zookeeper.connect

Zookeeper host string

string

high

advertised.host.name

DEPRECATED: only used when advertised.listeners or listeners are not set. Use advertised.listeners instead. Hostname to publish to ZooKeeper for clients to use. In IaaS environments, this may need to be different from the interface to which the broker binds. If this is not set, it will use the value for host.name if configured. Otherwise it will use the value returned from java.net.InetAddress.getCanonicalHostName().

string

null

high

advertised.listeners

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.

string

null

high

advertised.port

DEPRECATED: only used when advertised.listeners or listeners are not set. Use advertised.listeners instead. The port to publish to ZooKeeper for clients to use. In IaaS environments, this may need to be different from the port to which the broker binds. If this is not set, it will publish the same port that the broker binds to.

int

null

high

auto.create.topics.enable

Enable auto creation of topic on the server

boolean

true

high

auto.leader.rebalance.enable

Enables auto leader balancing. A background thread checks and triggers leader balance if required at regular intervals

boolean

true

high

background.threads

The number of threads to use for various background processing tasks

int

10

[1,…​]

high

broker.id

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.

int

-1

high

compression.type

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

string

producer

high

delete.topic.enable

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

boolean

true

high

host.name

DEPRECATED: only used when listeners is not set. Use listeners instead. hostname of broker. If this is set, it will only bind to this address. If this is not set, it will bind to all interfaces

string

""

high

leader.imbalance.check.interval.seconds

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

long

300

high

leader.imbalance.per.broker.percentage

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.

int

10

high

listeners

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. 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

string

null

high

log.dir

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

string

/tmp/kafka-logs

high

log.dirs

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

string

null

high

log.flush.interval.messages

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

long

9223372036854775807

[1,…​]

high

log.flush.interval.ms

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

long

null

high

log.flush.offset.checkpoint.interval.ms

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

int

60000

[0,…​]

high

log.flush.scheduler.interval.ms

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

long

9223372036854775807

high

log.flush.start.offset.checkpoint.interval.ms

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

int

60000

[0,…​]

high

log.retention.bytes

The maximum size of the log before deleting it

long

-1

high

log.retention.hours

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

int

168

high

log.retention.minutes

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

int

null

high

log.retention.ms

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

long

null

high

log.roll.hours

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

int

168

[1,…​]

high

log.roll.jitter.hours

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

int

0

[0,…​]

high

log.roll.jitter.ms

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

long

null

high

log.roll.ms

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

long

null

high

log.segment.bytes

The maximum size of a single log file

int

1073741824

[14,…​]

high

log.segment.delete.delay.ms

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

long

60000

[0,…​]

high

message.max.bytes

The largest record batch size allowed by Kafka. If this is increased and there are consumers older than 0.10.2, the consumers' fetch size must also be increased so that the 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.

int

1000012

[0,…​]

high

min.insync.replicas

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.

int

1

[1,…​]

high

num.io.threads

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

int

8

[1,…​]

high

num.network.threads

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

int

3

[1,…​]

high

num.recovery.threads.per.data.dir

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

int

1

[1,…​]

high

num.replica.alter.log.dirs.threads

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

int

null

high

num.replica.fetchers

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.

int

1

high

offset.metadata.max.bytes

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

int

4096

high

offsets.commit.required.acks

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

short

-1

high

offsets.commit.timeout.ms

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.

int

5000

[1,…​]

high

offsets.load.buffer.size

Batch size for reading from the offsets segments when loading offsets into the cache.

int

5242880

[1,…​]

high

offsets.retention.check.interval.ms

Frequency at which to check for stale offsets

long

600000

[1,…​]

high

offsets.retention.minutes

Offsets older than this retention period will be discarded

int

10080

[1,…​]

high

offsets.topic.compression.codec

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

int

0

high

offsets.topic.num.partitions

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

int

50

[1,…​]

high

offsets.topic.replication.factor

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.

