I've been playing with Ansible and recently had it installing Mosquitto.

It's a bit too trivial at the moment to turn into a fully fledged Ansible roll so I've just put a Gist here.

https://gist.github.com/justinatomatic/c2cf67a6c49bcdc8702e

It's only three tasks

# install mqtt broker
  - name: add mosquitto key
    apt_key: url=http://repo.mosquitto.org/debian/mosquitto-repo.gpg.key state=present
  - name: add mosquitto repo
    apt_repository: repo='deb http://repo.mosquitto.org/debian wheezy main' state=present update_cache=yes
  - name: install mosquitto
    apt: name=mosquitto state=present