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11.3. Configure the RPC messaging system

OpenStack projects use an open standard for messaging middleware known as AMQP. This messaging middleware enables the OpenStack services that run on multiple servers to talk to each other. OpenStack Oslo RPC supports two implementations of AMQP: RabbitMQ and Qpid.

11.3.1. Configure RabbitMQ

OpenStack Oslo RPC uses RabbitMQ by default. Use these options to configure the RabbitMQ message system. The rpc_backend option is optional as long as RabbitMQ is the default messaging system. However, if it is included in the configuration, you must set it to heat.openstack.common.rpc.impl_kombu.
rpc_backend = heat.openstack.common.rpc.impl_kombu
Use these options to configure the RabbitMQ messaging system. You can configure messaging communication for different installation scenarios, tune retries for RabbitMQ, and define the size of the RPC thread pool. To monitor notifications through RabbitMQ, you must set the notification_driver option to heat.openstack.common.notifier.rpc_notifier in the heat.conf file:

Table 11.31.  Description of RabbitMQ configuration options

Configuration option = Default valueDescription
[oslo_messaging_rabbit]
amqp_auto_delete = False (Boolean) Auto-delete queues in AMQP.
amqp_durable_queues = False (Boolean) Use durable queues in AMQP.
channel_max = None (Integer) Maximum number of channels to allow
default_notification_exchange = ${control_exchange}_notification (String) Exchange name for for sending notifications
default_notification_retry_attempts = -1 (Integer) Reconnecting retry count in case of connectivity problem during sending notification, -1 means infinite retry.
default_rpc_exchange = ${control_exchange}_rpc (String) Exchange name for sending RPC messages
default_rpc_retry_attempts = -1 (Integer) Reconnecting retry count in case of connectivity problem during sending RPC message, -1 means infinite retry. If actual retry attempts in not 0 the rpc request could be processed more then one time
fake_rabbit = False (Boolean) Deprecated, use rpc_backend=kombu+memory or rpc_backend=fake
frame_max = None (Integer) The maximum byte size for an AMQP frame
heartbeat_interval = 1 (Integer) How often to send heartbeats for consumer's connections
heartbeat_rate = 2 (Integer) How often times during the heartbeat_timeout_threshold we check the heartbeat.
heartbeat_timeout_threshold = 60 (Integer) Number of seconds after which the Rabbit broker is considered down if heartbeat's keep-alive fails (0 disable the heartbeat). EXPERIMENTAL
host_connection_reconnect_delay = 0.25 (Floating point) Set delay for reconnection to some host which has connection error
kombu_compression = None (String) EXPERIMENTAL: Possible values are: gzip, bz2. If not set compression will not be used. This option may notbe available in future versions.
kombu_failover_strategy = round-robin (String) Determines how the next RabbitMQ node is chosen in case the one we are currently connected to becomes unavailable. Takes effect only if more than one RabbitMQ node is provided in config.
kombu_missing_consumer_retry_timeout = 60 (Integer) How long to wait a missing client beforce abandoning to send it its replies. This value should not be longer than rpc_response_timeout.
kombu_reconnect_delay = 1.0 (Floating point) How long to wait before reconnecting in response to an AMQP consumer cancel notification.
kombu_ssl_ca_certs = (String) SSL certification authority file (valid only if SSL enabled).
kombu_ssl_certfile = (String) SSL cert file (valid only if SSL enabled).
kombu_ssl_keyfile = (String) SSL key file (valid only if SSL enabled).
kombu_ssl_version = (String) SSL version to use (valid only if SSL enabled). Valid values are TLSv1 and SSLv23. SSLv2, SSLv3, TLSv1_1, and TLSv1_2 may be available on some distributions.
