: medium
Dynamic update: read-only

Truststore type when using TLS connectivity to ZooKeeper. Overrides any explicit value set via the zookeeper.ssl.trustStore.type system property (note the camelCase). The default value of null means the type will be auto-detected based on the filename extension of the truststore.

Type: class
Default: null
Importance: low
Dynamic update: read-only

The alter configs policy class that should be used for validation. The class should implement the org.apache.kafka.server.policy.AlterConfigPolicy interface.

Type: int
Default: 11
Valid Values: [1,…​]
Importance: low
Dynamic update: read-only

The number of samples to retain in memory for alter log dirs replication quotas.

Type: int
Default: 1
Valid Values: [1,…​]
Importance: low
Dynamic update: read-only

The time span of each sample for alter log dirs replication quotas.

Type: string
Default: ""
Importance: low
Dynamic update: read-only

The fully qualified name of a class that implements org.apache.kafka.server.authorizer.Authorizer interface, which is used by the broker for authorization.

Type: class
Default: null
Importance: low
Dynamic update: read-only

The fully qualified name of a class that implements the ClientQuotaCallback interface, which is used to determine quota limits applied to client requests. By default, <user>, <client-id>, <user> or <client-id> quotas stored in ZooKeeper are applied. For any given request, the most specific quota that matches the user principal of the session and the client-id of the request is applied.

Type: int
Default: 100
Valid Values: [0,…​]
Importance: low
Dynamic update: read-only

Connection close delay on failed authentication: this is the time (in milliseconds) by which connection close will be delayed on authentication failure. This must be configured to be less than connections.max.idle.ms to prevent connection timeout.

Type: int
Default: 20
Importance: low
Dynamic update: read-only

The amount of time to wait before attempting to retry a failed request to a given topic partition. This avoids repeatedly sending requests in a tight loop under some failure scenarios.

Type: int
Default: 11
Valid Values: [1,…​]
Importance: low
Dynamic update: read-only

The number of samples to retain in memory for controller mutation quotas.

Type: int
Default: 1
Valid Values: [1,…​]
Importance: low
Dynamic update: read-only

The time span of each sample for controller mutations quotas.

Type: class
Default: null
Importance: low
Dynamic update: read-only

The create topic policy class that should be used for validation. The class should implement the org.apache.kafka.server.policy.CreateTopicPolicy interface.

Type: long
Default: 3600000 (1 hour)
Valid Values: [1,…​]
Importance: low
Dynamic update: read-only

Scan interval to remove expired delegation tokens.

Type: int
Default: 10
Valid Values: [1,…​]
Importance: low
Dynamic update: read-only

The metrics polling interval (in seconds) which can be used in kafka.metrics.reporters implementations.

Type: list
Default: ""
Importance: low
Dynamic update: read-only

A list of classes to use as Yammer metrics custom reporters. The reporters should implement kafka.metrics.KafkaMetricsReporter trait. If a client wants to expose JMX operations on a custom reporter, the custom reporter needs to additionally implement an MBean trait that extends kafka.metrics.KafkaMetricsReporterMBean trait so that the registered MBean is compliant with the standard MBean convention.

Type: string
Default: PLAINTEXT:PLAINTEXT,SSL:SSL,SASL_PLAINTEXT:SASL_PLAINTEXT,SASL_SSL:SASL_SSL
Importance: low
Dynamic update: per-broker

Map between listener names and security protocols. This must be defined for the same security protocol to be usable in more than one port or IP. For example, internal and external traffic can be separated even if SSL is required for both. Concretely, the user could define listeners with names INTERNAL and EXTERNAL and this property as: INTERNAL:SSL,EXTERNAL:SSL. As shown, key and value are separated by a colon and map entries are separated by commas. Each listener name should only appear once in the map. Different security (SSL and SASL) settings can be configured for each listener by adding a normalised prefix (the listener name is lowercased) to the config name. For example, to set a different keystore for the INTERNAL listener, a config with name listener.name.internal.ssl.keystore.location would be set. If the config for the listener name is not set, the config will fallback to the generic config (i.e. ssl.keystore.location). Note that in KRaft a default mapping from the listener names defined by controller.listener.names to PLAINTEXT is assumed if no explicit mapping is provided and no other security protocol is in use.

Type: boolean
Default: true
Importance: low
Dynamic update: cluster-wide

This configuration controls whether down-conversion of message formats is enabled to satisfy consume requests. When set to false, broker will not perform down-conversion for consumers expecting an older message format. The broker responds with UNSUPPORTED_VERSION error for consume requests from such older clients. This configurationdoes not apply to any message format conversion that might be required for replication to followers.

Type: list
Default: ""
Importance: low
Dynamic update: cluster-wide

A list of classes to use as metrics reporters. Implementing the org.apache.kafka.common.metrics.MetricsReporter interface allows plugging in classes that will be notified of new metric creation. The JmxReporter is always included to register JMX statistics.

Type: int
Default: 2
Valid Values: [1,…​]
Importance: low
Dynamic update: read-only

The number of samples maintained to compute metrics.

Type: string
Default: INFO
Importance: low
Dynamic update: read-only

The highest recording level for metrics.

Type: long
Default: 30000 (30 seconds)
Valid Values: [1,…​]
Importance: low
Dynamic update: read-only

The window of time a metrics sample is computed over.

Type: string
Default: AES/CBC/PKCS5Padding
Importance: low
Dynamic update: read-only

The Cipher algorithm used for encoding dynamically configured passwords.

Type: int
Default: 4096
Valid Values: [1024,…​]
Importance: low
Dynamic update: read-only

The iteration count used for encoding dynamically configured passwords.

Type: int
Default: 128
Valid Values: [8,…​]
Importance: low
Dynamic update: read-only

The key length used for encoding dynamically configured passwords.

Type: string
Default: null
Importance: low
Dynamic update: read-only

The SecretKeyFactory algorithm used for encoding dynamically configured passwords. Default is PBKDF2WithHmacSHA512 if available and PBKDF2WithHmacSHA1 otherwise.

Type: int
Default: 11
Valid Values: [1,…​]
Importance: low
Dynamic update: read-only

The number of samples to retain in memory for client quotas.

Type: int
Default: 1
Valid Values: [1,…​]
Importance: low
Dynamic update: read-only

The time span of each sample for client quotas.

Type: int
Default: 11
Valid Values: [1,…​]
Importance: low
Dynamic update: read-only

The number of samples to retain in memory for replication quotas.

Type: int
Default: 1
Valid Values: [1,…​]
Importance: low
Dynamic update: read-only

The time span of each sample for replication quotas.

Type: int
Default: null
Importance: low
Dynamic update: read-only

The (optional) value in milliseconds for the external authentication provider connection timeout. Currently applies only to OAUTHBEARER.

Type: int
Default: null
Importance: low
Dynamic update: read-only

The (optional) value in milliseconds for the external authentication provider read timeout. Currently applies only to OAUTHBEARER.

Type: long
Default: 10000 (10 seconds)
Importance: low
Dynamic update: read-only

The (optional) value in milliseconds for the maximum wait between login attempts to the external authentication provider. Login uses an exponential backoff algorithm with an initial wait based on the sasl.login.retry.backoff.ms setting and will double in wait length between attempts up to a maximum wait length specified by the sasl.login.retry.backoff.max.ms setting. Currently applies only to OAUTHBEARER.

Type: long
Default: 100
Importance: low
Dynamic update: read-only

The (optional) value in milliseconds for the initial wait between login attempts to the external authentication provider. Login uses an exponential backoff algorithm with an initial wait based on the sasl.login.retry.backoff.ms setting and will double in wait length between attempts up to a maximum wait length specified by the sasl.login.retry.backoff.max.ms setting. Currently applies only to OAUTHBEARER.

Type: int
Default: 30
Importance: low
Dynamic update: read-only

The (optional) value in seconds to allow for differences between the time of the OAuth/OIDC identity provider and the broker.

Type: list
Default: null
Importance: low
Dynamic update: read-only

The (optional) comma-delimited setting for the broker to use to verify that the JWT was issued for one of the expected audiences. The JWT will be inspected for the standard OAuth "aud" claim and if this value is set, the broker will match the value from JWT’s "aud" claim to see if there is an exact match. If there is no match, the broker will reject the JWT and authentication will fail.

Type: string
Default: null
Importance: low
Dynamic update: read-only

The (optional) setting for the broker to use to verify that the JWT was created by the expected issuer. The JWT will be inspected for the standard OAuth "iss" claim and if this value is set, the broker will match it exactly against what is in the JWT’s "iss" claim. If there is no match, the broker will reject the JWT and authentication will fail.

