Puppet Automation

Introduction

Puppet is a systems configuration management platform. Its typical usecase is for server configuration from a centralized puppet server. Puppet may operate in one of three modes:

Client/server mode, useful for managing a large fleet of servers.
Standalone mode with a local module-base, or directory of importable puppet resources; useful when there are a lot of individual resources to manage.
Standalone mode from a single file; useful for smaller-in-scope manifests which may be contained in a single file.

Of these three modes, the third is used. As the set of standalone manifests grows, there may come a time where it makes sense to provide a local module-base.

The basic operation of puppet is to source configuration directives (known as a manifest), calculate a catalog of applicable changes, and then apply the catalog. Puppet supports a dry-run mode wherein the catalog of changes are enumerated without application.

For more information about puppet, or its configuration syntax, see http://puppet.com

Standalone Invocation

Normally, puppet files end in an extension of .pp. Operating in single-file standalone mode, puppet may be invoked using:

puppet apply path/to/my-manifest.pp

Puppet will calculate the catalog, and then attempt to apply the changes therein. Puppet itself requires no special permissions beyond the necessary permissions to manipulate the catalog resources. I.e. if a root-owned file/service/etc is managed, puppet needs to be run as root to affect the necessary delta.

If no file is provided via argv, puppet will attempt to read the manifest from stdin.

To run in dry-run mode, append the --noop flag using:

puppet apply --noop path/to/my-manifest.pp

This will calculate the catalog without actually applying any of the contained changes. Typically, puppet need not run as root in dry-run mode unless root privileges are required to calculate the catalog (e.g. read contents of files owned by root with no read permissions).

In either mode, puppet will fail early if the manifest contains any kind of syntax error.

Developer Guide

See http://puppet.com for a description of the puppet language.

Please run puppet-lint against any changes to puppet files and ensure there are no findings.

Since you happen to be looking at a document about puppet, here's an example manifest wrapped in a cli invocation which ensures puppet-lint is installed on the local system:

sudo puppet apply <<EOF
package { 'puppet-lint':
  ensure => present,
}
EOF