The best way to get started is by having an SLES 16 virtual machine to work with. You may do so on your main computer or in the cloud. In the following sections of this chapter, we will review both options, and you will be able to run your own SLES 16 system.

Obtaining the SLES software and a subscription

To be able to deploy SLES, it is recommended that you obtain a SUSE subscription. Even when you can download images without a subscription, it is recommended to get one to access repositories with software and updates. You can get, free of cost, an Evaluation subscription...

For this section of this chapter, we will follow the typical installation process to have SLES installed on a machine. We will follow the default steps, reviewing the options available for each one.

Preparation for a physical server installation

A physical server requires some initial setup before starting the installation. Some common steps include configuring the disks in the internal array, connecting the server to the networks and preparing the switches for any interface aggregation that is expected (teaming, bonding), preparing access to external disk arrays (i.e., fiber-channel arrays), setting up out-of-band capabilities, and securing the BIOS/UEFI configuration.

We will not get into the details of these preparations, except for the boot sequence. The server will require booting (start loading the system) from an external device such as a USB thumb drive or optical disk (whether physical or emulated through the out-of-band capabilities).

To...

Once we have prepared our virtual or physical server for installation, it’s time to proceed with it. We will know that all the previous steps were taken correctly if we arrive at the following screen:

Figure 1.17 – Initial boot screen for SLES 16 installation

We are offered five options (selected one in green):

• Boot from Hard Disk: This will boot from the existing hard disk, with the existing OS, in case you don’t want to install at that time. This means that if you boot from the USB accidentally on a system that has an OS, it will boot from the existing OS instead of launching the installation.
• Install SUSE SLE 16: This option will boot and run the installer. You will have to select it to start the installation.
• Failsafe -- Install SUSE SLE 16: This option will boot and run the installer in failsafe mode. This is to be used in case the general installation option fails.
• Check Installation...

Deploying SLES on the cloud is slightly different from the process shown before, as cloud providers produce some of the capabilities on your behalf. Let’s look at what these differences are:

• You don’t use an ISO image or Agama for the deployment, but a pre-configured image that is already prepared and made available by the cloud provider.
• The image is customized and adapted to our needs after creation. You will not be able to choose the configuration details of the system during installation time (i.e., selecting a time zone), but afterwards, using the first boot configuration.
• There is an automated mechanism to perform those change settings, such as adding a user and credentials to access the system or configuring the network.
• The most extended and well-known mechanism used by cloud providers to do so is cloud-init.
• Images delivered by cloud providers include cloud-init software.
• Systems are usually...

SLES installations have many options to choose from, and they should be tailored for the use case. However, some common recommendations apply. Let’s see the most common types.

The first type is blueprints:

• Standardize the core installation and create a blueprint for it.

This blueprint shall be minimal enough to serve as the base for all other blueprints and deployments.

• Build a set of blueprints for common cases when needed.
• Try to use an automation platform to build extended cases (i.e., Salt or Ansible):
• Try to make the cases modular (i.e., app server and database blueprints can be combined on one single machine).
• Be aware of the requirements to apply your templated blueprints and adapt to the environments you will use.

The second type is software:

• The less software is installed, the smaller the attack surface. Try to keep servers with the minimal set of packages required...

The SUSE Certified System Administrator exam is completely practical, based on real-world experience. The best way to prepare for it is by practicing as much as possible; that is why this book starts by providing access to SLES 16 and provides alternatives for how to deploy your own VMs.

There are different scenarios covered for the installation, which are the most common ones, and include using a physical machine, a virtual machine, or a cloud instance.

When using physical hardware, we focus on the fact that many people like to reuse old hardware, buy second-hand or cheap mini servers, or even use their laptop as the main installation device/platform for their Linux experience.

For virtual machines, we think about the people who want to keep all their work on the same laptop but without messing with their current operating system (which may not even be Linux). This could also work well with the previous option by having virtual machines on your own mini server...