Type: long
Default: 3600000 (1 hour)
Importance: low
Dynamic update: read-only

The (optional) value in milliseconds for the broker to wait between refreshing its JWKS (JSON Web Key Set) cache that contains the keys to verify the signature of the JWT.

Type: long
Default: 10000 (10 seconds)
Importance: low
Dynamic update: read-only

The (optional) value in milliseconds for the maximum wait between attempts to retrieve the JWKS (JSON Web Key Set) from the external authentication provider. JWKS retrieval uses an exponential backoff algorithm with an initial wait based on the sasl.oauthbearer.jwks.endpoint.retry.backoff.ms setting and will double in wait length between attempts up to a maximum wait length specified by the sasl.oauthbearer.jwks.endpoint.retry.backoff.max.ms setting.

Type: long
Default: 100
Importance: low
Dynamic update: read-only

The (optional) value in milliseconds for the initial wait between JWKS (JSON Web Key Set) retrieval attempts from the external authentication provider. JWKS retrieval uses an exponential backoff algorithm with an initial wait based on the sasl.oauthbearer.jwks.endpoint.retry.backoff.ms setting and will double in wait length between attempts up to a maximum wait length specified by the sasl.oauthbearer.jwks.endpoint.retry.backoff.max.ms setting.

Type: string
Default: scope
Importance: low
Dynamic update: read-only

The OAuth claim for the scope is often named "scope", but this (optional) setting can provide a different name to use for the scope included in the JWT payload’s claims if the OAuth/OIDC provider uses a different name for that claim.

Type: string
Default: sub
Importance: low
Dynamic update: read-only

The OAuth claim for the subject is often named "sub", but this (optional) setting can provide a different name to use for the subject included in the JWT payload’s claims if the OAuth/OIDC provider uses a different name for that claim.

Type: string
Default: null
Importance: low
Dynamic update: read-only

A list of configurable creator classes each returning a provider implementing security algorithms. These classes should implement the org.apache.kafka.common.security.auth.SecurityProviderCreator interface.

Type: string
Default: https
Importance: low
Dynamic update: per-broker

The endpoint identification algorithm to validate server hostname using server certificate.

Type: class
Default: null
Importance: low
Dynamic update: per-broker

The class of type org.apache.kafka.common.security.auth.SslEngineFactory to provide SSLEngine objects. Default value is org.apache.kafka.common.security.ssl.DefaultSslEngineFactory.

Type: string
Default: DEFAULT
Importance: low
Dynamic update: read-only

A list of rules for mapping from distinguished name from the client certificate to short name. The rules are evaluated in order and the first rule that matches a principal name is used to map it to a short name. Any later rules in the list are ignored. By default, distinguished name of the X.500 certificate will be the principal. For more details on the format please see security authorization and acls. Note that this configuration is ignored if an extension of KafkaPrincipalBuilder is provided by the principal.builder.class configuration.

Type: string
Default: null
Importance: low
Dynamic update: per-broker

The SecureRandom PRNG implementation to use for SSL cryptography operations.

Type: int
Default: 10000 (10 seconds)
Valid Values: [1,…​]
Importance: low
Dynamic update: read-only

The interval at which to rollback transactions that have timed out.

Type: int
Default: 3600000 (1 hour)
Valid Values: [1,…​]
Importance: low
Dynamic update: read-only

The interval at which to remove transactions that have expired due to transactional.id.expiration.ms passing.

Type: list
Default: null
Importance: low
Dynamic update: read-only

Specifies the enabled cipher suites to be used in ZooKeeper TLS negotiation (csv). Overrides any explicit value set via the zookeeper.ssl.ciphersuites system property (note the single word "ciphersuites"). The default value of null means the list of enabled cipher suites is determined by the Java runtime being used.

Type: boolean
Default: false
Importance: low
Dynamic update: read-only

Specifies whether to enable Certificate Revocation List in the ZooKeeper TLS protocols. Overrides any explicit value set via the zookeeper.ssl.crl system property (note the shorter name).

Type: list
Default: null
Importance: low
Dynamic update: read-only

Specifies the enabled protocol(s) in ZooKeeper TLS negotiation (csv). Overrides any explicit value set via the zookeeper.ssl.enabledProtocols system property (note the camelCase). The default value of null means the enabled protocol will be the value of the zookeeper.ssl.protocol configuration property.

Type: string
Default: HTTPS
Importance: low
Dynamic update: read-only

Specifies whether to enable hostname verification in the ZooKeeper TLS negotiation process, with (case-insensitively) "https" meaning ZooKeeper hostname verification is enabled and an explicit blank value meaning it is disabled (disabling it is only recommended for testing purposes). An explicit value overrides any "true" or "false" value set via the zookeeper.ssl.hostnameVerification system property (note the different name and values; true implies https and false implies blank).

Type: boolean
Default: false
Importance: low
Dynamic update: read-only

Specifies whether to enable Online Certificate Status Protocol in the ZooKeeper TLS protocols. Overrides any explicit value set via the zookeeper.ssl.ocsp system property (note the shorter name).

Type: string
Default: TLSv1.2
Importance: low
Dynamic update: read-only

Specifies the protocol to be used in ZooKeeper TLS negotiation. An explicit value overrides any value set via the same-named zookeeper.ssl.protocol system property.

Type: list
Default: delete
Valid Values: [compact, delete]
Server Default Property: log.cleanup.policy
Importance: medium

A string that is either "delete" or "compact" or both. This string designates the retention policy to use on old log segments. The default policy ("delete") will discard old segments when their retention time or size limit has been reached. The "compact" setting will enable log compaction on the topic.

Type: string
Default: producer
Valid Values: [uncompressed, zstd, lz4, snappy, gzip, producer]
Server Default Property: compression.type
Importance: medium

Specify the final compression type for a given topic. This configuration accepts the standard compression codecs ('gzip', 'snappy', 'lz4', 'zstd'). It additionally accepts 'uncompressed' which is equivalent to no compression; and 'producer' which means retain the original compression codec set by the producer.

Type: long
Default: 86400000 (1 day)
Valid Values: [0,…​]
Server Default Property: log.cleaner.delete.retention.ms
Importance: medium

The amount of time to retain delete tombstone markers for log compacted topics. This setting also gives a bound on the time in which a consumer must complete a read if they begin from offset 0 to ensure that they get a valid snapshot of the final stage (otherwise delete tombstones may be collected before they complete their scan).

Type: long
Default: 60000 (1 minute)
Valid Values: [0,…​]
Server Default Property: log.segment.delete.delay.ms
Importance: medium

The time to wait before deleting a file from the filesystem.

Type: long
Default: 9223372036854775807
Valid Values: [0,…​]
Server Default Property: log.flush.interval.messages
Importance: medium

This setting allows specifying an interval at which we will force an fsync of data written to the log. For example if this was set to 1 we would fsync after every message; if it were 5 we would fsync after every five messages. In general we recommend you not set this and use replication for durability and allow the operating system’s background flush capabilities as it is more efficient. This setting can be overridden on a per-topic basis (see the per-topic configuration section).

Type: long
Default: 9223372036854775807
Valid Values: [0,…​]
Server Default Property: log.flush.interval.ms
Importance: medium

This setting allows specifying a time interval at which we will force an fsync of data written to the log. For example if this was set to 1000 we would fsync after 1000 ms had passed. In general we recommend you not set this and use replication for durability and allow the operating system’s background flush capabilities as it is more efficient.

Type: list
Default: ""
Valid Values: [partitionId]:[brokerId],[partitionId]:[brokerId],…​
Server Default Property: follower.replication.throttled.replicas
Importance: medium

A list of replicas for which log replication should be throttled on the follower side. The list should describe a set of replicas in the form [PartitionId]:[BrokerId],[PartitionId]:[BrokerId]:…​ or alternatively the wildcard '*' can be used to throttle all replicas for this topic.

Type: int
Default: 4096 (4 kibibytes)
Valid Values: [0,…​]
Server Default Property: log.index.interval.bytes
Importance: medium

This setting controls how frequently Kafka adds an index entry to its offset index. The default setting ensures that we index a message roughly every 4096 bytes. More indexing allows reads to jump closer to the exact position in the log but makes the index larger. You probably don’t need to change this.

Type: list
Default: ""
Valid Values: [partitionId]:[brokerId],[partitionId]:[brokerId],…​
Server Default Property: leader.replication.throttled.replicas
Importance: medium

A list of replicas for which log replication should be throttled on the leader side. The list should describe a set of replicas in the form [PartitionId]:[BrokerId],[PartitionId]:[BrokerId]:…​ or alternatively the wildcard '*' can be used to throttle all replicas for this topic.

