Pull facts about a node, and then preview Hiera changes there, without touching the node.

This is intended for Puppet 3.x and below. In Puppet 4, the puppet lookup command accomplishes the same thing. If you have Puppet 4, you should be using this built-in tool, and I will too once my Puppet installation gets to version 4.

Hiera is a critical part of a Puppet implementation, and it is amazingly helpful to separate data from code.

The Hiera Simulator simplifies the development process by allowing someone to "preview" Hiera changes without committing to source control, awaiting results from CI tests, or touching any real hosts in the environment. While it's possible to do all this with stock Hiera, that involves copying facts and using less common command line options. Hiera Simulator handles all that for you, and then calls the actual Hiera code to do your lookup.

This code is meant to run on a developer's workstation -- perhaps in some cases it's also suitable for your Puppet Master, but it's definitely not intended to be installed everywhere in your environment. Once you've installed the code, you'll have to do a bit of configuration so it knows where to find everything.

• Installation
• Configuration

Because the version of Hiera to use is set in the Gemfile, you may have to update the Gemfile to match your version. This code is intended to work correctly with both Hiera 1.3.4 and Hiera 3.1. No default version of the Hiera gem is required in the default Gemfile, so if you run Puppet from gems (like we do at my work), it won't conflict.

Type hiera-simulator --help for a list of command line options.

Here are the important ones:

• -n FQDN: The FQDN of the host whose facts you want to use. This option is required unless you use --fact-file FILENAME to provide the facts for you.

• -d: Turn on Hiera debug mode, which will show you what files were tried until it ultimately came up with your fact.

• --fact-file FILENAME: Instead of providing a node name and letting Hiera Simulator find the facts for you, load the facts directly from the file you specify. The fact file may be in YAML or JSON format (parsing method depends on file extension).

• Troubleshooting

• Limitations