What you need for this book
This book covers Ubuntu Server in depth, and in order to follow along, you'll need to download Ubuntu Server 16.04 and have a machine or two to practice on. It really doesn't matter if you use virtual or physical machines, as the nature of the machine is irrelevant so long as it can run Ubuntu. Virtual machines have the added benefit of snapshots, which you can use to test and roll back modifications to the server.
In the case of virtual machines, it's recommended to use bridged mode for networking so that each VM can see each other easily over the network. It's a good idea to use multiple machines if you can, since several chapters will include networking concepts, such as connecting to other hosts via SSH, setting up a website, and accessing databases.
You'll need to create bootable media in order to install Ubuntu Server. On physical servers, this will require either a blank CD or empty flash drive. In the first chapter, the installation process will be covered and will include a walkthrough on creating bootable media. Ubuntu Server is available online at http://www.ubuntu.com/server.
Since Ubuntu Server doesn't include a graphical user interface by default, it can run on relatively modest hardware. As long as you have 512 MB of RAM and 8 GB of hard disk space available, you should be in good shape. Raspberry Pi users will need an available SD card, preferably 8 GB or larger. Raspberry Pi models 2 and 3 are supported by Ubuntu Server.
