As mentioned, we will need a Virtual Machine. We are going to use Oracle VM VirtualBox to host our VMs, which you can download at: https://www.virtualbox.org (I have downloaded the VirtualBox 5.1.12 platform package for Windows). Download the version that is applicable to you on the downloads page and install it on your computer. I've left all the defaults as they were, but you can change them as you see fit (at your own risk). If all goes well, you should soon see the Oracle VM VirtualBox Manager, as follows:

To create a new VM, click the New button. You then get to pick a name (I have called my VM CI server), a type (Linux), and a version (Ubuntu (64-bit), which is the default). The next window lets you specify the amount of memory. The default is 1 GB, but I recommend making that 4 GB (4096 MB), unless you are only going to run GitLab on it...

The first thing we have to do is install Git. As I said at the start of Chapter 1, Continuous Integration, Delivery, and Deployment Foundations, CI starts with a shared repository and this is it. Git is the immensely popular Source Control Management (SCM) tool from the creator of Linux. It shows that everything is done through the command line, and the only official user interface is so bad you might as well use the command line. Luckily, there are some third-party tools available. Aside from the tooling, Git is a really good source control system that has some benefits over its competitors. As I mentioned earlier, we are going to use GitLab (https://gitlab.com) on Ubuntu, which gives you a nice GitHub-like portal.

In this section, we are going to install Jenkins and configure it from the host machine. We do not need to install Jenkins on a server, so if you are low on RAM, consider installing it on your local machine (see the Installing Jenkins on Windows section). Of course, since you will be using CI mostly in a team, installing Jenkins on your local machine does not make much sense. However, if your company is running Windows servers, or developing using Microsoft technology, you will want to read the Windows section anyway. Unlike Git, Jenkins does not need a client application.

Unfortunately, Jenkins is not as straightforward as doing apt-get install. If you try to install Jenkins...

PostgreSQL (https://www.postgresql.org/) is a powerful and popular open source SQL database. Even though it has nothing to do with Continuous Integration, we will need it to install the next tool, SonarQube. We will make use of PostgreSQL in the later chapters of the book, so we are not going through all this trouble just for SonarQube (but trust me, SonarQube alone is already worth it!).

First, we need to install PostgreSQL and some popular extensions. Ubuntu has some pretty good documentation on how to install PostgreSQL (https://help.ubuntu.com/community/PostgreSQL):

sudo apt-get update
sudo apt-get install postgresql postgresql-contrib

The installation creates a default...

SonarQube (https://www.sonarqube.org/) is a tool that scans your code and does a quality check. A set of rules are applied to your code and every time you break a rule, SonarQube will report it and add it to the technical debt. A rule can be simple, such as a missing semi-colon at the end of a JavaScript line. That should be a few seconds fix. Another rule can be more difficult, such as that the complexity of a function (nested loop and if statements and the lines of code add to the complexity) should not be greater than a certain value. SonarQube has a default set of rules, but you can roll out your own. In this book, we are going to see SonarQube with HTML, CSS, JavaScript, and C#, but SonarQube supports many languages, such as Java, VB.NET, SQL, Haskell, PHP, and many more.

In this chapter, we have installed our CI environment. We have discussed the various tools we are going to use throughout the book. We have also had our first look at Git, Jenkins, and SonarQube and made them work together. In the remainder of the book, we are going to install many more tools on the server and locally. But before we get to that, we will take a closer look at Git in the next chapter, as there is a lot more to Git than we have seen so far.