short

3

[1,…​]

high

offsets.topic.segment.bytes

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

int

104857600

[1,…​]

high

port

DEPRECATED: only used when listeners is not set. Use listeners instead. the port to listen and accept connections on

int

9092

high

queued.max.requests

The number of queued requests allowed before blocking the network threads

int

500

[1,…​]

high

quota.consumer.default

DEPRECATED: Used only when dynamic default quotas are not configured for <user, <client-id> or <user, client-id> in Zookeeper. Any consumer distinguished by clientId/consumer group will get throttled if it fetches more bytes than this value per-second

long

9223372036854775807

[1,…​]

high

quota.producer.default

DEPRECATED: Used only when dynamic default quotas are not configured for <user>, <client-id> or <user, client-id> in Zookeeper. Any producer distinguished by clientId will get throttled if it produces more bytes than this value per-second

long

9223372036854775807

[1,…​]

high

replica.fetch.min.bytes

Minimum bytes expected for each fetch response. If not enough bytes, wait up to replicaMaxWaitTimeMs

int

1

high

replica.fetch.wait.max.ms

max 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

int

500

high

replica.high.watermark.checkpoint.interval.ms

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

long

5000

high

replica.lag.time.max.ms

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

long

10000

high

replica.socket.receive.buffer.bytes

The socket receive buffer for network requests

int

65536

high

replica.socket.timeout.ms

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

int

30000

high

request.timeout.ms

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.

int

30000

high

socket.receive.buffer.bytes

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

int

102400

high

socket.request.max.bytes

The maximum number of bytes in a socket request

int

104857600

[1,…​]

high

socket.send.buffer.bytes

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

int

102400

high

transaction.max.timeout.ms

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.

int

900000

[1,…​]

high

transaction.state.log.load.buffer.size

Batch size for reading from the transaction log segments when loading producer ids and transactions into the cache.

int

5242880

[1,…​]

high

transaction.state.log.min.isr

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

int

2

[1,…​]

high

transaction.state.log.num.partitions

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

int

50

[1,…​]

high

transaction.state.log.replication.factor

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.

short

3

[1,…​]

high

transaction.state.log.segment.bytes

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

int

104857600

[1,…​]

high

transactional.id.expiration.ms

The maximum amount of time in ms that the transaction coordinator will wait before proactively expire a producer’s transactional id without receiving any transaction status updates from it.

int

604800000

[1,…​]

high

unclean.leader.election.enable

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

boolean

false

high

zookeeper.connection.timeout.ms

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

int

null

high

zookeeper.max.in.flight.requests

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

int

10

[1,…​]

high

zookeeper.session.timeout.ms

Zookeeper session timeout

int

6000

high

zookeeper.set.acl

Set client to use secure ACLs

boolean

false

high

broker.id.generation.enable

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

boolean

true

medium

broker.rack

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

string

null

medium

connections.max.idle.ms

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

long

600000

medium

controlled.shutdown.enable

Enable controlled shutdown of the server

boolean

true

medium

controlled.shutdown.max.retries

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

int

3

medium

controlled.shutdown.retry.backoff.ms

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.

long

5000

medium

controller.socket.timeout.ms

The socket timeout for controller-to-broker channels

int

30000

medium

default.replication.factor

default replication factors for automatically created topics

int

1

medium

delegation.token.expiry.time.ms

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

long

86400000

[1,…​]

medium

delegation.token.master.key

Master/secret key to generate and verify delegation tokens. 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.

password

null

medium

delegation.token.max.lifetime.ms

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

long

604800000

[1,…​]

medium

delete.records.purgatory.purge.interval.requests

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

int

1

medium

fetch.purgatory.purge.interval.requests

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

int

1000

medium

group.initial.rebalance.delay.ms

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.

int

3000

medium

group.max.session.timeout.ms

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.

int

300000

medium

group.min.session.timeout.ms

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.

int

6000

medium

inter.broker.listener.name

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.

string

null

medium

inter.broker.protocol.version

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.

string

2.0-IV1

medium

log.cleaner.backoff.ms

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

long

15000

[0,…​]

medium

log.cleaner.dedupe.buffer.size

The total memory used for log deduplication across all cleaner threads

long

134217728

medium

log.cleaner.delete.retention.ms

How long are delete records retained?

long

86400000

medium

log.cleaner.enable

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.

