I have clients connecting to a puppetmaster and I'm running the puppet agent commands though mcollective. Just today (and to my knowledge we haven't changed anything) all mco puppet commands are resulting in no changes being applied. The machines run the puppet agent, I can see in the logs that the catalog run finishes, it just doesn't do anything. However if I ssh onto the agent boxes and run puppet it applies the appropriate changes.
I checked exactly what command mcollective is telling puppet to run and it's puppet agent --test --color=false --splay --splaylimit 30. So I made sure that's what I'm running on the boxes too.
Update: I just noticed that over the last couple of days we are starting to get some Could not retrieve catalog from remote server: wrong header line format errors when puppet is run from mcollective. Again, this never happens when I run it manually at the command line.
These are Ubuntu boxes (12.10), running puppet 3.4.2 on the agents and 3.3.0 on the puppetmaster with mcollective 2.4.0.
So it turns out puppet was just passing on the error from hiera. We were using the hiera_http backend & it was it that was getting the
wrong header line formaterror. Seems our JSON was a bit to slow to download. Fixed it by getting jenkins to download the JSON first into the hiera data folder, then run puppet.