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 three implementations of AMQP: RabbitMQ, Qpid, and ZeroMQ.

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 nova.openstack.common.rpc.impl_kombu. rpc_backend=nova.openstack.common.rpc.impl_kombu 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.notifier.rabbit_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.

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. rpc_backend=nova.openstack.common.rpc.impl_qpid 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 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 This table lists additional options that you use to configure the Qpid messaging driver for OpenStack Oslo RPC. These options are used infrequently.

Use these options to configure the ZeroMQ messaging system for OpenStack Oslo RPC. ZeroMQ is not the default messaging system, so you must enable it by setting the rpc_backend option in the nova.conf file.

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