Plug-ins in modules
Puppet supports several kinds of plug-ins, which are distributed in modules. These plug-ins enable features such as custom facts and functions for managing your nodes. Modules that you download from the Forge can include these kinds of plug-ins, and you can also develop your own.
When you install a module that contains plug-ins, they are automatically enabled. At the start of every Puppet run, Puppet Server loads all the plug-ins available in the environment's modulepath. Agents download those plug-ins, so module plug-ins are available for use on the first Puppet run after you install them in an environment.
Plug-ins are available whether or not a node uses classes or defined
types from a given module. In other words, even if you don't declare any classes from
the stdlib module, nodes
still use the stdlib
custom facts. There is no way to exclude plug-ins in an environment in which they are
installed.
If the agent and primary server are both running Puppet 5.3.4 or newer, the agent also downloads any non-English translations included in the module.
Puppet supports several kinds of plug-ins. Puppet looks for each plug-in in a different subdirectory of the module. If you are adding plug-ins to a module, be sure to place them in the correct module subdirectory. In all cases, you must name files and additional subdirectories according to the plug-in type's loading requirements.
Environments aren't completely isolated for certain kinds of plug-ins. If you are using custom resource types or legacy custom functions, you can encounter conflicts if your environments contain differing versions of a given plug-in.In such cases, Puppet loads the first version it encounters of the plug-in, and then continues to use that version for all environments.
To avoid plug-in conflicts for resource
types, use the puppet
generate types command as described in the environment isolation
documentation. To fix issues with legacy custom functions, rewrite them with the
modern API, which is not affected by this issue.
Module plug-in types
Modules can contain different types of plug-ins, each in a specific subdirectory.
| Plug-in | Description | Used by | Module subdirectory |
|---|---|---|---|
| Custom facts | Written in Ruby, facts can provide a specified piece of information about system state. For information about writing custom facts, see the Facter custom facts documentation. | Agents only. | lib/facter |
| External facts | External facts provide a way to use arbitrary executables or scripts as facts, or set facts statically with structured data. For information about external facts, see the Facter custom facts documentation. | Agents only. | facts.d |
| Puppet functions | Functions written in Puppet to return calculated values. For more information, see the topic about writing custom functions in Puppet. | Puppet Server only. | functions |
| Ruby functions | Functions written in Ruby to return calculated values.
Modern Ruby functions are written
for the Puppet::Functions API. |
Puppet Server only. | lib/puppet/functions |
| Resource API | The Resource API is built on top of Puppet core and is useful for creating custom types and providers. For more information about the Resource API, visit Develop types and providers with the Resource API. | Puppet Server and agents. |
lib/puppet/type, lib/puppet/provider, lib/puppet/transport, lib/puppet/util
|
| Resource types | Written in Puppet to add new resource types to Puppet. For information about developing resource types, see custom types documentation. | Puppet Server and agents. | lib/puppet/type |
| Resource providers | Written in Puppet to add new resource providers to Puppet. For information about developing resource providers, see the custom providers documentation. | Puppet Server and agents. | lib/puppet/provider |
| Augeas lenses | Augeas provides a way to modify config files. To learn more about using Augeas with Puppet, see the Forge for Augeas tips and tricks. | Agents only. | lib/augeas/lenses |