Type: long
Default: 9223372036854775807
Valid Values: [1,…​]
Server Default Property: log.cleaner.max.compaction.lag.ms
Importance: medium

The maximum time a message will remain ineligible for compaction in the log. Only applicable for logs that are being compacted.

Type: int
Default: 1048588
Valid Values: [0,…​]
Server Default Property: message.max.bytes
Importance: medium

The largest record batch size allowed by Kafka (after compression if compression is enabled). If this is increased and there are consumers older than 0.10.2, the consumers' fetch size must also be increased so that they can fetch record batches this large. In the latest message format version, records are always grouped into batches for efficiency. In previous message format versions, uncompressed records are not grouped into batches and this limit only applies to a single record in that case.

Type: string
Default: 3.0-IV1
Valid Values: [0.8.0, 0.8.1, 0.8.2, 0.9.0, 0.10.0-IV0, 0.10.0-IV1, 0.10.1-IV0, 0.10.1-IV1, 0.10.1-IV2, 0.10.2-IV0, 0.11.0-IV0, 0.11.0-IV1, 0.11.0-IV2, 1.0-IV0, 1.1-IV0, 2.0-IV0, 2.0-IV1, 2.1-IV0, 2.1-IV1, 2.1-IV2, 2.2-IV0, 2.2-IV1, 2.3-IV0, 2.3-IV1, 2.4-IV0, 2.4-IV1, 2.5-IV0, 2.6-IV0, 2.7-IV0, 2.7-IV1, 2.7-IV2, 2.8-IV0, 2.8-IV1, 3.0-IV0, 3.0-IV1, 3.1-IV0, 3.2-IV0]
Server Default Property: log.message.format.version
Importance: medium

[DEPRECATED] Specify the message format version the broker will use to append messages to the logs. The value of this config is always assumed to be 3.0 if inter.broker.protocol.version is 3.0 or higher (the actual config value is ignored). Otherwise, the value should be a valid ApiVersion. Some examples are: 0.10.0, 1.1, 2.8, 3.0. By setting a particular message format version, the user is certifying that all the existing messages on disk are smaller or equal than the specified version. Setting this value incorrectly will cause consumers with older versions to break as they will receive messages with a format that they don’t understand.

Type: long
Default: 9223372036854775807
Valid Values: [0,…​]
Server Default Property: log.message.timestamp.difference.max.ms
Importance: medium

The maximum difference allowed between the timestamp when a broker receives a message and the timestamp specified in the message. If message.timestamp.type=CreateTime, a message will be rejected if the difference in timestamp exceeds this threshold. This configuration is ignored if message.timestamp.type=LogAppendTime.

Type: string
Default: CreateTime
Valid Values: [CreateTime, LogAppendTime]
Server Default Property: log.message.timestamp.type
Importance: medium

Define whether the timestamp in the message is message create time or log append time. The value should be either CreateTime or LogAppendTime.

Type: double
Default: 0.5
Valid Values: [0,…​,1]
Server Default Property: log.cleaner.min.cleanable.ratio
Importance: medium

This configuration controls how frequently the log compactor will attempt to clean the log (assuming log compaction is enabled). By default we will avoid cleaning a log where more than 50% of the log has been compacted. This ratio bounds the maximum space wasted in the log by duplicates (at 50% at most 50% of the log could be duplicates). A higher ratio will mean fewer, more efficient cleanings but will mean more wasted space in the log. If the max.compaction.lag.ms or the min.compaction.lag.ms configurations are also specified, then the log compactor considers the log to be eligible for compaction as soon as either: (i) the dirty ratio threshold has been met and the log has had dirty (uncompacted) records for at least the min.compaction.lag.ms duration, or (ii) if the log has had dirty (uncompacted) records for at most the max.compaction.lag.ms period.

Type: long
Default: 0
Valid Values: [0,…​]
Server Default Property: log.cleaner.min.compaction.lag.ms
Importance: medium

The minimum time a message will remain uncompacted in the log. Only applicable for logs that are being compacted.

Type: int
Default: 1
Valid Values: [1,…​]
Server Default Property: min.insync.replicas
Importance: medium

When a producer sets acks to "all" (or "-1"), this configuration specifies the minimum number of replicas that must acknowledge a write for the write to be considered successful. If this minimum cannot be met, then the producer will raise an exception (either NotEnoughReplicas or NotEnoughReplicasAfterAppend). When used together, min.insync.replicas and acks allow you to enforce greater durability guarantees. A typical scenario would be to create a topic with a replication factor of 3, set min.insync.replicas to 2, and produce with acks of "all". This will ensure that the producer raises an exception if a majority of replicas do not receive a write.

Type: boolean
Default: false
Server Default Property: log.preallocate
Importance: medium

True if we should preallocate the file on disk when creating a new log segment.

Type: long
Default: -1
Server Default Property: log.retention.bytes
Importance: medium

This configuration controls the maximum size a partition (which consists of log segments) can grow to before we will discard old log segments to free up space if we are using the "delete" retention policy. By default there is no size limit only a time limit. Since this limit is enforced at the partition level, multiply it by the number of partitions to compute the topic retention in bytes.

Type: long
Default: 604800000 (7 days)
Valid Values: [-1,…​]
Server Default Property: log.retention.ms
Importance: medium

This configuration controls the maximum time we will retain a log before we will discard old log segments to free up space if we are using the "delete" retention policy. This represents an SLA on how soon consumers must read their data. If set to -1, no time limit is applied.

Type: int
Default: 1073741824 (1 gibibyte)
Valid Values: [14,…​]
Server Default Property: log.segment.bytes
Importance: medium

This configuration controls the segment file size for the log. Retention and cleaning is always done a file at a time so a larger segment size means fewer files but less granular control over retention.

Type: int
Default: 10485760 (10 mebibytes)
Valid Values: [0,…​]
Server Default Property: log.index.size.max.bytes
Importance: medium

This configuration controls the size of the index that maps offsets to file positions. We preallocate this index file and shrink it only after log rolls. You generally should not need to change this setting.

Type: long
Default: 0
Valid Values: [0,…​]
Server Default Property: log.roll.jitter.ms
Importance: medium

The maximum random jitter subtracted from the scheduled segment roll time to avoid thundering herds of segment rolling.

Type: long
Default: 604800000 (7 days)
Valid Values: [1,…​]
Server Default Property: log.roll.ms
Importance: medium

This configuration controls the period of time after which Kafka will force the log to roll even if the segment file isn’t full to ensure that retention can delete or compact old data.

Type: boolean
Default: false
Server Default Property: unclean.leader.election.enable
Importance: medium

Indicates whether to enable replicas not in the ISR set to be elected as leader as a last resort, even though doing so may result in data loss.

Type: boolean
Default: true
Server Default Property: log.message.downconversion.enable
Importance: low

This configuration controls whether down-conversion of message formats is enabled to satisfy consume requests. When set to false, broker will not perform down-conversion for consumers expecting an older message format. The broker responds with UNSUPPORTED_VERSION error for consume requests from such older clients. This configurationdoes not apply to any message format conversion that might be required for replication to followers.

Type: class
Importance: high

Deserializer class for key that implements the org.apache.kafka.common.serialization.Deserializer interface.

Type: class
Importance: high

Deserializer class for value that implements the org.apache.kafka.common.serialization.Deserializer interface.

Type: list
Default: ""
Valid Values: non-null string
Importance: high

A list of host/port pairs to use for establishing the initial connection to the Kafka cluster. The client will make use of all servers irrespective of which servers are specified here for bootstrapping—this list only impacts the initial hosts used to discover the full set of servers. This list should be in the form host1:port1,host2:port2,…​. Since these servers are just used for the initial connection to discover the full cluster membership (which may change dynamically), this list need not contain the full set of servers (you may want more than one, though, in case a server is down).

Type: int
Default: 1
Valid Values: [0,…​]
Importance: high

The minimum amount of data the server should return for a fetch request. If insufficient data is available the request will wait for that much data to accumulate before answering the request. The default setting of 1 byte means that fetch requests are answered as soon as a single byte of data is available or the fetch request times out waiting for data to arrive. Setting this to something greater than 1 will cause the server to wait for larger amounts of data to accumulate which can improve server throughput a bit at the cost of some additional latency.

Type: string
Default: null
Importance: high

A unique string that identifies the consumer group this consumer belongs to. This property is required if the consumer uses either the group management functionality by using subscribe(topic) or the Kafka-based offset management strategy.

