09 November, 2021 by Oscar Borayn

How To Install KVM On CentOS 8 VPS?

In this article, we will describe the requirements of KVM Hypervisor, Features Of KVM Hypervisor, and the main reason for Install KVM On Linux VPS instead of other VM programs; Then have a fully comprehensive training about the Installation Of KVM on Centos 8.

Table of Contents

About KVM

Right Hypervisor For Your IT Needs In Linux

Kvm virtualizer is available as open-source and built-in Linux; That lets you turn Linux into a hypervisor, also called virtual KVM web server with the dedicated kernel; Allows you to run multiple Linux-based virtual environment guest servers simultaneously; KVM is developed by Red Hat Corporation.

Why KVM?

According to Red Hat: KVM inherits the performance of Linux, scaling to match demand load if the number of guest machines and requests increases. KVM allows the most demanding application workloads to be virtualized and is the basis for many enterprise virtualization setups, such as data centers and private clouds.

Also, the kernel-mode component of KVM is a part of the Linux kernel; So it will be more compatible with Linux in every way and can be highly secure.

Special Features Of KVM Hypervisor

KVM is installed on a Linux operating system or host server. But due to its special technology, it creates virtual servers with its kernel, and this allows you to create a Simulator of the virtual server or any operating system that you need, such as Windows, BSD, Kali Linux, Ubuntu Linux; Also install other operating systems and use it easily.

Given that Linux provides dedicated resources to KVM; As a result, KVM offers high quality for the guest operating system compared to other virtualizers.

Allows the allocation of flexible storage and optimizes the available space for every guest virtual machine

Hosts support up to 160 cores and 2 TB of RAM

Guests support up to 64 vCPUs and 512 GB of RAM

Self Service user portal

Ways To Install KVM On CentOS 8 VPS Step By Step

Step: 1. Installing the virt-install package and virt module.

Step: 2. Validate all the components on your KVM.

Step: 3. Add and enable IOMMU In CentOS 8 kernel Command-Line.

Step: 4. Restart CentOS 8 VPS to apply the changes.

Step: 5. Installing Cockpit Web Interface.

Step: 6. Add support for managing virtual machines via Cockpit.

Step: 7. Go into the Virtual Machines from the left side of the Cockpit Web UI panel, to manage your KVM Virtual Machines.

Note: If you were able to complete step 2, so you do not need to use step 3; Ignore it and continue the installation from step 4.

KVM Requirements

KVM Main Requirements

1) Verify support for Virtual Technology by the CPU:

We have 2 different ways to know that how to check if virtualization is enabled in Linux;

First Way: Using the lscpu command shows CPU architecture information on the server:

lscpu

The output of the first command will be as shown below:

Second Way: If the output of the previous command does not show anything, you can use the following command instead of the previous command to make sure that VT technology is enabled:

lscpu | grep Virtualization

The output of the first command will be as shown below:

Note: If the output ordered in the Virtualization Type section of your putty or command line is different from the output of the images you see; And also is written as VT-x; This means that virtualization technology is enabled for you.

2) Install Putty software and login to the VPS server:

If you do not have experience in using Putty software, you can benefit from the article related to it; You can click on the: How to connect to a Linux VPS using putty to start the installation.

Download Putty: By clicking on the following link: https://www.chiark.greenend.org.uk/~sgtatham/putty/latest.html you can download Putty Software.

KVM Server Requirements

CPU: 3.4 GHz (2 cores)

Memory: 2 GB

Storage: 20 GB

Operating System: CentOS 8.0

Install KVM On CentOS 8 VPS

1. let’s start the installation of KVM on CentOS 8 by installing the virt module:

dnf install -y @virt

After using the command, we will encounter a similar image look like above; That shows the virt module installation has been completed.

— Now we need to install the virt-install package; Which will provide us with some very useful command-line tools:

dnf install -y virt-install

As you can see, the virt-installation package has been installed successfully.

