Puppet

Puppet is a cross platform framework enabling system administrators to perform common tasks using code. The code can do a variety of tasks from installing new software, to checking file permissions, or updating user accounts. Puppet is great not only during the initial installation of a system, but also throughout the system's entire life cycle. In most circumstances puppet will be used in a client/server configuration.

This section will cover installing and configuring Puppet in a client/server configuration. This simple example will demonstrate how to install Apache using Puppet.

Preconfiguration

Prior to configuring puppet you may want to add a DNS CNAME record for puppet.example.com, where example.com is your domain. By default Puppet clients check DNS for puppet.example.com as the puppet server name, or Puppet Master. See Domain Name Service (DNS) for more DNS details.

If you do not wish to use DNS, you can add entries to the server and client /etc/hosts file. For example, in the Puppet server's /etc/hosts file add:

127.0.0.1 localhost.localdomain localhost puppet
192.168.1.17 puppetclient.example.com puppetclient

On each Puppet client, add an entry for the server:

192.168.1.16 puppetmaster.example.com puppetmaster puppet

Replace the example IP addresses and domain names above with your actual server and client addresses and domain names.

Installation

To install Puppet, in a terminal on the server enter:

sudo apt install puppetmaster

On the client machine, or machines, enter:

sudo apt install puppet

Configuration

Create a folder path for the apache2 class:

  sudo mkdir -p /etc/puppet/modules/apache2/manifests

Now setup some resources for apache2. Create a file /etc/puppet/modules/apache2/manifests/init.pp containing the following:

class apache2 {
  package { 'apache2':
    ensure => installed,
  }

  service { 'apache2':
    ensure  => true,
    enable  => true,
    require => Package['apache2'],
  }
}

Next, create a node file /etc/puppet/manifests/site.pp with:

node 'puppetclient.example.com' {
   include apache2
}

Replace puppetclient.example.com with your actual Puppet client's host name.

The final step for this simple Puppet server is to restart the daemon:

sudo systemctl restart puppetmaster.service

Now everything is configured on the Puppet server, it is time to configure the client.

First, configure the Puppet agent daemon to start. Edit /etc/default/puppet, changing START to yes:

START=yes

Then start the service:

sudo systemctl start puppet.service

View the client cert fingerprint

sudo puppet agent --fingerprint

Back on the Puppet server, view pending certificate signing requests:

sudo puppet cert list

On the Puppet server, verify the fingerprint of the client and sign puppetclient's cert:

sudo puppet cert sign puppetclient.example.com

On the Puppet client, run the puppet agent manually in the foreground. This step isn't strictly speaking necessary, but it is the best way to test and debug the puppet service.

sudo puppet agent --test

Check /var/log/syslog on both hosts for any errors with the configuration. If all goes well the apache2 package and it's dependencies will be installed on the Puppet client.

This example is very simple, and does not highlight many of Puppet's features and benefits. For more information see Resources.

Resources