Module cheat sheet

A quick reference to Puppet module terms and concepts.

For detailed explanations of Puppet modules, see the related topics about modules.

Related topics:

• Module fundamentals: How to use and write Puppet modules.
• Installing modules: How to install pre-built modules from the Puppet Forge.
• Publishing modules: How to publish your modules to the Puppet Forge.
• Using plug-ins: How to arrange plug-ins (like custom facts and custom resource types) in modules and sync them to agent nodes.
• Documenting modules: A module README template and information on providing directions for your module.

Example Module: /etc/puppetlabs/puppet/modules/apache

manifests

This directory holds the module’s Puppet code.

• Each .pp file should contain one and only one class or defined type.
• Filenames and class/defined type names are related; see the examples below.
• Within a module, the special $module_name variable always contains the module’s name.

apache/manifests/init.pp

class apache {
...
}

init.pp is special; it should contain a class (or defined type) with the same name as the module.

apache/manifests/vhost.pp

define apache::vhost 
($port, $docroot) 
{
...
}

Other classes (and defined types) should be named modulename::filename (without the .pp extension).

apache/manifests/config/ssl.pp

class apache::config::ssl {
...
}

Subdirectories add intermediate namespaces.

files

Nodes can download any files in this directory from Puppet’s built-in file server.

• Use the source attribute to download file contents from the server.
• Use puppet:/// URIs to specify which file to fetch.
• Files in this directory are served at puppet:///modules/modulename/ filename.

apache/files/httpd.conf

To fetch this file:

file {'/etc/apache2/httpd.conf':
  ensure => file,
  source => 'puppet:///modules/apache/httpd.conf',
}

apache/files/extra/ssl

Puppet’s file server can navigate any subdirectories:

file {'/etc/apache2/httpd-ssl.conf':
  ensure => file,
  source => 'puppet:///modules/apache/extra/ssl',
}

lib

This directory holds Ruby plugins, which can add features to Puppet and Facter.

Capache/lib/puppet/type/apache_setting.rb** A custom type.

apache/lib/puppet/parser/functions/htpasswd.rb A custom function.

apache/lib/facter/apache_confdir.rb** A custom fact.

templates

This directory holds ERB templates.

• Use the template function to create a string by rendering a template.
• Use the content attribute to fill file contents with a string.
• Template files are referenced as modulename/filename.erb.

apache/templates/vhost.erb

To use this template:

file     {'/etc/apache2/sites-enabled/wordpress.conf':
  ensure => file,
  content => template('apache/vhost.erb'),
}