Red Hat Enterprise Linux 7 has already been available for over 8 months, but is still fairly new. We will be using it as a base for our upcoming tutorials, so it is important to learn how to install it. The instruction below will work with CentOS 7.2 as well.
Installation procedure is a bit different from the previous line of RHEL 6.x. While Red Hat 6 used a wizard style installer, RHEL 7 offers a control panel style choice during installation, and each step can be configured in any order. Well, almost. The post installation settings like root password or user accounts can be configured while the OS is already being installed – which saves some time.
First, obtain the RHEL ISO image from access.redhat.com. You can request an evaluation license, if you don’t have one already. At the time of writing this post, the last generally available RHEL 7 is version 7.2.
Once the machine is started, you will see this boot screen:
In the next step choose the language to be installed and approprioate keyboard layout to be used in the installer (actual languages to be installed will be chosen later).
We will start with timezone. Click DATE & TIME to customize your settings. A window with timezone map will appear. You can either use “Region” and “City” dropdown lists to find your region, or click appropriate location on the map. You can also choose to set up NTP here – simply enable “Network Time“.
In the next step, we will set up security policies. On the Installation Summary screen click SECURITY POLICY. In the window that follows, choose appropriate security profile. We’ve used “Standard System Security Profile” for our installation.
You can choose to disable security policy, but we strongly discourage it. It’s better to design applications with the security policy already in place, rather than customize the policy after the application is already running.
In the next step you can choose the packages to be installed. When setting up a specific application it’s best to use Minimal Install and then install only the required packages using yum. Optionally you can choose a pre-configured set of packages, so your system doesn’t require additional customization after installation.
The next step is an important one. Disk partitioning tells the installer how to divide the available disk space, and mistakes made at this step will impact the system later. Unless you have a specific partitioning scheme for the application you want to install on your RHEL server, you can let the installer partition the disk for you.
If you wish to customize your partitions, scroll the INSTALLATION DESTINATION window down, so you can see Other Storage Options, and de-select automatic partitioning. You will be able to customize the partition options on the next screen:
Second, consider your application and user needs when assigning space for partitions. According to Red Hat Documentation, recommended partitioning scheme is:
|Partition||Minimum recommended size|
* see Red Hat Documentation for recommended swap sizes depending on server RAM amount
Once all partitions have been selected, you can proceed by clicking “Done”. Installer will list the disk operations which will be executed by the installer. WARNING: this will destroy existing data on the destination disk.
The next step is enabling Network and setting up host name. First, choose NETWORK & HOST NAME on the Installation Summary screen. For now it’s enough to enter a host name on the bottom of the window. Next step on this screen is enabling the network adapter by switching the switch to “ON” position. The default setting is to use automatic IP address provided by DHCP, but you can choose to enter a manual IP address by clicking “Configure…”
In the following step we will set the Kernel Dump memory. This is a small amount of system RAM reserved specifically for kernel crash, and will help Red Hat determine the cause of eventual kernel panic. If you have limited amount of RAM in your server, you can cosnider disabling it. Otherwise, leave it enabled.
When ready, press Done.
That’s it, we’re ready for installation! Click “Begin Installation” to continue with installation.
We recommend hardening your OS right away, which means disabling root account in sshd settings (a tutorial on how to do it is coming) and using unprivileged user accoutns to access the system. Administrative tasks can ten be performed by the use of su or sudo. Because of what was just said, you should create at least one unprivileged user account.
Once the system finished installing, it will reboot and let you use your brand new RHEL 7.