Install KVM from the CLI on Ubuntu 18.04

08 Jan 2020 - by 'Maurits van der Schee'

In a previous post I have installed OpenSSH (on Ubuntu 18.04) on my Dell R720xd. In this post I will show how to install KVM on it, so that you can start using it as a GNU/Linux hypervisor to run virtual machines. In this post I will also show how to load a graphical tool to connect to your KVM enabled server.

Install KVM

KVM requires CPU virtualization support (VT-x/AMD-V) to be enabled in the BIOS. You can check if your CPU is supported by installing cpu-checker and running the kvm-ok command.

sudo apt install cpu-checker -y
kvm-ok

This should show:

INFO: /dev/kvm exists
KVM acceleration can be used

If it does not then reboot, press F2 to enter the BIOS, enable the support and try again.

Now for the installation of the software

sudo apt-get install qemu-kvm libvirt-bin virtinst bridge-utils cpu-checker

You may also type groups and verify that you are member of the libvirt group. Before adding yourself log out and in to see if that adds you to the group. To test that the installation succeeded you can connect to the hypervisor by running:

virsh -c qemu:///system list

The output should be:

 Id    Name                           State
----------------------------------------------------

It is an empty list of virtual machines.

Now on your local computer (not on the server) install the virtual machine manager by running:

sudo apt install virt-manager

Now start virt-manager and create a new connection towards your server. This should use SSH.

NB: You can even run virt-manager on Windows 10 using the Windows Subsystem for Linux (WSL).

Create a VM

The command osinfo-query os gets you a list of supported operating systems. You may have to install this utility first with:

sudo apt install libosinfo-bin

To see what the os-variant values are for 3 longest supported Ubuntu versions, run:

osinfo-query --fields=short-id --sort=eol-date os vendor="Canonical Ltd" | tail -n 3

This outputs:

 ubuntu14.04         
 ubuntu16.04         
 ubuntu18.04

To add the image to /var/lib/libvirt/boot, run:

sudo wget http://nl.archive.ubuntu.com/ubuntu-cdimage-xubuntu/releases/18.04/release/xubuntu-18.04.3-desktop-amd64.iso -P /var/lib/libvirt/boot

You may use the virt-install command to install the latest Xubuntu on a 4 vCPU 8 GB RAM virtual machine, like this:

virt-install \
--name maurits-cloud \
--ram 8192 \
--disk path=/var/lib/libvirt/images/maurits-cloud.qcow2,size=256 \
--vcpus 4 \
--os-type linux \
--os-variant ubuntu18.04 \
--network network=default \
--graphics vnc \
--console pty,target_type=serial \
--cdrom /var/lib/libvirt/boot/xubuntu-18.04.3-desktop-amd64.iso

You can use the virtual machine manager to execute the (graphical) installation.

Next: KVM console access from the CLI

In the next post I will walk you through setting up serial console access from the KVM CLI to your virtual machines. This will allow you to quickly fix SSH connectivity issues in your VM or to enter a full disk encryption (LUKS) password. I will even explain how you can get access to the grub menu this way.

Click here to read the next article (on serial console access).

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TQ
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