2. Here, we are going to Validate all the components on your KVM;

This command validates that the host is configured in a suitable way to run libvirt hypervisor drivers:

virt-host-validate

If you encounter a similar image and warning errors look like this:

WARN (Unknown if this platform has IOMMU support)
QEMU: Checking for secure guest support :
WARN (Unknown if this platform has Secure Guest support)

That means (input-output memory management unit) support and its components are not yet enabled in the CentOS 8 Kernel.

3. We can use the below command to add and enable IOMMU In CentOS 8 kernel Command-Line:

grub2-editenv - set "$(grub2-editenv - list | grep kernelopts) intel_iommu=on"

According to the image above; Indicates that the command used activates IOMMU automatically.

4. At this time, we need to restart CentOS 8 VPS to apply the changes made to enable IOMMU;

Run the following command:

systemctl reboot

— After restarting, the next command that we will be needed again to use; Is components validating command;

now if you use it again, you will be able to have all the outputs on the pass; Use the below command:

virt-host-validate

[root@server ~]# virt-host-validate
QEMU: Checking for hardware virtualization : PASS
QEMU: Checking if device /dev/kvm exists : PASS
QEMU: Checking if device /dev/kvm is accessible : PASS
QEMU: Checking if device /dev/vhost-net exists : PASS
QEMU: Checking if device /dev/net/tun exists : PASS
QEMU: Checking for cgroup 'memory' controller support : PASS
QEMU: Checking for cgroup 'memory' controller mount-point : PASS
QEMU: Checking for cgroup 'cpu' controller support : PASS
QEMU: Checking for cgroup 'cpu' controller mount-point : PASS
QEMU: Checking for cgroup 'cpuacct' controller support : PASS
QEMU: Checking for cgroup 'cpuacct' controller mount-point : PASS
QEMU: Checking for cgroup 'cpuset' controller support : PASS
QEMU: Checking for cgroup 'cpuset' controller mount-point : PASS
QEMU: Checking for cgroup 'devices' controller support : PASS
QEMU: Checking for cgroup 'devices' controller mount-point : PASS
QEMU: Checking for cgroup 'blkio' controller support : PASS
QEMU: Checking for cgroup 'blkio' controller mount-point : PASS
QEMU: Checking for device assignment IOMMU support : PASS
QEMU: Checking if IOMMU is enabled by kernel : PASS

Here, as you can see; We installed KVM and QEMU hypervisors on CentOS 8 successfully.

5. Instead of using KVM command-line tools, you can use the CentOS 8 native web interface, Cockpit, to manage machines and the virtualization environments through a graphical interface for a simpler and easier virtualization experience;

Use the below command to install Cockpit Web Console on CentOS 8:

dnf install -y cockpit

If you have the same output; Indicates that the installation of the cockpit web interface is complete.

6. At the next step; We are going to install the cockpit-machines package, It will need to add support of managing virtual machines;

We can use the below command:

dnf install -y cockpit-machines

Nice, we can see that the installation of the cockpit-machines package is completed successfully; We are so close to the end…

— We just need to enable and start Cockpit Unit to login to the Cockpit web Console;

The below command can help us:

systemctl enable --now cockpit.socket

Note: You can use the following address: IP-Server ADDRESS:9090 in your browser, to access your Cockpit web Console.

Note: Cockpit service is allowed by default in CentOS 8 firewall; Also you need to Ignore the Security warning that will pop up after using the address in the browser and continue to the Cockpit web Console login page.

As you can see in the image:

— Click on the advanced button and use the Proceed to 185.17.40.179 (unsafe) link, to login to the Cockpit web Console:

— OK, now like at the below image; In the web console login screen, we are going to enter the system username and password:

7. Final step: finally, we need to Go into the Virtual Machines section of the Cockpit web Console from the left side of the Cockpit Web UI panel, to manage our KVM Virtual Machines;

As you can see in the below image:

Summary

You now learn that how to install and create KVM virtualization on Centos 8 using the Cockpit web Console; Also, get acquainted with the special features of KVM Hypervisor.

If you encounter an error during installation, or have questions about KVM virtualization, or have any comments on this article, even have experience using KVM, you can contact us in the comments section below.