# Rabbitmq

RabbitMQ is a messaging broker, an intermediary for messaging. It gives your applications a common platform to send and receive messages, and your messages a safe place to live until received.

## Installation

Install the rabbitmq package.

## Configuration

No configuration should be needed. Simply start the `rabbitmq` service.

Default configuration file location `/etc/rabbitmq/rabbitmq-env.conf`. See more about configuration on the official docs

## Troubleshooting

### Changed hostname

If you have changed your hostname after you installed rabbitmq, it will no longer be able to start. This is due to the `NODENAME` specified in `/etc/rabbitmq/rabbitmq-env.conf`. Update it to reflect your new hostname, for example:

    /etc/rabbitmq/rabbitmq-env.conf

    NODENAME=rabbit@my-new-hostname
    ...

### Upgraded RabbitMQ to latest version and cannot start

This might cause your `/etc/rabbitmq/rabbitmq-env.conf` to get the wrong `NODENAME`. For example, it might cause it to add another `@hostname` part. In any case, this can be fixed by following #Changed hostname.

### Erlang cookie error

Failure to authenticate might be caused by a wrong rabbitmq HOME setting:

    Authentication failed (rejected by the remote node), please check the Erlang cookie
    ...
    home dir: /root

Home can be set in the configuration file:

    /etc/rabbitmq/rabbitmq-env.conf

    ...
    HOME=/var/lib/rabbitmq
    ...

Category:

- Networking