notification_listener_prefetch_count = 100 (Integer) Max number of not acknowledged message which RabbitMQ can send to notification listener.
notification_persistence = False (Boolean) Persist notification messages.
notification_retry_delay = 0.25 (Floating point) Reconnecting retry delay in case of connectivity problem during sending notification message
pool_max_overflow = 0 (Integer) Maximum number of connections to create above `pool_max_size`.
pool_max_size = 10 (Integer) Maximum number of connections to keep queued.
pool_recycle = 600 (Integer) Lifetime of a connection (since creation) in seconds or None for no recycling. Expired connections are closed on acquire.
pool_stale = 60 (Integer) Threshold at which inactive (since release) connections are considered stale in seconds or None for no staleness. Stale connections are closed on acquire.
pool_timeout = 30 (Integer) Default number of seconds to wait for a connections to available
rabbit_ha_queues = False (Boolean) Try to use HA queues in RabbitMQ (x-ha-policy: all). If you change this option, you must wipe the RabbitMQ database. In RabbitMQ 3.0, queue mirroring is no longer controlled by the x-ha-policy argument when declaring a queue. If you just want to make sure that all queues (except those with auto-generated names) are mirrored across all nodes, run: "rabbitmqctl set_policy HA '^(?!amq\.).*' '{"ha-mode": "all"}' "
rabbit_host = localhost (String) The RabbitMQ broker address where a single node is used.
rabbit_hosts = $rabbit_host:$rabbit_port (List) RabbitMQ HA cluster host:port pairs.
rabbit_interval_max = 30 (Integer) Maximum interval of RabbitMQ connection retries. Default is 30 seconds.
rabbit_login_method = AMQPLAIN (String) The RabbitMQ login method.
rabbit_max_retries = 0 (Integer) Maximum number of RabbitMQ connection retries. Default is 0 (infinite retry count).
rabbit_password = guest (String) The RabbitMQ password.
rabbit_port = 5672 (Port number) The RabbitMQ broker port where a single node is used.
rabbit_qos_prefetch_count = 0 (Integer) Specifies the number of messages to prefetch. Setting to zero allows unlimited messages.
rabbit_retry_backoff = 2 (Integer) How long to backoff for between retries when connecting to RabbitMQ.
rabbit_retry_interval = 1 (Integer) How frequently to retry connecting with RabbitMQ.
rabbit_transient_queues_ttl = 1800 (Integer) Positive integer representing duration in seconds for queue TTL (x-expires). Queues which are unused for the duration of the TTL are automatically deleted. The parameter affects only reply and fanout queues.
rabbit_use_ssl = False (Boolean) Connect over SSL for RabbitMQ.
rabbit_userid = guest (String) The RabbitMQ userid.
rabbit_virtual_host = / (String) The RabbitMQ virtual host.
rpc_listener_prefetch_count = 100 (Integer) Max number of not acknowledged message which RabbitMQ can send to rpc listener.
rpc_queue_expiration = 60 (Integer) Time to live for rpc queues without consumers in seconds.
rpc_reply_exchange = ${control_exchange}_rpc_reply (String) Exchange name for receiving RPC replies
rpc_reply_listener_prefetch_count = 100 (Integer) Max number of not acknowledged message which RabbitMQ can send to rpc reply listener.
rpc_reply_retry_attempts = -1 (Integer) Reconnecting retry count in case of connectivity problem during sending reply. -1 means infinite retry during rpc_timeout
rpc_reply_retry_delay = 0.25 (Floating point) Reconnecting retry delay in case of connectivity problem during sending reply.
rpc_retry_delay = 0.25 (Floating point) Reconnecting retry delay in case of connectivity problem during sending RPC message
socket_timeout = 0.25 (Floating point) Set socket timeout in seconds for connection's socket
ssl = None (Boolean) Enable SSL
ssl_options = None (Dict) Arguments passed to ssl.wrap_socket
tcp_user_timeout = 0.25 (Floating point) Set TCP_USER_TIMEOUT in seconds for connection's socket

