In this first chapter, we will start off by looking at Jenkins from several different perspectives; how to obtain and run it, some of the ways and the reasons people use it, and what it provides to them. In doing so, we will take a look at some standard use cases and examine how a Jenkins installation will often evolve over a period of time—typically starting off with only the basic installation and core features, then progressively becoming more customized and advanced with different types of extensions. We will start off with "ready-made" plugins, and then progress towards extending these before looking at how to develop your own plugins.

We will then summarize the high-level aims of this book, and give the details of what you should hopefully gain from them.

We will provide an overview of the various tools and the environment setup that you will need in order to run the practical examples covered in the subsequent chapters, and we will review the best practices of Continuous Integration (CI) by identifying some of the ways that Jenkins can be used to achieve them.

Throughout this book, it is assumed that you already have some working knowledge of Jenkins, so we will not spend much time covering the basics, such as installing and starting Jenkins, or detailing the usage of standard features and core functions.

If you would like more details on these topics, there are numerous helpful tutorials and examples available online; the Use Jenkins section of the Jenkins homepage, https://jenkins-ci.org, is often a good starting point for help with general setup and usage questions.