Parallelising rspec-puppet

I recently migrated a client away from Andrew Cunningham’s puppet-validator – an open source project that simply compiles catalogs based on configurable fact values – to rspec-puppet.

The advantages of rspec-puppet are many and, obviously, being able to do more than just compile catalogs is one advantage.  However, Andrew’s project also had some advantages; in particular it used threads to parallelise catalog compilation.  This meant that some 100 catalogs could be compiled and tested on my 8 CPU-core laptop in less than 3 minutes.  After setting up rspec-puppet, however, I found that the same tests were now taking over 20 minutes.

It seems to me that the Puppet community has thus far tolerated rspec-puppet’s slowness.  To illustrate, I’ll focus in this post on the very mature Puppet Labs Apache module and show how parallelising its rspec-puppet tests by setting up Michael Grosser’s parallel_tests would get the current execution time of about 30 minutes (on my laptop) down to under three.

Running the rspec tests in puppetlabs/apache

To get started, let’s clone the puppetlabs/apache module:

$ cd /tmp $ git clone read more

Using catalog-diff while refactoring Puppet code

In yesterday’s post I showed how you can compile a Puppet catalog from a bundle on a laptop.  Today I’m going to show how you can use Zack Smith’s catalog diff tool to assist with complex refactoring changes.

Code examples

For the purpose of describing how to use the catalog diff tool, it will be better to use an artificially simple code example.  Imagine we have all of our code in site.pp as follows:

node '' { file { '/tmp/myfile': ensure => file, content => "My hostname is ${::hostname}\n", } } read more

Compiling a puppet catalog – on a laptop

From time to time I have wished that I could easily compile a Puppet catalog from my laptop. Use cases that spring to mind include, "hey, wouldn't it be great if I could see what this super-complicated Puppet Forge module is actually doing without having to spin up a VM and 'puppet apply' it". Othertimes it has just been curiosity.