To support the learning of Ansible, I suggest having a machine where you can install Vagrant. Using Vagrant will allow you to try many operations, even destructive ones, without fear.

Additionally, AWS and Azure accounts are suggested, since some examples will be on those platforms.

All examples in this book are available in the GitHub repository at https://github.com/PacktPublishing/-Learning-Ansible-2.X-Third-Edition/.

IT automation is – in its broader sense – the processes and software that help with the management of the IT infrastructure (servers, networking, and storage). In the current shift, we are supporting for a huge implementation of such processes and software.

At the beginning of IT history, there were very few servers, and a lot of people were needed to make them work properly, usually more than one person for each machine. Over the years, servers became more reliable and easier to manage, so it was possible to have multiple servers managed by a single system administrator. In that period, the administrators manually installed the software, upgraded the software manually, and changed the configuration files manually. This was obviously a very labor-intensive and error-prone process, so many administrators started to implement scripts and other means to...

Ansible is an agent-less IT automation tool developed in 2012 by Michael DeHaan, a former Red Hat associate. The Ansible design goals are for it to be minimal, consistent, secure, highly reliable, and easy to learn. The Ansible company was bought by Red Hat in October 2015, and now operates as part of Red Hat, Inc.

Ansible primarily runs in push mode using SSH, but you can also run Ansible using ansible-pull, where you can install Ansible on each agent, download the playbooks locally, and run them on individual machines. If there are a large number of machines (large is a relative term; but in this case, consider it to mean greater than 500), and you plan to deploy updates to the machines in parallel, this might be the right way to go about it. As we discussed before, either agent-full and agent-less systems have their pros and cons.

In the next section, we will...

We will try and compare Ansible with Puppet and Chef during the course of this book, since many people have good experience those tools. We will also point out specifically how Ansible would solve a problem compared to Chef or Puppet.

Ansible, as well as Puppet and Chef, are declarative in nature, and are expected to move a machine to the desired state specified in the configuration. For example, in each of these tools, in order to start a service at a point in time and start it automatically on restart, you would need to write a declarative block or module; every time the tool runs on the machine, it will aspire to obtain the state defined in your playbook (Ansible), cookbook (Chef), or manifest (Puppet).

The difference in the toolset is minimal at a simple level, but as more situations arise and the complexity increases, you will start finding differences between...

Installing Ansible is rather quick and simple. You can use the source code directly, by cloning it from the GitHub project (https://github.com/ansible/ansible); install it using your system's package manager; or use Python's package management tool (pip). You can use Ansible on any Windows or Unix-like system, such as macOS and Linux. Ansible doesn't require any databases, and doesn't need to have any daemons running. This makes it easier to maintain Ansible versions and upgrade without any breaks.

We'd like to call the machine where we will install Ansible our Ansible workstation. Some people also refer to it as the command center.

To be able to learn Ansible, we will need to make quite a few playbooks and run them.

It's possible to create a test environment with cloud providers in a few seconds, but it is often more useful to have those machines locally. To do so, we will use Vagrant, which is a piece of software by Hashicorp that allows users to quickly set up virtual environments independently from the virtualization backend used on the local system. It does support many virtualization backends (in the Vagrant ecosystem these are known as Providers) such as Hyper-V, VirtualBox, Docker, VMWare, and libvirt. This allows you to use the same syntax no matter what operating system or environment you are in.

First we will install vagrant. On Fedora,...

In this chapter, we have already encountered the expression infrastructure code to describe the Ansible code that will create and maintain your infrastructure. We use the expression infrastructure code to distinguish it from the application code, which is the code that composes your applications, websites, and so on. This distinction is needed for clarity, but in the end, both types are a bunch of text files that the software will be able to read and interpret.

For this reason, a version control system will help you a lot. Its main advantages are as follows:

• The ability to have multiple people working simultaneously on the same project.
• The ability to perform code-reviews in a simple way.
• The ability to have multiple branches for multiple environments (that is, dev, test, QA, staging, and production).
• The ability to track a change so that we know when...

For the reasons that we have just seen, and because of its huge popularity, I suggest always using Git for your Ansible repositories.

There are a few suggestions that I always provide to the people I talk to, so that Ansible gets the best out of Git:

• Create environment branches: Creating environment branches, such as dev, prod, test, and stg, will allow you to easily keep track of the different environments and their respective update statuses. I often suggest keeping the master branch for the development environment, since I find that many people are used to pushing new changes directly to the master. If you use a master for a production environment, people can inadvertently push changes in the production environment when they wanted to push them in a development environment.
• Always keep environment branches stable: One of the big advantages of having...

In this chapter, we have seen what IT automation is, its advantages and disadvantages, what kind of tools you can find, and how Ansible fits into this big picture. We have also seen how to install Ansible and how to create a Vagrant virtual machine. In the end, we analyzed the version control systems and spoke about the advantages Git brings to Ansible, if used properly.

In the next chapter, we will start looking at the infrastructure code that we mentioned in this chapter, without explaining exactly what it is and how to write it. We'll also see how to automate simple operations that you probably perform every single day, such as managing users, managing files, and file content.