This book will not teach you DevOps practices. It will not show you how Docker works. It will not explore how to build images, deploy services, operate Swarm clusters, nor how to do continuous deployment. We will not develop microservices nor will we go through practices and tools that allow us to create and manage our infrastructure. This book assumes that you already know all that. If you do not, please read The DevOps 2.0 Toolkit: Automating the Continuous Deployment Pipeline with Containerized Microservices for a general overview of DevOps tools and practices and The DevOps 2.1 Toolkit: Docker Swarm: Building, testing, deploying, and monitoring services inside Docker Swarm clusters for an in depth examination of how Docker Swarm clusters work.

Now that you know what this book is NOT about, you are probably wondering what it is. Well... I don't know yet. I decided to skip the planning and just start coding and writing about solutions that go beyond a simple cluster management and deployment of services. The objective is to create a self-adapting and self-healing system. That's all I know for now. I'm not sure how I will do it nor whether I will succeed. What I do know is that I will write down every step of the journey.

While there will be a lot of theory, this is a hands-on book. You won't be able to complete it by reading it in a metro on the way to work. You'll have to read this book while in front of a computer getting your hands dirty. Eventually, you might get stuck and in need of help. Or you might want to write a review or comment on the book's content. Please join the DevOps20 (http://slack.devops20toolkit.com/) Slack channel and post your thoughts, ask questions, or simply participate in a discussion. If you prefer a more one-on-one communication, you can use Slack to send me a private message or send an email to [email protected]. All the books I wrote are very dear to me, and I want you to have a good experience reading them. Part of that experience is the option to reach out to me. Don't be shy.

Please note that this, just as the previous book, is self-published. I believe that having no intermediaries between the writer and the reader is the best way to go. It allows me to write faster, update the book more frequently, and have a more direct communication with you. Your feedback is part of the process. No matter whether you purchased the book while only a few or all chapters were written, the idea is that it will never be truly finished. As time passes, it will require updates so that it is aligned with the change in technology or processes. When possible, I will try to keep it up to date and release updates whenever that makes sense. Eventually, things might change so much that updates are not a good option anymore, and that will be a sign that a whole new book is required. I will keep writing as long as I continue getting your support.

You can download the example code files for this book from your account at www.packtpub.com. If you purchased this book elsewhere, you can visit www.packtpub.com/support and register to have the files emailed directly to you.

You can download the code files by following these steps:

1. Log in or register at www.packtpub.com.
2. Select the SUPPORT tab.
3. Click on Code Downloads & Errata.
4. Enter the name of the book in the Search box and follow the onscreen instructions.

Once the file is downloaded, please make sure that you unzip or extract the folder using the latest version of:

• WinRAR/7-Zip for Windows
• Zipeg/iZip/UnRarX for Mac
• 7-Zip/PeaZip for Linux

The code bundle for the book is also hosted on GitHub at https://github.com/PacktPublishing/The-DevOps-2.2-Toolkit. We also have other code bundles from our rich catalog of books and videos available at https://github.com/PacktPublishing/. Check them out!

We also provide a PDF file that has color images of the screenshots/diagrams used in this book. You can download it here: http://www.packtpub.com/sites/default/files/downloads/TheDevOps2.2Toolkit_ColorImages.pdf.

There are a number of text conventions used throughout this book.

CodeInText: Indicates code words in text, database table names, folder names, filenames, file extensions, pathnames, dummy URLs, user input, and Twitter handles. Here is an example: "Mount the downloaded WebStorm-10*.dmg disk image file as another disk in your system."

A block of code is set as follows:

 docker service create \
     --name util \
     --network monitor \
     --mode global \
     alpine sleep 100000000

When we wish to draw your attention to a particular part of a code block, the relevant lines or items are set in bold:

docker service create \
    --name util \
    --network monitor \
    --mode global \
    alpine sleep 100000000

Any command-line input or output is written as follows:

docker container exec -it $ID \
    curl node-exporter:9100/metrics

Bold: Indicates a new term, an important word, or words that you see onscreen. For example, words in menus or dialog boxes appear in the text like this. Here is an example: " Depending on the view, you should see three values in Console or three lines in
the Graph tab"