Type: int
Default: 3000 (3 seconds)
Importance: high

The expected time between heartbeats to the consumer coordinator when using Kafka’s group management facilities. Heartbeats are used to ensure that the consumer’s session stays active and to facilitate rebalancing when new consumers join or leave the group. The value must be set lower than session.timeout.ms, but typically should be set no higher than 1/3 of that value. It can be adjusted even lower to control the expected time for normal rebalances.

Type: int
Default: 1048576 (1 mebibyte)
Valid Values: [0,…​]
Importance: high

The maximum amount of data per-partition the server will return. Records are fetched in batches by the consumer. If the first record batch in the first non-empty partition of the fetch is larger than this limit, the batch will still be returned to ensure that the consumer can make progress. The maximum record batch size accepted by the broker is defined via message.max.bytes (broker config) or max.message.bytes (topic config). See fetch.max.bytes for limiting the consumer request size.

Type: int
Default: 45000 (45 seconds)
Importance: high

The timeout used to detect client failures when using Kafka’s group management facility. The client sends periodic heartbeats to indicate its liveness to the broker. If no heartbeats are received by the broker before the expiration of this session timeout, then the broker will remove this client from the group and initiate a rebalance. Note that the value must be in the allowable range as configured in the broker configuration by group.min.session.timeout.ms and group.max.session.timeout.ms.

Type: password
Default: null
Importance: high

The password of the private key in the key store file or the PEM key specified in `ssl.keystore.key'. This is required for clients only if two-way authentication is configured.

Type: password
Default: null
Importance: high

Certificate chain in the format specified by 'ssl.keystore.type'. Default SSL engine factory supports only PEM format with a list of X.509 certificates.

Type: password
Default: null
Importance: high

Private key in the format specified by 'ssl.keystore.type'. Default SSL engine factory supports only PEM format with PKCS#8 keys. If the key is encrypted, key password must be specified using 'ssl.key.password'.

Type: string
Default: null
Importance: high

The location of the key store file. This is optional for client and can be used for two-way authentication for client.

Type: password
Default: null
Importance: high

The store password for the key store file. This is optional for client and only needed if 'ssl.keystore.location' is configured. Key store password is not supported for PEM format.

Type: password
Default: null
Importance: high

Trusted certificates in the format specified by 'ssl.truststore.type'. Default SSL engine factory supports only PEM format with X.509 certificates.

Type: string
Default: null
Importance: high

The location of the trust store file.

Type: password
Default: null
Importance: high

The password for the trust store file. If a password is not set, trust store file configured will still be used, but integrity checking is disabled. Trust store password is not supported for PEM format.

Type: boolean
Default: true
Importance: medium

Allow automatic topic creation on the broker when subscribing to or assigning a topic. A topic being subscribed to will be automatically created only if the broker allows for it using auto.create.topics.enable broker configuration. This configuration must be set to false when using brokers older than 0.11.0.

Type: string
Default: latest
Valid Values: [latest, earliest, none]
Importance: medium

What to do when there is no initial offset in Kafka or if the current offset does not exist any more on the server (e.g. because that data has been deleted):

Type: string
Default: use_all_dns_ips
Valid Values: [use_all_dns_ips, resolve_canonical_bootstrap_servers_only]
Importance: medium

Controls how the client uses DNS lookups. If set to use_all_dns_ips, connect to each returned IP address in sequence until a successful connection is established. After a disconnection, the next IP is used. Once all IPs have been used once, the client resolves the IP(s) from the hostname again (both the JVM and the OS cache DNS name lookups, however). If set to resolve_canonical_bootstrap_servers_only, resolve each bootstrap address into a list of canonical names. After the bootstrap phase, this behaves the same as use_all_dns_ips.

Type: long
Default: 540000 (9 minutes)
Importance: medium

Close idle connections after the number of milliseconds specified by this config.

Type: int
Default: 60000 (1 minute)
Valid Values: [0,…​]
Importance: medium

Specifies the timeout (in milliseconds) for client APIs. This configuration is used as the default timeout for all client operations that do not specify a timeout parameter.

Type: boolean
Default: true
Importance: medium

If true the consumer’s offset will be periodically committed in the background.

Type: boolean
Default: true
Importance: medium

Whether internal topics matching a subscribed pattern should be excluded from the subscription. It is always possible to explicitly subscribe to an internal topic.

Type: int
Default: 52428800 (50 mebibytes)
Valid Values: [0,…​]
Importance: medium

The maximum amount of data the server should return for a fetch request. Records are fetched in batches by the consumer, and if the first record batch in the first non-empty partition of the fetch is larger than this value, the record batch will still be returned to ensure that the consumer can make progress. As such, this is not a absolute maximum. The maximum record batch size accepted by the broker is defined via message.max.bytes (broker config) or max.message.bytes (topic config). Note that the consumer performs multiple fetches in parallel.

Type: string
Default: null
Importance: medium

A unique identifier of the consumer instance provided by the end user. Only non-empty strings are permitted. If set, the consumer is treated as a static member, which means that only one instance with this ID is allowed in the consumer group at any time. This can be used in combination with a larger session timeout to avoid group rebalances caused by transient unavailability (e.g. process restarts). If not set, the consumer will join the group as a dynamic member, which is the traditional behavior.

Type: string
Default: read_uncommitted
Valid Values: [read_committed, read_uncommitted]
Importance: medium

Controls how to read messages written transactionally. If set to read_committed, consumer.poll() will only return transactional messages which have been committed. If set to read_uncommitted (the default), consumer.poll() will return all messages, even transactional messages which have been aborted. Non-transactional messages will be returned unconditionally in either mode.

Messages will always be returned in offset order. Hence, in read_committed mode, consumer.poll() will only return messages up to the last stable offset (LSO), which is the one less than the offset of the first open transaction. In particular any messages appearing after messages belonging to ongoing transactions will be withheld until the relevant transaction has been completed. As a result, read_committed consumers will not be able to read up to the high watermark when there are in flight transactions.

 Further, when in `read_committed` the seekToEnd method will return the LSO
.

Type: int
Default: 300000 (5 minutes)
Valid Values: [1,…​]
Importance: medium

The maximum delay between invocations of poll() when using consumer group management. This places an upper bound on the amount of time that the consumer can be idle before fetching more records. If poll() is not called before expiration of this timeout, then the consumer is considered failed and the group will rebalance in order to reassign the partitions to another member. For consumers using a non-null group.instance.id which reach this timeout, partitions will not be immediately reassigned. Instead, the consumer will stop sending heartbeats and partitions will be reassigned after expiration of session.timeout.ms. This mirrors the behavior of a static consumer which has shutdown.

Type: int
Default: 500
Valid Values: [1,…​]
Importance: medium

The maximum number of records returned in a single call to poll(). Note, that max.poll.records does not impact the underlying fetching behavior. The consumer will cache the records from each fetch request and returns them incrementally from each poll.

Type: list
Default: class org.apache.kafka.clients.consumer.RangeAssignor,class org.apache.kafka.clients.consumer.CooperativeStickyAssignor
Valid Values: non-null string
Importance: medium

A list of class names or class types, ordered by preference, of supported partition assignment strategies that the client will use to distribute partition ownership amongst consumer instances when group management is used. Available options are:

Type: int
Default: 65536 (64 kibibytes)
Valid Values: [-1,…​]
Importance: medium

The size of the TCP receive buffer (SO_RCVBUF) to use when reading data. If the value is -1, the OS default will be used.

Type: int
Default: 30000 (30 seconds)
Valid Values: [0,…​]
Importance: medium

The configuration controls the maximum amount of time the client will wait for the response of a request. If the response is not received before the timeout elapses the client will resend the request if necessary or fail the request if retries are exhausted.

Type: class
Default: null
Importance: medium

The fully qualified name of a SASL client callback handler class that implements the AuthenticateCallbackHandler interface.

Type: password
Default: null
Importance: medium

JAAS login context parameters for SASL connections in the format used by JAAS configuration files. JAAS configuration file format is described here. The format for the value is: loginModuleClass controlFlag (optionName=optionValue)*;. For brokers, the config must be prefixed with listener prefix and SASL mechanism name in lower-case. For example, listener.name.sasl_ssl.scram-sha-256.sasl.jaas.config=com.example.ScramLoginModule required;.

Type: string
Default: null
Importance: medium

The Kerberos principal name that Kafka runs as. This can be defined either in Kafka’s JAAS config or in Kafka’s config.

