Dive into the options for installing CentOS.
- [Instructor] If you're CentOS from scratch, you will need to start with an installation image. You can download an installer from centos.org/download. At the time that I am recording this, there are two buttons on the screen for ISO images, or disk images. There is a DVD image which is around four gigabytes and will fit on a four gig flash drive or DVD-R. And the minimal ISO which includes only the bare minimum to get a CentOS system up and running, and what's in it, just over 900 megabytes. I will choose the DVD one because it will give us what we need and because it offers the other roles that we'll see later on which is helpful for exploring. We'll start with a basics and build up though. You download these images through your browser or you can get a torrent download as well. Instead of having one server hosting the installer files, many Linux distribution use mirrors, which are servers scattered throughout the world. Each with a copy of the files that people need to download. This reduces load and can make the download for the end user. There is an HTTP link for each of the mirrors. I will click on a file from a mirror that looks like it's near me. If you choose a mirror near you, it's likely that you will get a faster download speed. On the download page there is also a link to alternative installers if you need to use a different architecture or something. But I won't be covering those here. If you're installing from scratch on a physical or virtual machine, you can pick one of many different configurations. And you can switch between configurations later too. If you're using an installation of CentOS on a cloud service such as Azure, DigitalOcean or Amazon, you will typically be limited to whatever options the image provider has decided to offer to start out. Let's take a look at the base environments offered out of the box. You don't need to memorize these or write them down. They will show up in the installer that we'll see later on. I just want to give you an idea of what's available before we start installing. The minimal install offers what CentOS calls basic functionality. This is a command line environment with pretty basic tools. It's a good place to start if you're deploying a very customized or very lean environment where you want to only specifically install what you want to have. This is what we'll use so we can build up our system as we learn about CentOS. Infrastructure server is similar to a basic environment in that it offers command line functionality. And within it there are options to install packages to make it a backup server, DNS server, directory server, email server, file server, print server and more. You can also add support for overutilization, hardware monitoring and high availability. This is commonly used when deploying a particular kind of server into a data center or somewhere that it will be running without a display, mouse or keyboard and access too for the network. File and print server is a command line environment and it installs packages for those services. Basic web server starts out with packages for being a web server and allows you to add various languages and database options during the installation. Virtualization host is available to set the machine up for being a VM hypervisor. Server with GUI sets the machine up with a desktop environment and allows you to choose various packages to support different server roles. This is effectively what we'll be setting up throughout the course as we add some services and eventually set up a desktop ourselves. GNOME desktop and KDE Plasma workstation configure the machine to have GUI app of either type. And they offer the opportunity to install internet and productivity applications. This will probably be what you would choose if you want to switch your workstation over to running CentOS to practice with it. Development and creative workstation allow the installation of graphics, development, writing and productivity tools during install. This also is a good option for trying out CentOS on a desktop or laptop. These base environments are starting points for installations. As I mentioned earlier we'll start with minimal and build up from there. We also need to consider where we are going to run the CentOS installation. I mentioned earlier that CentOS is popular for servers and a server might run in the cloud or in a data center. You can also run CentOS on a desktop or laptop computer or inside of a virtual machine. Throughout the rest of this chapter I'll show you how to install CentOS on a virtual machine, if you want to install the OS that way, and on a physical computer, which is what I will be using in the course. If you plan to use a cloud server, you'll need to get that provisioned and configured for remote access on your own. Most cloud providers make this fairly straightforward, but because different providers operate in different ways, I can't cover them here.
- What is CentOS?
- Installing CentOS
- Configuring networking manually
- Configuring the network with NetworkManager
- Connecting remotely
- Working with security-enhanced Linux (SELinux)
- Setting up a firewall
- Setting up a web server
- Sharing user home folders with Samba
- Setting up a desktop environment