boolean

true

medium

log.cleaner.io.buffer.load.factor

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

double

0.9

medium

log.cleaner.io.buffer.size

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

int

524288

[0,…​]

medium

log.cleaner.io.max.bytes.per.second

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

double

1.7976931348623157E308

medium

log.cleaner.min.cleanable.ratio

The minimum ratio of dirty log to total log for a log to eligible for cleaning

double

0.5

medium

log.cleaner.min.compaction.lag.ms

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

long

0

medium

log.cleaner.threads

The number of background threads to use for log cleaning

int

1

[0,…​]

medium

log.cleanup.policy

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

list

delete

[compact, delete]

medium

log.index.interval.bytes

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

int

4096

[0,…​]

medium

log.index.size.max.bytes

The maximum size in bytes of the offset index

int

10485760

[4,…​]

medium

log.message.format.version

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.

string

2.0-IV1

medium

log.message.timestamp.difference.max.ms

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.

long

9223372036854775807

medium

log.message.timestamp.type

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

string

CreateTime

[CreateTime, LogAppendTime]

medium

log.preallocate

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

boolean

false

medium

log.retention.check.interval.ms

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

long

300000

[1,…​]

medium

max.connections.per.ip

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

int

2147483647

[0,…​]

medium

max.connections.per.ip.overrides

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"

string

""

medium

max.incremental.fetch.session.cache.slots

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

int

1000

[0,…​]

medium

num.partitions

The default number of log partitions per topic

int

1

[1,…​]

medium

password.encoder.old.secret

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.

password

null

medium

password.encoder.secret

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

password

null

medium

principal.builder.class

The fully qualified name of a class that implements the KafkaPrincipalBuilder interface, which is used to build the KafkaPrincipal object used during authorization. This config also supports the deprecated PrincipalBuilder interface which was previously used for client authentication over SSL. If no principal builder is defined, the default behavior depends on the security protocol in use. For SSL authentication, the principal name will be 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.

class

null

medium

producer.purgatory.purge.interval.requests

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

int

1000

medium

queued.max.request.bytes

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

long

-1

medium

replica.fetch.backoff.ms

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

int

1000

[0,…​]

medium

replica.fetch.max.bytes

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).

int

1048576

[0,…​]

medium

replica.fetch.response.max.bytes

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).

int

10485760

[0,…​]

medium

reserved.broker.max.id

Max number that can be used for a broker.id

int

1000

[0,…​]

medium

sasl.client.callback.handler.class

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

class

null

medium

sasl.enabled.mechanisms

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.

list

GSSAPI

medium

sasl.jaas.config

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;

password

null

medium

sasl.kerberos.kinit.cmd

Kerberos kinit command path.

string

/usr/bin/kinit

medium

sasl.kerberos.min.time.before.relogin

Login thread sleep time between refresh attempts.

long

60000

medium

sasl.kerberos.principal.to.local.rules

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_authz[ security authorization and acls]. Note that this configuration is ignored if an extension of KafkaPrincipalBuilder is provided by the principal.builder.class configuration.

list

DEFAULT

medium

sasl.kerberos.service.name

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

string

null

medium

sasl.kerberos.ticket.renew.jitter

Percentage of random jitter added to the renewal time.

double

0.05

medium

sasl.kerberos.ticket.renew.window.factor

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.

double

0.8

medium

sasl.login.callback.handler.class

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

class

null

medium

sasl.login.class

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

class

null

medium

sasl.login.refresh.buffer.seconds

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.

short

300

medium

sasl.login.refresh.min.period.seconds

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.

short

60

medium

sasl.login.refresh.window.factor

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.

double

0.8

medium

sasl.login.refresh.window.jitter

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.

double

0.05

medium

sasl.mechanism.inter.broker.protocol

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

string

GSSAPI

medium

sasl.server.callback.handler.class

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.

class

null

medium

security.inter.broker.protocol

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.

string

PLAINTEXT

medium

ssl.cipher.suites

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.

list

""

medium

ssl.client.auth

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

string

none

[required, requested, none]

medium

ssl.enabled.protocols

The list of protocols enabled for SSL connections.