Type: class
Default: null
Importance: medium

The fully qualified name of a SASL login callback handler class that implements the AuthenticateCallbackHandler interface. For brokers, login callback handler config must be prefixed with listener prefix and SASL mechanism name in lower-case. For example, listener.name.sasl_ssl.scram-sha-256.sasl.login.callback.handler.class=com.example.CustomScramLoginCallbackHandler.

Type: class
Default: null
Importance: medium

The fully qualified name of a class that implements the Login interface. For brokers, login config must be prefixed with listener prefix and SASL mechanism name in lower-case. For example, listener.name.sasl_ssl.scram-sha-256.sasl.login.class=com.example.CustomScramLogin.

Type: string
Default: GSSAPI
Importance: medium

SASL mechanism used for client connections. This may be any mechanism for which a security provider is available. GSSAPI is the default mechanism.

Type: string
Default: null
Importance: medium

The OAuth/OIDC provider URL from which the provider’s JWKS (JSON Web Key Set) can be retrieved. The URL can be HTTP(S)-based or file-based. If the URL is HTTP(S)-based, the JWKS data will be retrieved from the OAuth/OIDC provider via the configured URL on broker startup. All then-current keys will be cached on the broker for incoming requests. If an authentication request is received for a JWT that includes a "kid" header claim value that isn’t yet in the cache, the JWKS endpoint will be queried again on demand. However, the broker polls the URL every sasl.oauthbearer.jwks.endpoint.refresh.ms milliseconds to refresh the cache with any forthcoming keys before any JWT requests that include them are received. If the URL is file-based, the broker will load the JWKS file from a configured location on startup. In the event that the JWT includes a "kid" header value that isn’t in the JWKS file, the broker will reject the JWT and authentication will fail.

Type: string
Default: null
Importance: medium

The URL for the OAuth/OIDC identity provider. If the URL is HTTP(S)-based, it is the issuer’s token endpoint URL to which requests will be made to login based on the configuration in sasl.jaas.config. If the URL is file-based, it specifies a file containing an access token (in JWT serialized form) issued by the OAuth/OIDC identity provider to use for authorization.

Type: string
Default: PLAINTEXT
Importance: medium

Protocol used to communicate with brokers. Valid values are: PLAINTEXT, SSL, SASL_PLAINTEXT, SASL_SSL.

Type: int
Default: 131072 (128 kibibytes)
Valid Values: [-1,…​]
Importance: medium

The size of the TCP send buffer (SO_SNDBUF) to use when sending data. If the value is -1, the OS default will be used.

Type: long
Default: 30000 (30 seconds)
Importance: medium

The maximum amount of time the client will wait for the socket connection to be established. The connection setup timeout will increase exponentially for each consecutive connection failure up to this maximum. To avoid connection storms, a randomization factor of 0.2 will be applied to the timeout resulting in a random range between 20% below and 20% above the computed value.

Type: long
Default: 10000 (10 seconds)
Importance: medium

The amount of time the client will wait for the socket connection to be established. If the connection is not built before the timeout elapses, clients will close the socket channel.

Type: list
Default: TLSv1.2,TLSv1.3
Importance: medium

The list of protocols enabled for SSL connections. The default is 'TLSv1.2,TLSv1.3' when running with Java 11 or newer, 'TLSv1.2' otherwise. With the default value for Java 11, clients and servers will prefer TLSv1.3 if both support it and fallback to TLSv1.2 otherwise (assuming both support at least TLSv1.2). This default should be fine for most cases. Also see the config documentation for ssl.protocol.

Type: string
Default: JKS
Importance: medium

The file format of the key store file. This is optional for client.

Type: string
Default: TLSv1.3
Importance: medium

The SSL protocol used to generate the SSLContext. The default is 'TLSv1.3' when running with Java 11 or newer, 'TLSv1.2' otherwise. This value should be fine for most use cases. Allowed values in recent JVMs are 'TLSv1.2' and 'TLSv1.3'. 'TLS', 'TLSv1.1', 'SSL', 'SSLv2' and 'SSLv3' may be supported in older JVMs, but their usage is discouraged due to known security vulnerabilities. With the default value for this config and 'ssl.enabled.protocols', clients will downgrade to 'TLSv1.2' if the server does not support 'TLSv1.3'. If this config is set to 'TLSv1.2', clients will not use 'TLSv1.3' even if it is one of the values in ssl.enabled.protocols and the server only supports 'TLSv1.3'.

Type: string
Default: null
Importance: medium

The name of the security provider used for SSL connections. Default value is the default security provider of the JVM.

Type: string
Default: JKS
Importance: medium

The file format of the trust store file.

Type: int
Default: 5000 (5 seconds)
Valid Values: [0,…​]
Importance: low

The frequency in milliseconds that the consumer offsets are auto-committed to Kafka if enable.auto.commit is set to true.

Type: boolean
Default: true
Importance: low

Automatically check the CRC32 of the records consumed. This ensures no on-the-wire or on-disk corruption to the messages occurred. This check adds some overhead, so it may be disabled in cases seeking extreme performance.

Type: string
Default: ""
Importance: low

An id string to pass to the server when making requests. The purpose of this is to be able to track the source of requests beyond just ip/port by allowing a logical application name to be included in server-side request logging.

Type: string
Default: ""
Importance: low

A rack identifier for this client. This can be any string value which indicates where this client is physically located. It corresponds with the broker config 'broker.rack'.

Type: int
Default: 500
Valid Values: [0,…​]
Importance: low

The maximum amount of time the server will block before answering the fetch request if there isn’t sufficient data to immediately satisfy the requirement given by fetch.min.bytes.

Type: list
Default: ""
Valid Values: non-null string
Importance: low

A list of classes to use as interceptors. Implementing the org.apache.kafka.clients.consumer.ConsumerInterceptor interface allows you to intercept (and possibly mutate) records received by the consumer. By default, there are no interceptors.

Type: long
Default: 300000 (5 minutes)
Valid Values: [0,…​]
Importance: low

The period of time in milliseconds after which we force a refresh of metadata even if we haven’t seen any partition leadership changes to proactively discover any new brokers or partitions.

Type: list
Default: ""
Valid Values: non-null string
Importance: low

A list of classes to use as metrics reporters. Implementing the org.apache.kafka.common.metrics.MetricsReporter interface allows plugging in classes that will be notified of new metric creation. The JmxReporter is always included to register JMX statistics.

Type: int
Default: 2
Valid Values: [1,…​]
Importance: low

The number of samples maintained to compute metrics.

Type: string
Default: INFO
Valid Values: [INFO, DEBUG, TRACE]
Importance: low

The highest recording level for metrics.

Type: long
Default: 30000 (30 seconds)
Valid Values: [0,…​]
Importance: low

The window of time a metrics sample is computed over.

Type: long
Default: 1000 (1 second)
Valid Values: [0,…​]
Importance: low

The maximum amount of time in milliseconds to wait when reconnecting to a broker that has repeatedly failed to connect. If provided, the backoff per host will increase exponentially for each consecutive connection failure, up to this maximum. After calculating the backoff increase, 20% random jitter is added to avoid connection storms.

Type: long
Default: 50
Valid Values: [0,…​]
Importance: low

The base amount of time to wait before attempting to reconnect to a given host. This avoids repeatedly connecting to a host in a tight loop. This backoff applies to all connection attempts by the client to a broker.

Type: long
Default: 100
Valid Values: [0,…​]
Importance: low

The amount of time to wait before attempting to retry a failed request to a given topic partition. This avoids repeatedly sending requests in a tight loop under some failure scenarios.

Type: string
Default: /usr/bin/kinit
Importance: low

Kerberos kinit command path.

Type: long
Default: 60000
Importance: low

Login thread sleep time between refresh attempts.

Type: double
Default: 0.05
Importance: low

Percentage of random jitter added to the renewal time.

Type: double
Default: 0.8
Importance: low

Login thread will sleep until the specified window factor of time from last refresh to ticket’s expiry has been reached, at which time it will try to renew the ticket.

Type: int
Default: null
Importance: low

The (optional) value in milliseconds for the external authentication provider connection timeout. Currently applies only to OAUTHBEARER.

Type: int
Default: null
Importance: low

The (optional) value in milliseconds for the external authentication provider read timeout. Currently applies only to OAUTHBEARER.

Type: short
Default: 300
Valid Values: [0,…​,3600]
Importance: low

The amount of buffer time before credential expiration to maintain when refreshing a credential, in seconds. If a refresh would otherwise occur closer to expiration than the number of buffer seconds then the refresh will be moved up to maintain as much of the buffer time as possible. Legal values are between 0 and 3600 (1 hour); a default value of 300 (5 minutes) is used if no value is specified. This value and sasl.login.refresh.min.period.seconds are both ignored if their sum exceeds the remaining lifetime of a credential. Currently applies only to OAUTHBEARER.

