Adam Bloom from Pivotal has written a guide to installing and using RabbitMQ on a cluster of Raspberry Pis.

Here’s what they say about RabbitMQ:

With Pivotal RabbitMQ, we have a highly scalable, efficient, easy-to-deploy message queue. Beyond the long list of support for languages and protocols that could connect to a cluster of Pis running RabbitMQ or distribute messages to individual Pi subscribers, RabbitMQ also supports MQTT for when Pis are clients or sensors. With MQTT, any device on a network can send data directly to a message queue, and the protocol is ideally suited for sensors and mobile devices.

Read the guide here