list

TLSv1.2,TLSv1.1,TLSv1

medium

ssl.key.password

The password of the private key in the key store file. This is optional for client.

password

null

medium

ssl.keymanager.algorithm

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

string

SunX509

medium

ssl.keystore.location

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

string

null

medium

ssl.keystore.password

The store password for the key store file. This is optional for client and only needed if ssl.keystore.location is configured.

password

null

medium

ssl.keystore.type

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

string

JKS

medium

ssl.protocol

The SSL protocol used to generate the SSLContext. Default setting is TLS, which is fine for most cases. Allowed values in recent JVMs are TLS, TLSv1.1 and TLSv1.2. SSL, SSLv2 and SSLv3 may be supported in older JVMs, but their usage is discouraged due to known security vulnerabilities.

string

TLS

medium

ssl.provider

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

string

null

medium

ssl.trustmanager.algorithm

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

string

PKIX

medium

ssl.truststore.location

The location of the trust store file.

string

null

medium

ssl.truststore.password

The password for the trust store file. If a password is not set access to the truststore is still available, but integrity checking is disabled.

password

null

medium

ssl.truststore.type

The file format of the trust store file.

string

JKS

medium

alter.config.policy.class.name

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

class

null

low

alter.log.dirs.replication.quota.window.num

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

int

11

[1,…​]

low

alter.log.dirs.replication.quota.window.size.seconds

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

int

1

[1,…​]

low

authorizer.class.name

The authorizer class that should be used for authorization

string

""

low

client.quota.callback.class

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.

class

null

low

create.topic.policy.class.name

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

class

null

low

delegation.token.expiry.check.interval.ms

Scan interval to remove expired delegation tokens.

long

3600000

[1,…​]

low

listener.security.protocol.map

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).

string

PLAINTEXT:PLAINTEXT,SSL:SSL,SASL_PLAINTEXT:SASL_PLAINTEXT,SASL_SSL:SASL_SSL

low

log.message.downconversion.enable

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.

boolean

true

low

metric.reporters

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.

list

""

low

metrics.num.samples

The number of samples maintained to compute metrics.

int

2

[1,…​]

low

metrics.recording.level

The highest recording level for metrics.

string

INFO

low

metrics.sample.window.ms

The window of time a metrics sample is computed over.

long

30000

[1,…​]

low

password.encoder.cipher.algorithm

The Cipher algorithm used for encoding dynamically configured passwords.

string

AES/CBC/PKCS5Padding

low

password.encoder.iterations

The iteration count used for encoding dynamically configured passwords.

int

4096

[1024,…​]

low

password.encoder.key.length

The key length used for encoding dynamically configured passwords.

int

128

[8,…​]

low

password.encoder.keyfactory.algorithm

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

string

null

low

quota.window.num

The number of samples to retain in memory for client quotas

int

11

[1,…​]

low

quota.window.size.seconds

The time span of each sample for client quotas

int

1

[1,…​]

low

replication.quota.window.num

The number of samples to retain in memory for replication quotas

int

11

[1,…​]

low

replication.quota.window.size.seconds

The time span of each sample for replication quotas

int

1

[1,…​]

low

ssl.endpoint.identification.algorithm

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

string

https

low

ssl.secure.random.implementation

The SecureRandom PRNG implementation to use for SSL cryptography operations.

string

null

low

transaction.abort.timed.out.transaction.cleanup.interval.ms

The interval at which to rollback transactions that have timed out

int

60000

[1,…​]

low

transaction.remove.expired.transaction.cleanup.interval.ms

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

int

3600000

[1,…​]

low

zookeeper.sync.time.ms

How far a ZK follower can be behind a ZK leader

int

2000

low

cleanup.policy

A string that is either "delete" or "compact". 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 #compaction[log compaction] on the topic.

list

delete

[compact, delete]

log.cleanup.policy

medium

compression.type

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

string

producer

[uncompressed, snappy, lz4, gzip, producer]

compression.type

medium

delete.retention.ms

The amount of time to retain delete tombstone markers for #compaction[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).

