Puppet with Docker: How I Tested Master and Agent

What I Did

I wanted to try Puppet without dedicating two full VMs. I ran a Puppet master and agent in separate Ubuntu Docker containers on my machine. Docker host commands work the same on Ubuntu and Arch.

Installing Puppet Master

1. Download the Ubuntu image:

   sudo docker pull ubuntu
   

2. Create a container for Puppet master:

   sudo docker run --name puppet-master -it ubuntu
   exit
   

3. Start the container:

   sudo docker start puppet-master
   

4. Open the bash shell of the Puppet master container:

   sudo docker exec -it puppet-master bash
   

5. Update and upgrade the container:

   apt update
   apt upgrade
   

6. Install necessary tools:

   apt install nano inetutils-ping net-tools wget -y
   

7. Add the Puppet repository:

   wget https://apt.puppetlabs.com/puppet7-release-focal.deb
   dpkg -i puppet7-release-focal.deb
   apt update
   

8. Create an image of the configured container:

   exit
   sudo docker commit puppet-master puppet-7
   

9. Confirm the image creation:

   sudo docker images
   

10. Install Puppet server:

    sudo docker exec -it puppet-master bash
    apt install puppetserver
    

11. Modify memory allocation for Java in Puppet server configuration:

    nano /etc/default/puppetserver
    

    Replace:

    JAVA_ARGS="-Xms2g -Xmx2g"
    

    With:

    JAVA_ARGS="-Xms64m -Xmx512m"
    

12. Create a certificate authority:

    /opt/puppetlabs/bin/puppetserver ca setup
    

13. Start the Puppet server:

    service puppetserver start
    

14. Add Puppet to the system path:

    echo 'PATH=$PATH:/opt/puppetlabs/bin' >> ~/.bashrc
    source ~/.bashrc
    

15. Retrieve the fully qualified domain name (FQDN):

    facter -p | grep fqdn
    

Installing the Puppet Agent

1. Create a container for the Puppet agent using the previously created image:

   sudo docker run --name puppet-agent -it puppet-7
   exit
   

2. Start the Puppet agent container:

   sudo docker start puppet-agent
   

3. Open the bash shell of the Puppet agent container:

   sudo docker exec -it puppet-agent bash
   

4. Install Puppet agent:

   apt install puppet-agent
   

5. Add Puppet to the system path:

   echo 'PATH=$PATH:/opt/puppetlabs/bin' >> ~/.bashrc
   source ~/.bashrc
   

Configuring Puppet Master and Puppet Agent

Configuring the Puppet Agent

1. Edit the hosts file:

   nano /etc/hosts
   

2. Add the IP address of the Puppet master container along with its FQDN.

3. Check the connection:

   ping <your fqdn>
   

Configuring the Puppet Master

1. Sign certificates of all agents:

   nano /etc/puppetlabs/puppet/puppet.conf
   

2. Add the following line:

   autosign=true
   service puppetserver restart
   

3. Verify the connection:

   puppet agent --test --server <fqdn>
   

If the connection is established successfully, the output should indicate no errors.