Testing Puppet code

It has been clear for years that there is the strong need to be able to test how changes to our Puppet code can affect our infrastructure.

The topic is quite large, complex, and, to be honest, not completely solved, but there are tools and methods than can help us in safely working with Puppet in a production environment.

We can test our code with these tools:

• The command puppet parser validate, to check the syntax of our manifests

• puppet-lint (http://puppet-lint.com/) to check that the style of our code conforms with the recommended style guide

• rspec-puppet to test the catalog and the logic of our modules

• rspec-puppet-system and Beaker, to test what happens when our catalog is applied to a real system

We can also follow some procedures and techniques, such as:

• Using the --noop option to verify what would be the changes before applying them

• Using Puppet environments to try our code on test systems before pushing it into production

• Having canary nodes where Puppet is run and...