long

86400000

[0,…​]

log.cleaner.delete.retention.ms

medium

file.delete.delay.ms

The time to wait before deleting a file from the filesystem

long

60000

[0,…​]

log.segment.delete.delay.ms

medium

flush.messages

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 #topicconfigs[the per-topic configuration section]).

long

9223372036854775807

[0,…​]

log.flush.interval.messages

medium

flush.ms

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.

long

9223372036854775807

[0,…​]

log.flush.interval.ms

medium

follower.replication.throttled.replicas

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.

list

""

[partitionId],[brokerId]:[partitionId],[brokerId]:…​

follower.replication.throttled.replicas

medium

index.interval.bytes

This setting controls how frequently Kafka adds an index entry to it’s 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.

int

4096

[0,…​]

log.index.interval.bytes

medium

leader.replication.throttled.replicas

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.

list

""

[partitionId],[brokerId]:[partitionId],[brokerId]:…​

leader.replication.throttled.replicas

medium

max.message.bytes

The largest record batch size allowed by Kafka. If this is increased and there are consumers older than 0.10.2, the consumers' fetch size must also be increased so that the 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.

int

1000012

[0,…​]

message.max.bytes

medium

message.format.version

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.

string

2.0-IV1

log.message.format.version

medium

message.timestamp.difference.max.ms

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.

long

9223372036854775807

[0,…​]

log.message.timestamp.difference.max.ms

medium

message.timestamp.type

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

string

CreateTime

[CreateTime, LogAppendTime]

log.message.timestamp.type

medium

min.cleanable.dirty.ratio

This configuration controls how frequently the log compactor will attempt to clean the log (assuming #compaction[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.

double

0.5

[0,…​,1]

log.cleaner.min.cleanable.ratio

medium

min.compaction.lag.ms

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

long

0

[0,…​]

log.cleaner.min.compaction.lag.ms

medium

min.insync.replicas

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.

int

1

[1,…​]

min.insync.replicas

medium

preallocate

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

boolean

false

log.preallocate

medium

retention.bytes

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.

long

-1

log.retention.bytes

medium

retention.ms

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.

long

604800000

log.retention.ms

medium

segment.bytes

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.

int

1073741824

[14,…​]

log.segment.bytes

medium

segment.index.bytes

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.

int

10485760

[0,…​]

log.index.size.max.bytes

medium

segment.jitter.ms

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

long

0

[0,…​]

log.roll.jitter.ms

medium

segment.ms

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.

long

604800000

[1,…​]

log.roll.ms

medium

unclean.leader.election.enable

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.

boolean

false

unclean.leader.election.enable

medium

message.downconversion.enable

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.

boolean

true

log.message.downconversion.enable

low

key.deserializer

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

class

high

value.deserializer

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

class

high

bootstrap.servers

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).

list

""

non-null value

high

fetch.min.bytes

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.

int

1

[0,…​]

high

group.id

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.

string

""

high

heartbeat.interval.ms

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.

int

3000

high

max.partition.fetch.bytes

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.

int

1048576

[0,…​]

high

session.timeout.ms

The timeout used to detect consumer failures when using Kafka’s group management facility. The consumer 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 consumer 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.

int

10000

high

ssl.key.password

The password of the private key in the key store file. This is optional for client.

password

null

high

ssl.keystore.location

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

string

null

high

ssl.keystore.password

The store password for the key store file. This is optional for client and only needed if ssl.keystore.location is configured.

password

null

high

ssl.truststore.location

The location of the trust store file.

string

null

high

ssl.truststore.password

The password for the trust store file. If a password is not set access to the truststore is still available, but integrity checking is disabled.

password

null

high

auto.offset.reset

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):

string

latest

[latest, earliest, none]

medium

connections.max.idle.ms

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

long

540000

medium

default.api.timeout.ms

Specifies the timeout (in milliseconds) for consumer APIs that could block. This configuration is used as the default timeout for all consumer operations that do not explicitly accept a timeout parameter.

int

60000

[0,…​]

medium

enable.auto.commit

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

boolean

true

medium

exclude.internal.topics

Whether records from internal topics (such as offsets) should be exposed to the consumer. If set to true the only way to receive records from an internal topic is subscribing to it.

