How to deploy and configure a multi-node RabbitMQ cluster on Ubuntu Server

Reliable, fast messaging is integral to all complex application stacks. RabbitMQ is an implementation of the AMQP protocol that offers both.

This tutorial takes you through the process of installing RabbitMQ in a high-availability RabbitMQ cluster on Ubuntu Server using Juju.

Traditionally, the initial install process has felt brittle and difficult. By the end of this tutorial, it shouldn’t feel like that anymore.

Juju software

This tutorial assumes that you have installed Juju and registered your security credentials.

Running controller

Duration 5:00

You should have access to a live Juju controller. This can be achieved in 2 ways:

1. Run juju login jaas to make use of the Canonical-hosted controller. This service is offered at no cost, but credentials are provided to Canonical.
2. Run juju bootstrap. This option may incur hosting costs, but the controller runs fully in your control.

The Juju “model” is a workspace for inter-related applications. It houses machines, containers, applications, and other components such as firewall rules.

To add a model to the controller, run the juju add-model command followed by the model name. You may name your model anything you want. Below we call it “messaging”.

$ juju add-model messaging

The juju deploy command deploys charms. A charm is managed software, that is, software enriched with all the operational know-how for it to function well in the cloud. The rabbitmq-server charm is managed RabbitMQ.

$ juju deploy rabbitmq-server -n3 --config min-cluster-size=3 rabbitmq

Juju provides the ability to interact with our cluster without knowing the host IP addresses beforehand. One of the units of the rabbitiq-server charm that’s been deployed is designated as the “leader”.

The juju exec --unit <application>/leader syntax enables commands to be executed on the host itself. The connection information is resolved by Juju.

Remove the guest user account

RabbitMQ comes with a default user account with the username guest and the password guest. In production environments, this account should be removed. This can be done via the rabbitmqctl delete_user command.

$ juju exec --unit rabbitmq/leader 'rabbitmqctl delete_user guest'

Add other user accounts

To add a new user account to RabbitMQ, use the rabbitmqctl add_user command. Below we use it to add a user account called demo.

$ export RABBIT_PASSWORD=$(head -c20 /dev/urandom | hex)
$ juju exec --unit rabbitmq/leader "rabbitmqctl add_user demo $RABBIT_PASSWORD"

To add any user tags, provide them to the rabbitmqctl set_user_tags command:

$ juju exec --unit rabbitmq/leader "rabbitmqctl set_user_tags demo administrator"

Virtual hosts (vhosts) are the primary mechanism through which access control is enforced with RabbitMQ. To create a virtual host, simply use the rabbitmqctl add_vhost command. Below we use it to create a virtual host called “vh1”.

$ juju run --unit rabbitmq/leader "rabbitmqctl add_vhost vh1"

Users are provided with permissions to specific vhosts via the rabbitmqctl set_permissions command:

$ juju run --unit rabbitmq/leader "rabbitmqctl set_permissions -p 'vh1' 'demo' '.*' '.*' '.*'"

An AMQP exchange is a message routing construct, created in RabbitMQ with the rabbitmqadmin command. You can use Juju to access this:

$ juju run --unit rabbitmq/leader "rabbitmqadmin --vhost=vh1 declare exchange name=hub type=fanout -u demo -p $RABBIT_PASSWORD" 

The RabbitMQ management plugin enables a monitoring dashboard.

Enable the dashboard

The rabbitmq-plugins command can enable the management plugin for your cluster.

$ juju run --unit rabbitmq/leader "rabbitmq-plugins enable rabbitmq_management" 

Access the dashboard from the Internet

To access the management dashboard from the Internet, ask Juju to open the firewall:

$ juju exec --unit rabbitmq/0 'open-port 15672'
$ juju expose rabbitmq