Type: short
Default: 60
Valid Values: [0,…​,900]
Importance: low

The desired minimum time for the login refresh thread to wait before refreshing a credential, in seconds. Legal values are between 0 and 900 (15 minutes); a default value of 60 (1 minute) is used if no value is specified. This value and sasl.login.refresh.buffer.seconds are both ignored if their sum exceeds the remaining lifetime of a credential. Currently applies only to OAUTHBEARER.

Type: double
Default: 0.8
Valid Values: [0.5,…​,1.0]
Importance: low

Login refresh thread will sleep until the specified window factor relative to the credential’s lifetime has been reached, at which time it will try to refresh the credential. Legal values are between 0.5 (50%) and 1.0 (100%) inclusive; a default value of 0.8 (80%) is used if no value is specified. Currently applies only to OAUTHBEARER.

Type: double
Default: 0.05
Valid Values: [0.0,…​,0.25]
Importance: low

The maximum amount of random jitter relative to the credential’s lifetime that is added to the login refresh thread’s sleep time. Legal values are between 0 and 0.25 (25%) inclusive; a default value of 0.05 (5%) is used if no value is specified. Currently applies only to OAUTHBEARER.

Type: long
Default: 10000 (10 seconds)
Importance: low

The (optional) value in milliseconds for the maximum wait between login attempts to the external authentication provider. Login uses an exponential backoff algorithm with an initial wait based on the sasl.login.retry.backoff.ms setting and will double in wait length between attempts up to a maximum wait length specified by the sasl.login.retry.backoff.max.ms setting. Currently applies only to OAUTHBEARER.

Type: long
Default: 100
Importance: low

The (optional) value in milliseconds for the initial wait between login attempts to the external authentication provider. Login uses an exponential backoff algorithm with an initial wait based on the sasl.login.retry.backoff.ms setting and will double in wait length between attempts up to a maximum wait length specified by the sasl.login.retry.backoff.max.ms setting. Currently applies only to OAUTHBEARER.

Type: int
Default: 30
Importance: low

The (optional) value in seconds to allow for differences between the time of the OAuth/OIDC identity provider and the broker.

Type: list
Default: null
Importance: low

The (optional) comma-delimited setting for the broker to use to verify that the JWT was issued for one of the expected audiences. The JWT will be inspected for the standard OAuth "aud" claim and if this value is set, the broker will match the value from JWT’s "aud" claim to see if there is an exact match. If there is no match, the broker will reject the JWT and authentication will fail.

Type: string
Default: null
Importance: low

The (optional) setting for the broker to use to verify that the JWT was created by the expected issuer. The JWT will be inspected for the standard OAuth "iss" claim and if this value is set, the broker will match it exactly against what is in the JWT’s "iss" claim. If there is no match, the broker will reject the JWT and authentication will fail.

Type: long
Default: 3600000 (1 hour)
Importance: low

The (optional) value in milliseconds for the broker to wait between refreshing its JWKS (JSON Web Key Set) cache that contains the keys to verify the signature of the JWT.

Type: long
Default: 10000 (10 seconds)
Importance: low

The (optional) value in milliseconds for the maximum wait between attempts to retrieve the JWKS (JSON Web Key Set) from the external authentication provider. JWKS retrieval uses an exponential backoff algorithm with an initial wait based on the sasl.oauthbearer.jwks.endpoint.retry.backoff.ms setting and will double in wait length between attempts up to a maximum wait length specified by the sasl.oauthbearer.jwks.endpoint.retry.backoff.max.ms setting.

Type: long
Default: 100
Importance: low

The (optional) value in milliseconds for the initial wait between JWKS (JSON Web Key Set) retrieval attempts from the external authentication provider. JWKS retrieval uses an exponential backoff algorithm with an initial wait based on the sasl.oauthbearer.jwks.endpoint.retry.backoff.ms setting and will double in wait length between attempts up to a maximum wait length specified by the sasl.oauthbearer.jwks.endpoint.retry.backoff.max.ms setting.

Type: string
Default: scope
Importance: low

The OAuth claim for the scope is often named "scope", but this (optional) setting can provide a different name to use for the scope included in the JWT payload’s claims if the OAuth/OIDC provider uses a different name for that claim.

Type: string
Default: sub
Importance: low

The OAuth claim for the subject is often named "sub", but this (optional) setting can provide a different name to use for the subject included in the JWT payload’s claims if the OAuth/OIDC provider uses a different name for that claim.

Type: string
Default: null
Importance: low

A list of configurable creator classes each returning a provider implementing security algorithms. These classes should implement the org.apache.kafka.common.security.auth.SecurityProviderCreator interface.

Type: list
Default: null
Importance: low

A list of cipher suites. This is a named combination of authentication, encryption, MAC and key exchange algorithm used to negotiate the security settings for a network connection using TLS or SSL network protocol. By default all the available cipher suites are supported.

Type: string
Default: https
Importance: low

The endpoint identification algorithm to validate server hostname using server certificate.

Type: class
Default: null
Importance: low

The class of type org.apache.kafka.common.security.auth.SslEngineFactory to provide SSLEngine objects. Default value is org.apache.kafka.common.security.ssl.DefaultSslEngineFactory.

Type: string
Default: SunX509
Importance: low

The algorithm used by key manager factory for SSL connections. Default value is the key manager factory algorithm configured for the Java Virtual Machine.

Type: string
Default: null
Importance: low

The SecureRandom PRNG implementation to use for SSL cryptography operations.

Type: string
Default: PKIX
Importance: low

The algorithm used by trust manager factory for SSL connections. Default value is the trust manager factory algorithm configured for the Java Virtual Machine.

Type: class
Importance: high

Serializer class for key that implements the org.apache.kafka.common.serialization.Serializer interface.

Type: class
Importance: high

Serializer class for value that implements the org.apache.kafka.common.serialization.Serializer interface.

Type: list
Default: ""
Valid Values: non-null string
Importance: high

A list of host/port pairs to use for establishing the initial connection to the Kafka cluster. The client will make use of all servers irrespective of which servers are specified here for bootstrapping—this list only impacts the initial hosts used to discover the full set of servers. This list should be in the form host1:port1,host2:port2,…​. Since these servers are just used for the initial connection to discover the full cluster membership (which may change dynamically), this list need not contain the full set of servers (you may want more than one, though, in case a server is down).

Type: long
Default: 33554432
Valid Values: [0,…​]
Importance: high

The total bytes of memory the producer can use to buffer records waiting to be sent to the server. If records are sent faster than they can be delivered to the server the producer will block for max.block.ms after which it will throw an exception.

This setting should correspond roughly to the total memory the producer will use, but is not a hard bound since not all memory the producer uses is used for buffering. Some additional memory will be used for compression (if compression is enabled) as well as for maintaining in-flight requests.

Type: string
Default: none
Importance: high

The compression type for all data generated by the producer. The default is none (i.e. no compression). Valid values are none, gzip, snappy, lz4, or zstd. Compression is of full batches of data, so the efficacy of batching will also impact the compression ratio (more batching means better compression).

Type: int
Default: 2147483647
Valid Values: [0,…​,2147483647]
Importance: high

Setting a value greater than zero will cause the client to resend any record whose send fails with a potentially transient error. Note that this retry is no different than if the client resent the record upon receiving the error. Produce requests will be failed before the number of retries has been exhausted if the timeout configured by delivery.timeout.ms expires first before successful acknowledgement. Users should generally prefer to leave this config unset and instead use delivery.timeout.ms to control retry behavior.

Enabling idempotence requires this config value to be greater than 0. If conflicting configurations are set and idempotence is not explicitly enabled, idempotence is disabled.

Allowing retries while setting enable.idempotence to false and max.in.flight.requests.per.connection to 1 will potentially change the ordering of records because if two batches are sent to a single partition, and the first fails and is retried but the second succeeds, then the records in the second batch may appear first.

Type: password
Default: null
Importance: high

The password of the private key in the key store file or the PEM key specified in `ssl.keystore.key'. This is required for clients only if two-way authentication is configured.

Type: password
Default: null
Importance: high

Certificate chain in the format specified by 'ssl.keystore.type'. Default SSL engine factory supports only PEM format with a list of X.509 certificates.

Type: password
Default: null
Importance: high

Private key in the format specified by 'ssl.keystore.type'. Default SSL engine factory supports only PEM format with PKCS#8 keys. If the key is encrypted, key password must be specified using 'ssl.key.password'.