boolean

true

medium

fetch.max.bytes

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.

int

52428800

[0,…​]

medium

isolation.level

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</mode> the seekToEnd method will return the LSO

string

read_uncommitted

[read_committed, read_uncommitted]

medium

max.poll.interval.ms

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.

int

300000

[1,…​]

medium

max.poll.records

The maximum number of records returned in a single call to poll().

int

500

[1,…​]

medium

partition.assignment.strategy

The class name of the partition assignment strategy that the client will use to distribute partition ownership amongst consumer instances when group management is used

list

class org.apache.kafka.clients.consumer.RangeAssignor

non-null value

medium

receive.buffer.bytes

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.

int

65536

[-1,…​]

medium

request.timeout.ms

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.

int

30000

[0,…​]

medium

sasl.client.callback.handler.class

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

class

null

medium

sasl.jaas.config

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;

password

null

medium

sasl.kerberos.service.name

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

string

null

medium

sasl.login.callback.handler.class

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

class

null

medium

sasl.login.class

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

class

null

medium

sasl.mechanism

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

string

GSSAPI

medium

security.protocol

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

string

PLAINTEXT

medium

send.buffer.bytes

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.

int

131072

[-1,…​]

medium

ssl.enabled.protocols

The list of protocols enabled for SSL connections.

list

TLSv1.2,TLSv1.1,TLSv1

medium

ssl.keystore.type

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

string

JKS

medium

ssl.protocol

The SSL protocol used to generate the SSLContext. Default setting is TLS, which is fine for most cases. Allowed values in recent JVMs are TLS, TLSv1.1 and TLSv1.2. SSL, SSLv2 and SSLv3 may be supported in older JVMs, but their usage is discouraged due to known security vulnerabilities.

string

TLS

medium

ssl.provider

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

string

null

medium

ssl.truststore.type

The file format of the trust store file.

string

JKS

medium

auto.commit.interval.ms

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

int

5000

[0,…​]

low

check.crcs

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.

boolean

true

low

client.id

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.

string

""

low

fetch.max.wait.ms

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.

int

500

[0,…​]

low

interceptor.classes

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.

list

""

non-null value

low

metadata.max.age.ms

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.

long

300000

[0,…​]

low

metric.reporters

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.

list

""

non-null value

low

metrics.num.samples

The number of samples maintained to compute metrics.

int

2

[1,…​]

low

metrics.recording.level

The highest recording level for metrics.

string

INFO

[INFO, DEBUG]

low

metrics.sample.window.ms

The window of time a metrics sample is computed over.

long

30000

[0,…​]

low

reconnect.backoff.max.ms

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.

long

1000

[0,…​]

low

reconnect.backoff.ms

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.

long

50

[0,…​]

low

retry.backoff.ms

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.

long

100

[0,…​]

low

sasl.kerberos.kinit.cmd

Kerberos kinit command path.

string

/usr/bin/kinit

low

sasl.kerberos.min.time.before.relogin

Login thread sleep time between refresh attempts.

long

60000

low

sasl.kerberos.ticket.renew.jitter

Percentage of random jitter added to the renewal time.

double

0.05

low

sasl.kerberos.ticket.renew.window.factor

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.

double

0.8

low

sasl.login.refresh.buffer.seconds

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.

short

300

[0,…​,3600]

low

sasl.login.refresh.min.period.seconds

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.

short

60

[0,…​,900]

low

sasl.login.refresh.window.factor

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.

double

0.8

[0.5,…​,1.0]

low

sasl.login.refresh.window.jitter

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.

double

0.05

[0.0,…​,0.25]

low

ssl.cipher.suites

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.

list

null

low

ssl.endpoint.identification.algorithm

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

string

https

low

ssl.keymanager.algorithm

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

string

SunX509

low

ssl.secure.random.implementation

The SecureRandom PRNG implementation to use for SSL cryptography operations.

string

null

low

ssl.trustmanager.algorithm

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

string

PKIX

low

key.serializer

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

class

high

value.serializer

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

class

high

acks

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:

string

1

[all, -1, 0, 1]

high

bootstrap.servers

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).

