8.2. 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. The OpenStack common library project, oslo, supports the following implementation of AMQP: RabbitMQ, and Qpid .
The following tables contain settings to configure the messaging middleware for the Image service:

Table 8.17. Description of AMQP configuration options

Configuration option = Default value Description
[DEFAULT]
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 = image.localhost (StrOpt) Default publisher_id for outgoing notifications.
disabled_notifications = (ListOpt) List of disabled notifications. A notification can be given either as a notification type to disable a single event, or as a notification group prefix to disable all events within a group. Example: if this config option is set to ["image.create", "metadef_namespace"], then "image.create" notification will not be sent after image is created and none of the notifications for metadefinition namespaces will be sent.
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, we fall back to the rpc_backend option and driver specific configuration.

Table 8.18. Description of RPC configuration options

Configuration option = Default value Description
[DEFAULT]
allowed_rpc_exception_modules = openstack.common.exception, glance.common.exception, exceptions (ListOpt) Modules of exceptions that are permitted to be recreated upon receiving exception data from an rpc call.
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_conn_pool_size = 30 (IntOpt) Size of RPC connection pool.
rpc_response_timeout = 60 (IntOpt) Seconds to wait for a response from a call.
[oslo_concurrency]
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.
[oslo_messaging_amqp]
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)
password = (StrOpt) Password for message broker authentication.
sasl_config_dir = (StrOpt) Path to directory that contains the SASL configuration.
sasl_config_name = (StrOpt) Name of configuration file (without .conf suffix).
sasl_mechanisms = (StrOpt) Space separated list of acceptable SASL mechanisms.
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
username = (StrOpt) User name for message broker authentication.

Table 8.19. Description of RabbitMQ configuration options

Configuration option = Default value Description
[oslo_messaging_rabbit]
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 we 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_reconnect_timeout = 60 (IntOpt) How long to wait before considering a reconnect attempt to have failed. This value should not be longer than rpc_response_timeout.
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 may be available on some distributions.
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.
send_single_repl = False (BoolOpt) Send a single AMQP reply to call message. The current behavior since oslo-incubator is to send two AMQP replies - first one with the payload, a second one to ensure the other has finished to send the payload. We are going to remove it in the N release, but we must keep backward compatible at the same time. This option provides such compatibility - it defaults to False in Liberty and can be turned on for early adopters with new installations or for testing. This option will be removed in the Mitaka release.

Table 8.20. 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.
send_single_reply = False (BoolOpt) Send a single AMQP reply to call message. The current behavior since oslo-incubator is to send two AMQP replies - first one with the payload, a second one to ensure the other has finished to send the payload. We are going to remove it in the N release, but we must keep backward compatible at the same time. This option provides such compatibility - it defaults to False in Liberty and can be turned on for early adopters with new installations or for testing. This option will be removed in the Mitaka release.