Puppet refuses to run: “run already in progress”

Recently, one of the servers appeared to not be keeping up with configuration changes. Since it runs Puppet, this is a problem – it means that the changes at the puppet server are not getting propagated to the clients. The server is running Ubuntu Lucid Lynx Server 10.04.3 and Puppet 2.6.3.

So I shut down the puppet agent and tried running it manually:

# service puppet stop
 * Stopping puppet agent
   ...done.
# puppet agent --test
notice: Run of Puppet configuration client already in progress; skipping
#

Since puppet is definitively not running, I had to do some research and find out why it was not running.

I found this bug (Puppet bug #2888) that stated sometimes puppet does not remove its lockfile /var/lib/puppet/state/puppetdlock. Sure enough, on my system, the lockfile was still there. I deleted it and puppet ran normally.

There was also a bug report (Puppet bug #5246) that suggested puppet sometimes does not remove its pidfile /var/lib/puppet/run/agent.pid. Some of the testing suggests that this bug is confined to running puppet --onetime (without other options). I don’t think this affected me: after removing the lockfile, puppet ran normally.