list

""

non-null value

high

buffer.memory

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.

long

33554432

[0,…​]

high

compression.type

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

string

none

high

retries

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. Allowing retries without setting 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.

int

0

[0,…​,2147483647]

high

ssl.key.password

The password of the private key in the key store file. This is optional for client.

password

null

high

ssl.keystore.location

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

string

null

high

ssl.keystore.password

The store password for the key store file. This is optional for client and only needed if ssl.keystore.location is configured.

password

null

high

ssl.truststore.location

The location of the trust store file.

string

null

high

ssl.truststore.password

The password for the trust store file. If a password is not set access to the truststore is still available, but integrity checking is disabled.

password

null

high

batch.size

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.

int

16384

[0,…​]

medium

client.id

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.

string

""

medium

connections.max.idle.ms

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

long

540000

medium

linger.ms

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.

long

0

[0,…​]

medium

max.block.ms

The configuration controls how long KafkaProducer.send() and KafkaProducer.partitionsFor() will block.These methods can be blocked either because the buffer is full or metadata unavailable.Blocking in the user-supplied serializers or partitioner will not be counted against this timeout.

long

60000

[0,…​]

medium

max.request.size

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 record batch size. Note that the server has its own cap on record batch size which may be different from this.

int

1048576

[0,…​]

medium

partitioner.class

Partitioner class that implements the org.apache.kafka.clients.producer.Partitioner interface.

class

org.apache.kafka.clients.producer.internals.DefaultPartitioner

medium

receive.buffer.bytes

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.

int

32768

[-1,…​]

medium

request.timeout.ms

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.

int

30000

[0,…​]

medium

sasl.client.callback.handler.class

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

class

null

medium

sasl.jaas.config

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;

password

null

medium

sasl.kerberos.service.name

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

string

null

medium

sasl.login.callback.handler.class

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

class

null

medium

sasl.login.class

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

class

null

medium

sasl.mechanism

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

string

GSSAPI

medium

security.protocol

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

string

PLAINTEXT

medium

send.buffer.bytes

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.

int

131072

[-1,…​]

medium

ssl.enabled.protocols

The list of protocols enabled for SSL connections.

list

TLSv1.2,TLSv1.1,TLSv1

medium

ssl.keystore.type

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

string

JKS

medium

ssl.protocol

The SSL protocol used to generate the SSLContext. Default setting is TLS, which is fine for most cases. Allowed values in recent JVMs are TLS, TLSv1.1 and TLSv1.2. SSL, SSLv2 and SSLv3 may be supported in older JVMs, but their usage is discouraged due to known security vulnerabilities.

string

TLS

medium

ssl.provider

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

string

null

medium

ssl.truststore.type

The file format of the trust store file.

string

JKS

medium

enable.idempotence

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, retries to be greater than 0 and acks must be 'all'. If these values are not explicitly set by the user, suitable values will be chosen. If incompatible values are set, a ConfigException will be thrown.

boolean

false

low

interceptor.classes

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.

list

""

non-null value

low

max.in.flight.requests.per.connection

The maximum number of unacknowledged requests the client will send on a single connection before blocking. Note that if this setting is set to be greater than 1 and there are failed sends, there is a risk of message re-ordering due to retries (i.e., if retries are enabled).

int

5

[1,…​]

low

metadata.max.age.ms

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.

long

300000

[0,…​]

low

metric.reporters

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.

list

""

non-null value

low

metrics.num.samples

The number of samples maintained to compute metrics.

int

2

[1,…​]

low

metrics.recording.level

The highest recording level for metrics.

string

INFO

[INFO, DEBUG]

low

metrics.sample.window.ms

The window of time a metrics sample is computed over.

long

30000

[0,…​]

low

reconnect.backoff.max.ms

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.

long

1000

[0,…​]

low

reconnect.backoff.ms

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.

long

50

[0,…​]

low

retry.backoff.ms

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.

long

100

[0,…​]

low

sasl.kerberos.kinit.cmd

Kerberos kinit command path.

string

/usr/bin/kinit

low

sasl.kerberos.min.time.before.relogin

Login thread sleep time between refresh attempts.