11.3.2. Configure Qpid

Use these options to configure the Qpid messaging system for OpenStack Oslo RPC. Qpid is not the default messaging system, so you must enable it by setting the rpc_backend option in the heat.conf file:
rpc_backend=heat.openstack.common.rpc.impl_qpid
This critical option points the compute nodes to the Qpid broker (server). Set the qpid_hostname option to the host name where the broker runs in the heat.conf file.
Note
The qpid_hostname option accepts a host name or IP address value.
qpid_hostname = hostname.example.com
If the Qpid broker listens on a port other than the AMQP default of 5672, you must set the qpid_port option to that value:
qpid_port = 12345
If you configure the Qpid broker to require authentication, you must add a user name and password to the configuration:
qpid_username = username
qpid_password = password
By default, TCP is used as the transport. To enable SSL, set the qpid_protocol option:
qpid_protocol = ssl
Use these additional options to configure the Qpid messaging driver for OpenStack Oslo RPC. These options are used infrequently.

Table 11.32. Description of Qpid configuration options

Configuration option = Default value Description
[oslo_messaging_qpid]
amqp_auto_delete = False (BoolOpt) Auto-delete queues in AMQP.
amqp_durable_queues = False (BoolOpt) Use durable queues in AMQP.
qpid_heartbeat = 60 (IntOpt) Seconds between connection keepalive heartbeats.
qpid_hostname = localhost (StrOpt) Qpid broker hostname.
qpid_hosts = $qpid_hostname:$qpid_port (ListOpt) Qpid HA cluster host:port pairs.
qpid_password = (StrOpt) Password for Qpid connection.
qpid_port = 5672 (IntOpt) Qpid broker port.
qpid_protocol = tcp (StrOpt) Transport to use, either 'tcp' or 'ssl'.
qpid_receiver_capacity = 1 (IntOpt) The number of prefetched messages held by receiver.
qpid_sasl_mechanisms = (StrOpt) Space separated list of SASL mechanisms to use for auth.
qpid_tcp_nodelay = True (BoolOpt) Whether to disable the Nagle algorithm.
qpid_topology_version = 1 (IntOpt) The qpid topology version to use. Version 1 is what was originally used by impl_qpid. Version 2 includes some backwards-incompatible changes that allow broker federation to work. Users should update to version 2 when they are able to take everything down, as it requires a clean break.
qpid_username = (StrOpt) Username for Qpid connection.
rpc_conn_pool_size = 30 (IntOpt) Size of RPC connection pool.

11.3.3. Configure messaging

Use these common options to configure the RabbitMQ and Qpid messaging drivers:

Table 11.33.  Description of AMQP configuration options

Configuration option = Default valueDescription
[DEFAULT]
control_exchange = openstack (String) The default exchange under which topics are scoped. May be overridden by an exchange name specified in the transport_url option.
default_notification_level = INFO (String) Default notification level for outgoing notifications.
default_publisher_id = None (String) Default publisher_id for outgoing notifications.
transport_url = None (String) A URL representing the messaging driver to use and its full configuration. If not set, we fall back to the rpc_backend option and driver specific configuration.

Table 11.34.  Description of RPC configuration options

Configuration option = Default valueDescription
[DEFAULT]
engine_life_check_timeout = 2 (Integer) RPC timeout for the engine liveness check that is used for stack locking.
rpc_backend = rabbit (String) The messaging driver to use, defaults to rabbit. Other drivers include amqp and zmq.
rpc_cast_timeout = -1 (Integer) Seconds to wait before a cast expires (TTL). The default value of -1 specifies an infinite linger period. The value of 0 specifies no linger period. Pending messages shall be discarded immediately when the socket is closed. Only supported by impl_zmq.
rpc_conn_pool_size = 30 (Integer) Size of RPC connection pool.
rpc_poll_timeout = 1 (Integer) The default number of seconds that poll should wait. Poll raises timeout exception when timeout expired.
rpc_response_timeout = 60 (Integer) Seconds to wait for a response from a call.
[oslo_concurrency]
disable_process_locking = False (Boolean) Enables or disables inter-process locks.
lock_path = None (String) Directory to use for lock files. For security, the specified directory should only be writable by the user running the processes that need locking. Defaults to environment variable OSLO_LOCK_PATH. If external locks are used, a lock path must be set.
[oslo_messaging_amqp]
allow_insecure_clients = False (Boolean) Accept clients using either SSL or plain TCP
broadcast_prefix = broadcast (String) address prefix used when broadcasting to all servers
container_name = None (String) Name for the AMQP container
group_request_prefix = unicast (String) address prefix when sending to any server in group
idle_timeout = 0 (Integer) Timeout for inactive connections (in seconds)
password = (String) Password for message broker authentication
sasl_config_dir = (String) Path to directory that contains the SASL configuration
sasl_config_name = (String) Name of configuration file (without .conf suffix)
sasl_mechanisms = (String) Space separated list of acceptable SASL mechanisms
server_request_prefix = exclusive (String) address prefix used when sending to a specific server
ssl_ca_file = (String) CA certificate PEM file to verify server certificate
ssl_cert_file = (String) Identifying certificate PEM file to present to clients
ssl_key_file = (String) Private key PEM file used to sign cert_file certificate
ssl_key_password = None (String) Password for decrypting ssl_key_file (if encrypted)
trace = False (Boolean) Debug: dump AMQP frames to stdout
username = (String) User name for message broker authentication
[oslo_messaging_notifications]
driver = [] (Multi-valued) The Drivers(s) to handle sending notifications. Possible values are messaging, messagingv2, routing, log, test, noop
topics = notifications (List) AMQP topic used for OpenStack notifications.
transport_url = None (String) A URL representing the messaging driver to use for notifications. If not set, we fall back to the same configuration used for RPC.

Table 11.35.  Description of notification configuration options

Configuration option = Default valueDescription
[DEFAULT]
onready = None (String) Deprecated.