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Use the coordination module to manage restarting the rabbitmq services. This is to ensure that restarts are only performed on one unit at a time. This helps prevent situation which can cause the cluster to become split brained (eg if two or more nodes are restarted at the same time). * Manually run _run_atstart & _run_atexit method when actions are run as this does not happen automatically and is needed by the coordination layer. * Replace restart_on_change decorator with coordinated_restart_on_change. coordinated_restart_on_change includes logic for requesting restart locks from the coordination module. * The coordination module works via the leader and cluster events so the hooks now include calls to check_coordinated_functions which will run any function that is waiting for a lock. * Logic has been added to check for the situation where a hook is being run via the run_deferred_hooks actions. If this is the case then restarts are immediate as the action should only be run on one unit at a time. Change-Id: Ia133c90a610793d4da96d3400a3906b801b52b73 |
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README.md
Overview
RabbitMQ is an implementation of AMQP, the emerging standard for high performance enterprise messaging. The RabbitMQ server is a robust and scalable implementation of an AMQP broker.
The rabbitmq-server charm deploys RabbitMQ server and provides AMQP services to those charms that support the rabbitmq interface. The current list of such charms can be obtained from the Charm Store (the charms officially supported by the OpenStack Charms project are published by 'openstack-charmers').
Usage
Configuration
This section covers common and/or important configuration options. See file
config.yaml for the full list of options, along with their descriptions and
default values. See the Juju documentation for details
on configuring applications.
min-cluster-size
The min-cluster-size option sets the number of rabbitmq-server units required
to form its cluster. It is best practice to use this option as doing so ensures
that the charm will wait until the cluster is up before accepting relations
from other client applications.
source
The source option sets an alternate software source and can be passed during
or after deployment. The default behaviour is to use the Ubuntu package archive
for the underlying machine series. The most common value is a UCA cloud
pocket (e.g. 'cloud:bionic-train'). In the case of a non-OpenStack project,
there is no guarantee that a candidate will be found in the stated UCA pocket.
Note: Changing the value of this option post-deployment will trigger a software upgrade. See OpenStack upgrade in the OpenStack Charms Deployment Guide.
Deployment
To deploy a single rabbitmq-server unit:
juju deploy rabbitmq-server
To make use of AMQP services, simply add a relation between rabbitmq-server and an application that supports the rabbitmq interface. For instance:
juju add-relation rabbitmq-server:amqp nova-cloud-controller:amqp
Monitoring
To collect RabbitMQ metrics, add a relation between rabbitmq-server and
an application that supports the scrape interface. For instance:
juju add-relation rabbitmq-server:scrape prometheus:scrape
Note: The scrape relation is only supported when the RabbitMQ version is >= 3.8.
The charm can be related to a dashboard charm like grafana to view visualization metrics:
juju add-relation rabbitmq-server:dashboards grafana:dashboards
To get alerts of RabbitMQ split-brain events, add a relation between rabbitmq-server and
an application that supports the prometheus-rules interface. For instance:
juju add-relation rabbitmq-server:prometheus-rules prometheus:prometheus-rules
High availability
When more than one unit is deployed the charm will bring up a native RabbitMQ
HA active/active cluster. The min-cluster-size option should be used (see
description above).
See Infrastructure high availability in the OpenStack Charms Deployment Guide for details.
TLS
Communication between the AMQP message queue and client services (OpenStack applications) can be TLS-encrypted. There are two methods for managing keys and certificates:
- with Vault
- manually (via charm options)
Vault can set up private keys and server certificates for an application. It also stores a central CA certificate for the cloud. See the vault charm for more information.
Vault is the recommended method and is what will be covered here.
The private key and server certificate (and its signing) are managed via a relation made to the vault application:
juju add-relation rabbitmq-server:certificates vault:certificates
Actions
This section lists Juju actions supported by the charm. Actions allow specific operations to be performed on a per-unit basis.
check-queuescluster-statuscomplete-cluster-series-upgradelist-unconsumed-queuespauseresume
To display action descriptions run juju actions --schema rabbitmq-server. If
the charm is not deployed then see file actions.yaml.
Documentation
The OpenStack Charms project maintains two documentation guides:
- OpenStack Charm Guide: for project information, including development and support notes
- OpenStack Charms Deployment Guide: for charm usage information
Bugs
For general charm questions refer to the OpenStack Charm Guide.