Configuration: How Puppet is Configured
Puppet’s commands and services can be extensively configured, and its settings can be specified in a variety of places.
This page is an overview of how Puppet’s configuration works.
How Puppet Loads Settings
What are These Settings?
Here they are:
Settings are Loaded on Startup
When any Puppet command or service starts up, it gets values for all of its settings. Any of these settings may change the way that command or service behaves.
A command or service will only read its settings once; if it needs to be reconfigured, it will need to be restarted or run again.
Settings can be set on the Command Line
When a Puppet command or service is started, you can specify any setting as a command line option, using two hyphens and the name of the setting:
$ sudo puppet agent --test --noop --certname temporary-name.example.com
Settings from the command line have top priority, and will always override settings from the config file.
(When running under Rack, the Puppet master service can have command line options set in its
config.ru file. For the Puppet agent service, you can often edit the init script to add command line options. In both cases, this is really only useful for the
vardir settings, which can’t be set in puppet.conf.)
For most settings, you specify the option and follow it with a value. An equals sign between the two (
=) is optional, and values may optionally be surrounded by quotes.
All three of these are equivalent to setting
certname = temporary-name.example.com in puppet.conf.
For settings whose only valid values are
false, you use a shorter format instead. Specify the option alone to set the setting to
true, or prefix the option with
no- to set it to false. That is:
--noop is equivalent to setting
noop = true in puppet.conf.
--no-noop is equivalent to setting
noop = false in puppet.conf.
Settings can be set in the Main Config File
Puppet’s main config file is called
puppet.conf. Its format and behavior are described in full on a separate page.
Settings Have Default Values
If a setting isn’t specified on the command line or in puppet.conf, it will fall back to a default value. Default values for all settings are listed in the configuration reference.
Some of these default values are based on other settings — when this is the case, the default is shown using the other setting as a variable (e.g.
Main Settings vs. Extra Config Files
When we mention “settings” in the context of Puppet, we usually mean the main settings. These are the settings that are listed in the configuration reference (short list, long list). They are valid in puppet.conf and available for use on the command line. These settings configure nearly all of Puppet’s core features.
- The main settings only support a few types of values. Some things just can’t be configured without complex data structures, so they needed separate files. (Authorization rules and custom CSR attributes are in this category.)
- Puppet currently doesn’t allow extensions to add new settings to puppet.conf. This means some settings that should be main settings (like the PuppetDB server) can’t be.