Configuring Messaging RPC and Notifications

TripleO can configure oslo.messaging RPC and Notification services and deploy the corresponding messaging backends for the undercloud and overcloud. The roles OsloMessagingRPC and OsloMessagingNotify have been added in place of the RabbitMQ Server. Having independent roles for RPC and Notify allows for the separation of messaging backends as well as the deployment of different messaging backend intermediaries that are supported by oslo.messaging drivers:

+----------------+-----------+-----------+-----+--------+-----------+
| Oslo.Messaging | Transport |  Backend  | RPC | Notify | Messaging |
|     Driver     | Protocol  |  Server   |     |        |   Type    |
+================+===========+===========+=====+========+===========+
|     rabbit     | AMQP V0.9 | rabbitmq  | yes |   yes  |   queue   |
+----------------+-----------+-----------+-----+--------+-----------+
|      amqp      | AMQP V1.0 | qdrouterd | yes |        |   direct  |
+----------------+-----------+-----------+-----+--------+-----------+
|     kafka      |   kafka   |  kafka    |     |   yes  |   queue   |
| (experimental) |   binary  |           |     |        |  (stream) |
+----------------+-----------+-----------+-----+--------+-----------+

Standard Deployment of RabbitMQ Server Backend

A single RabbitMQ backend (e.g. server or cluster) is the default deployment for TripleO. This messaging backend provides the services for both RPC and Notification communications through its integration with the oslo.messaging rabbit driver.

The example standard messaging environment file depicts the resource association for this defacto deployment configuration:

# *******************************************************************
# This file was created automatically by the sample environment
# generator. Developers should use `tox -e genconfig` to update it.
# Users are recommended to make changes to a copy of the file instead
# of the original, if any customizations are needed.
# *******************************************************************
# title: Share single rabbitmq backend for rpc and notify messaging backend
# description: |
#   Include this environment to enable a shared rabbitmq backend for
#   oslo.messaging rpc and notification services
  parameter_defaults:
  # The network port for messaging backend
  # Type: number
  RpcPort: 5672

resource_registry:
  OS::TripleO::Services::OsloMessagingNotify: ../../docker/services/messaging/notify-rabbitmq-shared.yaml
  OS::TripleO::Services::OsloMessagingRpc: ../../docker/services/messaging/rpc-rabbitmq.yaml

The rpc-rabbitmq.yaml instantiates the rabbitmq server backend while notify-rabbitmq-shared.yaml sets up the notification transport configuration to use the same shared rabbitmq server.

Deployment of Separate RPC and Notify Messaging Backends

Separate messaging backends can be deployed for RPC and Notification communications. For this TripleO deployment, the apache dispatch router (qdrouterd) can be deployed for the RPC messaging backend using the oslo.messaging AMQP 1.0 driver.

The example hybrid messaging environment file can be used for an overcloud deployment:

# *******************************************************************
# This file was created automatically by the sample environment
# generator. Developers should use `tox -e genconfig` to update it.
# Users are recommended to make changes to a copy of the file instead
# of the original, if any customizations are needed.
# *******************************************************************
# title: Hybrid qdrouterd for rpc and rabbitmq for notify messaging backend
# description: |
#   Include this environment to enable hybrid messaging backends for
#   oslo.messaging rpc and notification services
parameter_defaults:
  # The network port for messaging Notify backend
  # Type: number
  NotifyPort: 5672

  # The network port for messaging backend
  # Type: number
  RpcPort: 31459

resource_registry:
  OS::TripleO::Services::OsloMessagingNotify: ../../docker/services/messaging/notify-rabbitmq.yaml
  OS::TripleO::Services::OsloMessagingRpc: ../../docker/services/messaging/rpc-qdrouterd.yaml

The above will instantiate qdrouterd server(s) and configure them for use as the RPC transport and will also instantiate the rabbitmq backend and configure it for use as the Notification transport. It should be noted that the RPC and Notify ports must be distinct to prevent the qdrouterd and rabbitmq servers from simultaneously using the amqp standard port (5672).

Add the following arguments to your openstack overcloud deploy command to deploy with separate messaging backends:

openstack overcloud deploy --templates -e /usr/share/openstack-tripleo-heat-templates/environments/messaging/rpc-qdrouterd-notify-rabbitmq-hybrid.yaml