Puppet Configuration Checks with Jenkins

Ok, so we have all our Nagios configs being sanitized and checked by Jenkins, why not Puppet: IT Automation Software for System Administrators? WHY NOT PUPPET!?

A lot of this is going to be rehash of the PRIOR article but I wanted to document this out for later anyways since it’s slightly different.

Step One: Assumptions and Layout

I’m going to stop and assume we are well past the Jenkins setup phase. Please see the prior article for that… or better yet? make puppet do it for you. That’s what it is for.

Now Puppet is a system that hold dynamically updated configurations of your everything and Jenkins is a system that automatically runs random code summated to it to validate it. I think needless to say I’m not even going to consider these two pieces of software running on the same machine. I’m serious the answer is NO.

Ok, now lets start by assuming the following;

  1. You are not using anything crazy like githubbing puppet configs nor can you afford github enterprise.
  2. Puppet Master (puppet.domain.ex) runs in DMZ and is locked down tight.
  3. /etc/puppet is your config locations on puppet.domain.ex and you have a user that can write to it other than root.
  4. Jenkins is hidden away in your network where it belongs, also fairly secured.
  5. Your central git server is on the same lan as your Jenkins, if not on the same box for some reason.
  6. You solemly swear not to do anything stupid and copy paste anything from this document directly into a command prompt. I may toss a bad char in there just to keep you honest.

We have a few caveats to overcome here but it’s not impossible.

Step Two: Prepare your Puppet box

Puppet server should be locked down. So for my it’s a box with all the screws down tight as they can be, puppet’s web port and ssh passworded key to one user only is enabled. In order to allow pushing changes through git we will set up our friend the hub repo.

# Make puppet config directory a git repo
cd /etc/puppet
git init
git add .
git commit -m"Inital Commit"
# Make a hub repo in home
cd ~
mkdir puppet_configs.git
git --bare init
# Link and push to our hub
cd /etc/puppet
git remote add hub ~/puppet_configs.git
git push hub master

There! That wasn’t hard at all. In fact it was a short rehash of what I did last yesterday. However, lets add the post-merge hook to THIS hub.

cat __EOF__
cd /etc/puppet
unset GIT_DIR
/usr/bin/git pull hub master
__EOF__ >  ~/puppet_configs.git/hooks/post-merge
chmod 755  ~/puppet_configs.git/hooks/post-merge

So now when the hub gets pushed to, puppet gets a fresh load of configs and it does whatever it needs to do from then on out! Yea? Awesome

Now get out of your puppet box and STAY OUT (until it breaks, you did set up Nagios on it right?)

Step Three: Jenkins

In case you haven’t already Jenkins is going to need a few upgrades. Hit it up with the following plugins.

I have been told you can set up this to work with the RVM plugin to deploy this and that but I took the cheap route since puppet is installed on this machine anyways. For this setup we will need one gem though. If this is for a buisness network I’d go the extra hours to learn RVM but it’s not, this is my home lab.

Now this is where I start to steal heavily from Continuous Deployment with Jenkins and Puppet.

Now starts the puppet configurations!

On your git repo for puppet you need to add a ‘post-update’ hook. to trigger builds remotely. Don’t forget to sub out YOUR_TOKEN with the token you picked above and set the kenkins server proper. The quick and dirty is;

cd puppet_configs.git/hooks
cat __EOL__
echo "Sending build command to Jenkins"
curl -sSL 'http://mycooljenkins:8080/job/Nagios_Config/build?token=YOUR_TOKEN' >> /dev/null
exec git update-server-info
__EOL__ >> post-update
chmod 755 post-update

Now lets add two execute shell actions.

Build Execute Shell Number one:

for file in $(find . -iname '*.pp’)
  puppet parser validate \
    --render-as s \
    --modulepath=modules \
    "$file" || exit 1;

Build Execute Shell Number two:

find . -iname *.pp -exec puppet-lint --log-format "%{path}:%{linenumber}:%{check}:%{KIND}:%{message}" {}  \;

The second one shouldn’t error out but it will toss up style warnings and possible errors so lets check for those with our warning plugin.

Step four: The Danger Zone

Now this is where you might expect me to tell you to set up a Post-Build Action using Git Publisher or some script or another to automate your verified go-live puppet, maybe with a cool mcollector call to speed up your push…

That recommendation is NOT forthcoming

The simple fact of the matter is that if you are automatically pushing configs to puppet from Jenkins you have;

  1. A passwordless key laying around on a CI box (and any boxes Jenkins spawns) to your puppet config (or worse)
  2. Much much bigger balls than me
  3. Hopefully a whole enterprise security team all over this shit like a hawk.

You can set up an automated push and hope that everything you or anyone else pushes in master is gold but my recommendation is to test in branches, tag, and then have a human eyes verification on the configs before your push to puppet. When you have a bad push to nagios monitoring glitches out. When pupped fucks up… well you are running down a bad road at full speed.

  1. Seriously, if you don’t have a central git server set up a central git repo SOMEWHERE safe, even on your jenkins box if need be (like we did for nagios) Just remember that your going to end up with something sensitive in there someday. ↩︎

  2. You still want to regularly poll the git repo regularly just in case a commit script fails, it’s no good to have it falling through the cracks. ↩︎

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