long

60000

low

sasl.kerberos.ticket.renew.jitter

Percentage of random jitter added to the renewal time.

double

0.05

low

sasl.kerberos.ticket.renew.window.factor

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.

double

0.8

low

sasl.login.refresh.buffer.seconds

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.

short

300

[0,…​,3600]

low

sasl.login.refresh.min.period.seconds

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.

short

60

[0,…​,900]

low

sasl.login.refresh.window.factor

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.

double

0.8

[0.5,…​,1.0]

low

sasl.login.refresh.window.jitter

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.

double

0.05

[0.0,…​,0.25]

low

ssl.cipher.suites

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.

list

null

low

ssl.endpoint.identification.algorithm

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

string

https

low

ssl.keymanager.algorithm

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

string

SunX509

low

ssl.secure.random.implementation

The SecureRandom PRNG implementation to use for SSL cryptography operations.

string

null

low

ssl.trustmanager.algorithm

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

string

PKIX

low

transaction.timeout.ms

The maximum amount of time in ms that the transaction coordinator will wait for a transaction status update from the producer before proactively aborting the ongoing transaction.If this value is larger than the transaction.max.timeout.ms setting in the broker, the request will fail with a InvalidTransactionTimeout error.

int

60000

low

transactional.id

The TransactionalId to use for transactional delivery. This enables reliability semantics which span multiple producer sessions since it allows the client to guarantee that transactions using the same TransactionalId have been completed prior to starting any new transactions. If no TransactionalId is provided, then the producer is limited to idempotent delivery. Note that enable.idempotence must be enabled if a TransactionalId is configured. The default is null, which means transactions cannot be used. Note that transactions requires a cluster of at least three brokers by default what is the recommended setting for production; for development you can change this, by adjusting broker setting transaction.state.log.replication.factor.

string

null

non-empty string

low

bootstrap.servers

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).

list

high

ssl.key.password

The password of the private key in the key store file. This is optional for client.

password

null

high

ssl.keystore.location

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

string

null

high

ssl.keystore.password

The store password for the key store file. This is optional for client and only needed if ssl.keystore.location is configured.

password

null

high

ssl.truststore.location

The location of the trust store file.

string

null

high

ssl.truststore.password

The password for the trust store file. If a password is not set access to the truststore is still available, but integrity checking is disabled.

password

null

high

client.id

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.

string

""

medium

connections.max.idle.ms

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

long

300000

medium

receive.buffer.bytes

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.

int

65536

[-1,…​]

medium

request.timeout.ms

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.

int

120000

[0,…​]

medium

sasl.client.callback.handler.class

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

class

null

medium

sasl.jaas.config

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;

password

null

medium

sasl.kerberos.service.name

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

string

null

medium

sasl.login.callback.handler.class

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

class

null

medium

sasl.login.class

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

class

null

medium

sasl.mechanism

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

string

GSSAPI

medium

security.protocol

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

string

PLAINTEXT

medium

send.buffer.bytes

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.

int

131072

[-1,…​]

medium

ssl.enabled.protocols

The list of protocols enabled for SSL connections.

list

TLSv1.2,TLSv1.1,TLSv1

medium

ssl.keystore.type

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

string

JKS

medium

ssl.protocol

The SSL protocol used to generate the SSLContext. Default setting is TLS, which is fine for most cases. Allowed values in recent JVMs are TLS, TLSv1.1 and TLSv1.2. SSL, SSLv2 and SSLv3 may be supported in older JVMs, but their usage is discouraged due to known security vulnerabilities.

string

TLS

medium

ssl.provider

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

string

null

medium

ssl.truststore.type

The file format of the trust store file.

string

JKS

medium

metadata.max.age.ms

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.

long

300000

[0,…​]

low

metric.reporters

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.

list

""

low

metrics.num.samples

The number of samples maintained to compute metrics.

int

2

[1,…​]

low

metrics.recording.level

The highest recording level for metrics.

string

INFO

[INFO, DEBUG]

low

metrics.sample.window.ms

The window of time a metrics sample is computed over.

long

30000

[0,…​]

low

reconnect.backoff.max.ms

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.