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RabbitMQ Cluster on a Single Machine

Rabbit MQ

If you are having problems setting up a cluster on a single machine then the following post might help answer some questions.

I assume that you have already set up RabbitMQ on your local machine (rabbit@localhost) and want to know how to add two more nodes and cluster them.

These instructions relate to the installation on a MacBook Pro running OS X Yosemite.

As you already have an installation of RabbitMQ all you need to do is instantiate instances on new nodes. The following command will instantiate an instance of Rabbit on a node called hare@localhost.

RABBITMQ_NODE_PORT=5674
RABBITMQ_NODENAME=hare@localhost
rabbitmq-server

Ensure the port number is different to the port currently in use.

A sticking point is the ports bound by Rabbit to plug-ins. You might see the following error:

BOOT FAILED
===========

Error description:
{could_not_start,rabbitmq_mqtt,
{{shutdown,
{failed_to_start_child,'rabbit_mqtt_listener_sup_:::1883',
{shutdown,
{failed_to_start_child,tcp_listener,
{cannot_listen,{0,0,0,0,0,0,0,0},1883,eaddrinuse}}}}},
{rabbit_mqtt,start,[normal,[]]}}}

This means that the Rabbit MQTT for the currently running node is using port 1883.

BOOT FAILED
===========

Error description:
{could_not_start,rabbitmq_stomp,
{{shutdown,
{failed_to_start_child,'rabbit_stomp_listener_sup_:::61613',
{shutdown,
{failed_to_start_child,tcp_listener,
{cannot_listen,{0,0,0,0,0,0,0,0},61613,eaddrinuse}}}}},
{rabbit_stomp,start,[normal,[]]}}}

This means that the Rabbit STOMP for the currently running node is using port 61613.

To resolve this conflict add an argument to RABBITMQ_SERVER_START_ARGS specifying a new port for the plug-in.

A list of installed plug-in is shown in the RabbitMQ web interface in the overview tab under ports and contexts.

The following shows how to configure ports for the Rabbit management and Rabbit MQTT

RABBITMQ_NODE_PORT=5674
RABBITMQ_NODENAME=hare@localhost
RABBITMQ_SERVER_START_ARGS="
-rabbitmq_management listener [{port,15674}]
-rabbitmq_mqtt tcp_listeners [1884]"
rabbitmq-server

Now add the node to the cluster. Stop the instance, join it to another node and start.

rabbitmqctl -n hare@localhost stop_app

rabbitmqctl -n hare@localhost join_cluster rabbit@localhost

rabbitmqctl -n hare@localhost start_app

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