Type: string
Default: null
Importance: high

The location of the key store file. This is optional for client and can be used for two-way authentication for client.

Type: password
Default: null
Importance: high

The store password for the key store file. This is optional for client and only needed if 'ssl.keystore.location' is configured. Key store password is not supported for PEM format.

Type: password
Default: null
Importance: high

Trusted certificates in the format specified by 'ssl.truststore.type'. Default SSL engine factory supports only PEM format with X.509 certificates.

Type: string
Default: null
Importance: high

The location of the trust store file.

Type: password
Default: null
Importance: high

The password for the trust store file. If a password is not set, trust store file configured will still be used, but integrity checking is disabled. Trust store password is not supported for PEM format.

Type: int
Default: 16384
Valid Values: [0,…​]
Importance: medium

The producer will attempt to batch records together into fewer requests whenever multiple records are being sent to the same partition. This helps performance on both the client and the server. This configuration controls the default batch size in bytes.

No attempt will be made to batch records larger than this size.

Requests sent to brokers will contain multiple batches, one for each partition with data available to be sent.

A small batch size will make batching less common and may reduce throughput (a batch size of zero will disable batching entirely). A very large batch size may use memory a bit more wastefully as we will always allocate a buffer of the specified batch size in anticipation of additional records.

Note: This setting gives the upper bound of the batch size to be sent. If we have fewer than this many bytes accumulated for this partition, we will 'linger' for the linger.ms time waiting for more records to show up. This linger.ms setting defaults to 0, which means we’ll immediately send out a record even the accumulated batch size is under this batch.size setting.

Type: string
Default: use_all_dns_ips
Valid Values: [use_all_dns_ips, resolve_canonical_bootstrap_servers_only]
Importance: medium

Controls how the client uses DNS lookups. If set to use_all_dns_ips, connect to each returned IP address in sequence until a successful connection is established. After a disconnection, the next IP is used. Once all IPs have been used once, the client resolves the IP(s) from the hostname again (both the JVM and the OS cache DNS name lookups, however). If set to resolve_canonical_bootstrap_servers_only, resolve each bootstrap address into a list of canonical names. After the bootstrap phase, this behaves the same as use_all_dns_ips.

Type: string
Default: ""
Importance: medium

An id string to pass to the server when making requests. The purpose of this is to be able to track the source of requests beyond just ip/port by allowing a logical application name to be included in server-side request logging.

Type: long
Default: 540000 (9 minutes)
Importance: medium

Close idle connections after the number of milliseconds specified by this config.

Type: int
Default: 120000 (2 minutes)
Valid Values: [0,…​]
Importance: medium

An upper bound on the time to report success or failure after a call to send() returns. This limits the total time that a record will be delayed prior to sending, the time to await acknowledgement from the broker (if expected), and the time allowed for retriable send failures. The producer may report failure to send a record earlier than this config if either an unrecoverable error is encountered, the retries have been exhausted, or the record is added to a batch which reached an earlier delivery expiration deadline. The value of this config should be greater than or equal to the sum of request.timeout.ms and linger.ms.

Type: long
Default: 0
Valid Values: [0,…​]
Importance: medium

The producer groups together any records that arrive in between request transmissions into a single batched request. Normally this occurs only under load when records arrive faster than they can be sent out. However in some circumstances the client may want to reduce the number of requests even under moderate load. This setting accomplishes this by adding a small amount of artificial delay—that is, rather than immediately sending out a record, the producer will wait for up to the given delay to allow other records to be sent so that the sends can be batched together. This can be thought of as analogous to Nagle’s algorithm in TCP. This setting gives the upper bound on the delay for batching: once we get batch.size worth of records for a partition it will be sent immediately regardless of this setting, however if we have fewer than this many bytes accumulated for this partition we will 'linger' for the specified time waiting for more records to show up. This setting defaults to 0 (i.e. no delay). Setting linger.ms=5, for example, would have the effect of reducing the number of requests sent but would add up to 5ms of latency to records sent in the absence of load.

Type: long
Default: 60000 (1 minute)
Valid Values: [0,…​]
Importance: medium

The configuration controls how long the KafkaProducer’s `send(), partitionsFor(), initTransactions(), sendOffsetsToTransaction(), commitTransaction() and abortTransaction() methods will block. For send() this timeout bounds the total time waiting for both metadata fetch and buffer allocation (blocking in the user-supplied serializers or partitioner is not counted against this timeout). For partitionsFor() this timeout bounds the time spent waiting for metadata if it is unavailable. The transaction-related methods always block, but may timeout if the transaction coordinator could not be discovered or did not respond within the timeout.

Type: int
Default: 1048576
Valid Values: [0,…​]
Importance: medium

The maximum size of a request in bytes. This setting will limit the number of record batches the producer will send in a single request to avoid sending huge requests. This is also effectively a cap on the maximum uncompressed record batch size. Note that the server has its own cap on the record batch size (after compression if compression is enabled) which may be different from this.

Type: class
Default: org.apache.kafka.clients.producer.internals.DefaultPartitioner
Importance: medium

A class to use to determine which partition to be send to when produce the records. Available options are:

Type: int
Default: 32768 (32 kibibytes)
Valid Values: [-1,…​]
Importance: medium

The size of the TCP receive buffer (SO_RCVBUF) to use when reading data. If the value is -1, the OS default will be used.

Type: int
Default: 30000 (30 seconds)
Valid Values: [0,…​]
Importance: medium

The configuration controls the maximum amount of time the client will wait for the response of a request. If the response is not received before the timeout elapses the client will resend the request if necessary or fail the request if retries are exhausted. This should be larger than replica.lag.time.max.ms (a broker configuration) to reduce the possibility of message duplication due to unnecessary producer retries.

Type: class
Default: null
Importance: medium

The fully qualified name of a SASL client callback handler class that implements the AuthenticateCallbackHandler interface.

Type: password
Default: null
Importance: medium

JAAS login context parameters for SASL connections in the format used by JAAS configuration files. JAAS configuration file format is described here. The format for the value is: loginModuleClass controlFlag (optionName=optionValue)*;. For brokers, the config must be prefixed with listener prefix and SASL mechanism name in lower-case. For example, listener.name.sasl_ssl.scram-sha-256.sasl.jaas.config=com.example.ScramLoginModule required;.

Type: string
Default: null
Importance: medium

The Kerberos principal name that Kafka runs as. This can be defined either in Kafka’s JAAS config or in Kafka’s config.

Type: class
Default: null
Importance: medium

The fully qualified name of a SASL login callback handler class that implements the AuthenticateCallbackHandler interface. For brokers, login callback handler config must be prefixed with listener prefix and SASL mechanism name in lower-case. For example, listener.name.sasl_ssl.scram-sha-256.sasl.login.callback.handler.class=com.example.CustomScramLoginCallbackHandler.

Type: class
Default: null
Importance: medium

The fully qualified name of a class that implements the Login interface. For brokers, login config must be prefixed with listener prefix and SASL mechanism name in lower-case. For example, listener.name.sasl_ssl.scram-sha-256.sasl.login.class=com.example.CustomScramLogin.

Type: string
Default: GSSAPI
Importance: medium

SASL mechanism used for client connections. This may be any mechanism for which a security provider is available. GSSAPI is the default mechanism.

Type: string
Default: null
Importance: medium

The OAuth/OIDC provider URL from which the provider’s JWKS (JSON Web Key Set) can be retrieved. The URL can be HTTP(S)-based or file-based. If the URL is HTTP(S)-based, the JWKS data will be retrieved from the OAuth/OIDC provider via the configured URL on broker startup. All then-current keys will be cached on the broker for incoming requests. If an authentication request is received for a JWT that includes a "kid" header claim value that isn’t yet in the cache, the JWKS endpoint will be queried again on demand. However, the broker polls the URL every sasl.oauthbearer.jwks.endpoint.refresh.ms milliseconds to refresh the cache with any forthcoming keys before any JWT requests that include them are received. If the URL is file-based, the broker will load the JWKS file from a configured location on startup. In the event that the JWT includes a "kid" header value that isn’t in the JWKS file, the broker will reject the JWT and authentication will fail.

Type: string
Default: null
Importance: medium

The URL for the OAuth/OIDC identity provider. If the URL is HTTP(S)-based, it is the issuer’s token endpoint URL to which requests will be made to login based on the configuration in sasl.jaas.config. If the URL is file-based, it specifies a file containing an access token (in JWT serialized form) issued by the OAuth/OIDC identity provider to use for authorization.

