DevOps: Puppet, Docker, and Kubernetes

Using ERB templates

While you can deploy config files easily with Puppet as simple text files, templates are much more powerful. A template file can do calculations, execute Ruby code, or reference the values of variables from your Puppet manifests. Anywhere you might deploy a text file using Puppet, you can use a template instead.

In the simplest case, a template can just be a static text file. More usefully, you can insert variables into it using the ERB (embedded Ruby) syntax. For example:

  <%= @name %>, this is a very large drink.

If the template is used in a context where the variable $name contains Zaphod Beeblebrox, the template will evaluate to:

  Zaphod Beeblebrox, this is a very large drink.

This simple technique is very useful to generate ...