Green Dream disturbed my sleep to write:
You could use something like Puppet or Chef to manage multiple nodes. However, the compute resources and time involved with setting up either solution are high enough that it probably wouldn't make sense to do this for only 3 nodes.
An alternative to Puppet or Chef (and I'm a fan of both) would be Ansible; it's much simpler to pick up, and uses SSH to connect to machines to manage them -- no master server needed. I'd say that with three nodes, something like this is pretty close to being worth your time. Have a look through the walkthrough:
http://docs.ansible.com/ansible/intro_getting_started.html
Thanks, Hugh