Type: string
Default: PLAINTEXT
Importance: medium

Protocol used to communicate with brokers. Valid values are: PLAINTEXT, SSL, SASL_PLAINTEXT, SASL_SSL.

Type: int
Default: 131072 (128 kibibytes)
Valid Values: [-1,…​]
Importance: medium

The size of the TCP send buffer (SO_SNDBUF) to use when sending data. If the value is -1, the OS default will be used.

Type: long
Default: 30000 (30 seconds)
Importance: medium

The maximum amount of time the client will wait for the socket connection to be established. The connection setup timeout will increase exponentially for each consecutive connection failure up to this maximum. To avoid connection storms, a randomization factor of 0.2 will be applied to the timeout resulting in a random range between 20% below and 20% above the computed value.

Type: long
Default: 10000 (10 seconds)
Importance: medium

The amount of time the client will wait for the socket connection to be established. If the connection is not built before the timeout elapses, clients will close the socket channel.

Type: list
Default: TLSv1.2,TLSv1.3
Importance: medium

The list of protocols enabled for SSL connections. The default is 'TLSv1.2,TLSv1.3' when running with Java 11 or newer, 'TLSv1.2' otherwise. With the default value for Java 11, clients and servers will prefer TLSv1.3 if both support it and fallback to TLSv1.2 otherwise (assuming both support at least TLSv1.2). This default should be fine for most cases. Also see the config documentation for ssl.protocol.

Type: string
Default: JKS
Importance: medium

The file format of the key store file. This is optional for client.

Type: string
Default: TLSv1.3
Importance: medium

The SSL protocol used to generate the SSLContext. The default is 'TLSv1.3' when running with Java 11 or newer, 'TLSv1.2' otherwise. This value should be fine for most use cases. Allowed values in recent JVMs are 'TLSv1.2' and 'TLSv1.3'. 'TLS', 'TLSv1.1', 'SSL', 'SSLv2' and 'SSLv3' may be supported in older JVMs, but their usage is discouraged due to known security vulnerabilities. With the default value for this config and 'ssl.enabled.protocols', clients will downgrade to 'TLSv1.2' if the server does not support 'TLSv1.3'. If this config is set to 'TLSv1.2', clients will not use 'TLSv1.3' even if it is one of the values in ssl.enabled.protocols and the server only supports 'TLSv1.3'.

Type: string
Default: null
Importance: medium

The name of the security provider used for SSL connections. Default value is the default security provider of the JVM.

Type: string
Default: JKS
Importance: medium

The file format of the trust store file.

Type: string
Default: all
Valid Values: [all, -1, 0, 1]
Importance: low

The number of acknowledgments the producer requires the leader to have received before considering a request complete. This controls the durability of records that are sent. The following settings are allowed:

Type: boolean
Default: true
Importance: low

When set to 'true', the producer will ensure that exactly one copy of each message is written in the stream. If 'false', producer retries due to broker failures, etc., may write duplicates of the retried message in the stream. Note that enabling idempotence requires max.in.flight.requests.per.connection to be less than or equal to 5 (with message ordering preserved for any allowable value), retries to be greater than 0, and acks must be 'all'.

Idempotence is enabled by default if no conflicting configurations are set. If conflicting configurations are set and idempotence is not explicitly enabled, idempotence is disabled. If idempotence is explicitly enabled and conflicting configurations are set, a ConfigException is thrown.

Type: list
Default: ""
Valid Values: non-null string
Importance: low

A list of classes to use as interceptors. Implementing the org.apache.kafka.clients.producer.ProducerInterceptor interface allows you to intercept (and possibly mutate) the records received by the producer before they are published to the Kafka cluster. By default, there are no interceptors.

Type: int
Default: 5
Valid Values: [1,…​]
Importance: low

The maximum number of unacknowledged requests the client will send on a single connection before blocking. Note that if this config is set to be greater than 1 and enable.idempotence is set to false, there is a risk of message re-ordering after a failed send due to retries (i.e., if retries are enabled). Additionally, enabling idempotence requires this config value to be less than or equal to 5. If conflicting configurations are set and idempotence is not explicitly enabled, idempotence is disabled.

Type: long
Default: 300000 (5 minutes)
Valid Values: [0,…​]
Importance: low

The period of time in milliseconds after which we force a refresh of metadata even if we haven’t seen any partition leadership changes to proactively discover any new brokers or partitions.

Type: long
Default: 300000 (5 minutes)
Valid Values: [5000,…​]
Importance: low

Controls how long the producer will cache metadata for a topic that’s idle. If the elapsed time since a topic was last produced to exceeds the metadata idle duration, then the topic’s metadata is forgotten and the next access to it will force a metadata fetch request.

Type: list
Default: ""
Valid Values: non-null string
Importance: low

A list of classes to use as metrics reporters. Implementing the org.apache.kafka.common.metrics.MetricsReporter interface allows plugging in classes that will be notified of new metric creation. The JmxReporter is always included to register JMX statistics.

Type: int
Default: 2
Valid Values: [1,…​]
Importance: low

The number of samples maintained to compute metrics.

Type: string
Default: INFO
Valid Values: [INFO, DEBUG, TRACE]
Importance: low

The highest recording level for metrics.

Type: long
Default: 30000 (30 seconds)
Valid Values: [0,…​]
Importance: low

The window of time a metrics sample is computed over.

Type: long
Default: 1000 (1 second)
Valid Values: [0,…​]
Importance: low

The maximum amount of time in milliseconds to wait when reconnecting to a broker that has repeatedly failed to connect. If provided, the backoff per host will increase exponentially for each consecutive connection failure, up to this maximum. After calculating the backoff increase, 20% random jitter is added to avoid connection storms.

Type: long
Default: 50
Valid Values: [0,…​]
Importance: low

The base amount of time to wait before attempting to reconnect to a given host. This avoids repeatedly connecting to a host in a tight loop. This backoff applies to all connection attempts by the client to a broker.

Type: long
Default: 100
Valid Values: [0,…​]
Importance: low

The amount of time to wait before attempting to retry a failed request to a given topic partition. This avoids repeatedly sending requests in a tight loop under some failure scenarios.

Type: string
Default: /usr/bin/kinit
Importance: low

Kerberos kinit command path.

Type: long
Default: 60000
Importance: low

Login thread sleep time between refresh attempts.

Type: double
Default: 0.05
Importance: low

Percentage of random jitter added to the renewal time.

Type: double
Default: 0.8
Importance: low

Login thread will sleep until the specified window factor of time from last refresh to ticket’s expiry has been reached, at which time it will try to renew the ticket.

Type: int
Default: null
Importance: low

The (optional) value in milliseconds for the external authentication provider connection timeout. Currently applies only to OAUTHBEARER.

Type: int
Default: null
Importance: low

The (optional) value in milliseconds for the external authentication provider read timeout. Currently applies only to OAUTHBEARER.

Type: short
Default: 300
Valid Values: [0,…​,3600]
Importance: low

The amount of buffer time before credential expiration to maintain when refreshing a credential, in seconds. If a refresh would otherwise occur closer to expiration than the number of buffer seconds then the refresh will be moved up to maintain as much of the buffer time as possible. Legal values are between 0 and 3600 (1 hour); a default value of 300 (5 minutes) is used if no value is specified. This value and sasl.login.refresh.min.period.seconds are both ignored if their sum exceeds the remaining lifetime of a credential. Currently applies only to OAUTHBEARER.

Type: short
Default: 60
Valid Values: [0,…​,900]
Importance: low

The desired minimum time for the login refresh thread to wait before refreshing a credential, in seconds. Legal values are between 0 and 900 (15 minutes); a default value of 60 (1 minute) is used if no value is specified. This value and sasl.login.refresh.buffer.seconds are both ignored if their sum exceeds the remaining lifetime of a credential. Currently applies only to OAUTHBEARER.

Type: double
Default: 0.8
Valid Values: [0.5,…​,1.0]
Importance: low

Login refresh thread will sleep until the specified window factor relative to the credential’s lifetime has been reached, at which time it will try to refresh the credential. Legal values are between 0.5 (50%) and 1.0 (100%) inclusive; a default value of 0.8 (80%) is used if no value is specified. Currently applies only to OAUTHBEARER.

Type: double
Default: 0.05
Valid Values: [0.0,…​,0.25]
Importance: low

The maximum amount of random jitter relative to the credential’s lifetime that is added to the login refresh thread’s sleep time. Legal values are between 0 and 0.25 (25%) inclusive; a default value of 0.05 (5%) is used if no value is specified. Currently applies only to OAUTHBEARER.