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3.6. Configure the Oslo RPC messaging system

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

3.6.1. Configure RabbitMQ

OpenStack Oslo RPC uses RabbitMQ by default. Use these options to configure the RabbitMQ message system. The rpc_backend option is not required as long as RabbitMQ is the default messaging system. However, if it is included the configuration, you must set it to rabbit.
You can use these additional 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 nova.openstack.common.notifier.rpc_notifier in the nova.conf file. The default for sending usage data is sixty seconds plus a random number of seconds from zero to sixty.

Table 3.1. Description of RabbitMQ configuration options

Configuration option = Default value Description
amqp_auto_delete = False (BoolOpt) Auto-delete queues in AMQP.
amqp_durable_queues = False (BoolOpt) Use durable queues in AMQP.
fake_rabbit = False (BoolOpt) Deprecated, use rpc_backend=kombu+memory or rpc_backend=fake
heartbeat_rate = 2 (IntOpt) How often times during the heartbeat_timeout_threshold to check the heartbeat.
heartbeat_timeout_threshold = 0 (IntOpt) Number of seconds after which the Rabbit broker is considered down if heartbeat's keep-alive fails (0 disables the heartbeat, >0 enables it. Enabling heartbeats requires kombu>=3.0.7 and amqp>=1.4.0). EXPERIMENTAL
kombu_reconnect_delay = 1.0 (FloatOpt) How long to wait before reconnecting in response to an AMQP consumer cancel notification.
kombu_ssl_ca_certs = (StrOpt) SSL certification authority file (valid only if SSL enabled).
kombu_ssl_certfile = (StrOpt) SSL cert file (valid only if SSL enabled).
kombu_ssl_keyfile = (StrOpt) SSL key file (valid only if SSL enabled).
kombu_ssl_version = (StrOpt) SSL version to use (valid only if SSL enabled). Valid values are TLSv1 and SSLv23. SSLv2, SSLv3, TLSv1_1, and TLSv1_2 are also available.
rabbit_ha_queues = False (BoolOpt) Use HA queues in RabbitMQ (x-ha-policy: all). If you change this option, you must wipe the RabbitMQ database.
rabbit_host = localhost (StrOpt) The RabbitMQ broker address where a single node is used.
rabbit_hosts = $rabbit_host:$rabbit_port (ListOpt) RabbitMQ HA cluster host:port pairs.
rabbit_login_method = AMQPLAIN (StrOpt) The RabbitMQ login method.
rabbit_max_retries = 0 (IntOpt) Maximum number of RabbitMQ connection retries. Default is 0 (infinite retry count).
rabbit_password = guest (StrOpt) The RabbitMQ password.
rabbit_port = 5672 (IntOpt) The RabbitMQ broker port where a single node is used.
rabbit_retry_backoff = 2 (IntOpt) How long to backoff for between retries when connecting to RabbitMQ.
rabbit_retry_interval = 1 (IntOpt) How frequently to retry connecting with RabbitMQ.
rabbit_use_ssl = False (BoolOpt) Connect over SSL for RabbitMQ.
rabbit_userid = guest (StrOpt) The RabbitMQ userid.
rabbit_virtual_host = / (StrOpt) The RabbitMQ virtual host.
rpc_conn_pool_size = 30 (IntOpt) Size of RPC connection pool.

3.6.2. 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 nova.conf file.
This critical option points the compute nodes to the Qpid broker (server). Set qpid_hostname to the host name where the broker runs in the nova.conf file.
The --qpid_hostname parameter accepts a host name or IP address value.
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:
If you configure the Qpid broker to require authentication, you must add a user name and password to the configuration:
By default, TCP is used as the transport. To enable SSL, set the qpid_protocol option:
This table lists additional options that you use to configure the Qpid messaging driver for OpenStack Oslo RPC. These options are used infrequently.

Table 3.2. Description of Qpid configuration options

Configuration option = Default value Description
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.

3.6.3. Configure messaging

Use these options to configure the RabbitMQ and Qpid messaging drivers.

Table 3.3. Description of AMQP configuration options

Configuration option = Default value Description
control_exchange = openstack (StrOpt) The default exchange under which topics are scoped. May be overridden by an exchange name specified in the transport_url option.
default_publisher_id = None (StrOpt) Default publisher_id for outgoing notifications
notification_driver = [] (MultiStrOpt) Driver or drivers to handle sending notifications.
notification_topics = notifications (ListOpt) AMQP topic used for OpenStack notifications.
transport_url = None (StrOpt) A URL representing the messaging driver to use and its full configuration. If not set, fall back to the rpc_backend option and driver specific configuration.

Table 3.4. Description of RPC configuration options

Configuration option = Default value Description
matchmaker_heartbeat_freq = 300 (IntOpt) Heartbeat frequency.
matchmaker_heartbeat_ttl = 600 (IntOpt) Heartbeat time-to-live.
rpc_backend = rabbit (StrOpt) The messaging driver to use, defaults to rabbit. Other drivers include qpid and zmq.
rpc_cast_timeout = 30 (IntOpt) Seconds to wait before a cast expires (TTL). Only supported by impl_zmq.
rpc_response_timeout = 60 (IntOpt) Seconds to wait for a response from a call.
rpc_thread_pool_size = 64 (IntOpt) Size of RPC thread pool.
rpc_driver_queue_base = cells.intercell (StrOpt) Base queue name to use when communicating between cells. Various topics by message type will be appended to this.
disable_process_locking = False (BoolOpt) Enables or disables inter-process locks.
lock_path = None (StrOpt) 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.
allow_insecure_clients = False (BoolOpt) Accept clients using either SSL or plain TCP
broadcast_prefix = broadcast (StrOpt) address prefix used when broadcasting to all servers
container_name = None (StrOpt) Name for the AMQP container
group_request_prefix = unicast (StrOpt) address prefix when sending to any server in group
idle_timeout = 0 (IntOpt) Timeout for inactive connections (in seconds)
server_request_prefix = exclusive (StrOpt) address prefix used when sending to a specific server
ssl_ca_file = (StrOpt) CA certificate PEM file for verifing server certificate
ssl_cert_file = (StrOpt) Identifying certificate PEM file to present to clients
ssl_key_file = (StrOpt) Private key PEM file used to sign cert_file certificate
ssl_key_password = None (StrOpt) Password for decrypting ssl_key_file (if encrypted)
trace = False (BoolOpt) Debug: dump AMQP frames to stdout
baseapi = None (StrOpt) Set a version cap for messages sent to the base api in any service