I just recently set up puppet + mcollective + rabbitmq. Stack Exchange has other answers that compare RabbitMQ and ActiveMQ. Google offers many anecdotes that suggest RabbitMQ scales well. I preferred it because I could apt-get install Ubuntu packages from the rabbitmq site and get up and running quickly, and it seems to work fine so far.
Some suggestions:
. Install puppet and mcollective packages from puppetlabs, and configure apt preferences to Pin to their repository.
. Install rabbitmq packages from the rabbitmq apt repo, similarly Pinned.
In Ubuntu Lucid, with rabbitmq installed, you set up a configuration file:
/etc/rabbitmq/rabbitmq.config:
[
{
rabbitmq_stomp, [{tcp_listeners, [{"127.0.0.1", 6163}]},
{default_user, [{login, "guest"},{passcode, "guest"}]}
]
}
].
Then for mcollective you have /etc/mcollective/{server,client}.cfg that specify the host, port, and credentials to talk to rabbit:
... snip ...
connector = stomp
plugin.stomp.host = rabbitmq.yourdomain
plugin.stomp.port = 6163
plugin.stomp.user = guest
plugin.stomp.password = guest
Then you should be able to see them interact:
mco ping
mc-find-hosts
Mcollective doesn't come with much, you have to add plugins:
http://projects.puppetlabs.com/projects/mcollective-plugins/wiki/InstallingPlugins
including one for interacting with puppet, services, processes, etc.