Puppet for Containerization

Let's install Vagrant. Firstly, we will need our virtualization backend, so let's download and install VirtualBox. At the time of writing, we use VirtualBox 5.0.10 r104061. If that's outdated by the time you read this book, just grab the latest version.

You can download VirtualBox from https://www.virtualbox.org/wiki/Downloads. Choose the version for your OS, as shown in the following screenshot:

Once the package is downloaded, follow the given installation process for your OS.

VirtualBox

Follow these steps to install Vagrant on Mac OSX:

1. Go to your Downloads folder and double-click on VirtualBox.xxx.xxx.dmg. The following installation box will pop up:

   

2. Then, click on VirtualBox.pkg. Move on to the next step, as shown in the following screenshot:

   

   The installer will then check whether the software is compatible with the Mac OSX version.

3. After this, click on Continue. Once the check is successful, we can move on to the next step:

   

4. We then choose the default location for the installation and click on Install.

5. Then, enter your admin password and click on Install Software:

   

The installation is now complete. The following screenshot shows what the screen looks like after completing the installation:

Now that we have the virtualization backend, we can install Vagrant:

Note

At the time of writing this book, we are going to use Vagrant 1.7.4; if that is no longer the latest version, please grab the latest one. You can find this version of Vagrant at https://www.vagrantup.com/downloads.html. Again, download the installation package for your OS.

Now that we have a fully working Vagrant environment, we can start with and look at how Vagrant works and how we are going to provision our machines. As this book is not about Vagrant, we won't be writing a Vagrantfile from scratch. Instead, I have created a Vagrantfile that we will be using throughout the book:

Let's look at the Vagrantfile construct:

As you can see from the preceding screenshot, the Vagrantfile is actually a Ruby file. As it is Ruby, it opens up a world of opportunities for us to make our code elegant and efficient. So, in this Vagrantfile, we have extracted all the low-level configurations and replaced them with a few parameters. Why are we doing this? The reason is to split up our logic from our configuration and also iterate our configuration in order to stop replication of our code. So, where is all the configuration stored? The answer is in the servers.yaml file. This is where we set the vagrant box that we want to deploy, the number of CPUs for the box, the internal network's IP, the hostname, the forwarded ports between the guest and host, and the RAM and shell provider for bash commands that we need to get the environment ready for Puppet to run, for example, downloading modules and their dependencies from the Puppet Forge:

The benefit of this approach is also that any developer using a Vagrantfile does not need to actually modify the logic in the Vagrantfile. They only need to update the configuration in servers.yaml. As we go through the book, we will work with the other files in the repository, such as Puppetfile, hieradata, and manifests. Now that we have set up our Vagrant environment, let's look at how to get our Puppet modules from the Puppet Forge.

One of the great things about puppetlabs and their products is the community. If you ever get a chance to attend PuppetConf or a Puppet Camp, depending on where you live, I would really recommend you to attend it. There will be a wealth of knowledge there and you will meet some really great people.

The Puppet Forge is a website that puppetlabs runs. It is a place where other Puppet developers publish modules that are ready to use. You might be asking, what about GitHub? Can't you get modules from there? Yes, you can. The difference between the Puppet Forge and GitHub is that the Puppet Forge is the stable, releasable version of the module, whereas GitHub is the place to contribute to the module, that is, a place to create pull requests.

The following screenshot shows the home page of Puppet Forge:

Now that we have been introduced to the Puppet Forge, let's use it to find our Docker module that we will be using to build our environment.

Now that we have selected our module, we can move on to setting up our puppetfile:

In the previous topic, we cloned our Vagrant template using Git. In that repo, there is also a puppetfile. A puppetfile is used as a control file for our modules. It will list all the modules that we need (in this instance, just to install Docker). r10k will then reference the puppetfile and pull the modules from the Puppet Forge into our environment's directory.

As modules have dependencies, we need to make sure that we capture them in our puppetfile. For the Docker module, we have three dependencies: puppetlabs/stdlib (>= 4.1.0), puppetlabs/apt (>= 1.8.0 <= 3.0.0), and stahnma/epel (>= 0.0.6), as shown in the following screenshot.

Now, we know all the modules that we need to build a Docker environment. We just need to add them to our puppetfile.

The following screenshot is an example of what the puppetfile should look like:

Now, when we run vagrant up, r10k will pull the modules from the Puppet Forge. We invoke r10k on line 13 of servers.yaml with the r10k puppetfile install—verbose command. The following screenshot shows the output of this command:

If we are successful, the terminal will provide the following output:

Now that we have our puppetfile set up, we can install Docker.

The first thing that we need to do to install Docker is set our manifest to include the Docker class on our node. To do this, let's go to our Vagrant repo. In the repo, there is a file in the manifests directory called default.pp. We need to edit the file to include the Docker class node 'node-01' { include docker}. We can now save the file, and we are ready to run our environment.

The first step is to open our terminal and change to root of the Vagrant repo. Then, we need to enter the vagrant up command:

This will now provide us with our CentOS 7 box. Install r10k and then run Puppet and apply the Docker class. This will take about 4 minutes depending on your laptop and network connection. If the box was provisioned successfully, you will see the following output:

We can also verify that the Docker installation was successful by logging in to the box via SSH. We will do that with the vagrant ssh command. Once we are in, we will sudo up to root (sudo -i). Now, let's just check whether Docker is installed with the docker command.

You will see the following output on the terminal: