KVM / QEMU

KVM and Qemu provide Virtual Machines on Linux. Lighter weight and easier to manage remotely than virtualbox.

KVM Installation and Deployment

Guide: https://help.ubuntu.com/community/KVM/Installation

sudo apt-get install qemu-kvm libvirt-daemon-system libvirt-clients bridge-utils

Add user to correct group:

Cosmic (18.10)

The group name is changed to libvirt:

sudo adduser `id -un` libvirt

Adding user <username> to group libvirt ...

After the installation, you need to relogin so that your user becomes an effective member of kvm and libvirtd user groups. The members of this group can run virtual machines.

Virsh

Verify everything works as expected by running:

virsh list --all

Virt-manager

Optional: Install virt-manager (graphical user interface)

If you are working on a desktop computer you might want to install a GUI tool to manage virtual machines.

sudo apt-get install virt-manager

To start and stop VMs:

virt-manager

Note: may need to log out and log back in (restart system)

or

newgrp libvirt

via: https://askubuntu.com/questions/345218/virt-manager-cant-connect-to-libvirt

Import Existing

QCOW images are expected to be in

/var/lib/libvirt/images

Then choose create new machine from existing by selecting qcow and specifying the OS.

Find IP in machine settings and then add a map in /etc/hosts

vm 192.168.122.25

Creating new machine

Under main virt-viewer window:

View -> Scale Display -> Always

Under main virt-manager, current machine settings ('i')

Video Virtio -> Video Model -> Virtio (set while machine is off?)

spice-vdagent copy-paste for qemu

For a list of osinfo strings to use with the --os-variant option:

sudo apt install libosinfo-bin
osinfo-query os

-s is the size, in GB, of the disk image:

sudo virt-install --connect qemu:///system -n xubuntu -r 2048 -f xubuntu.qcow2 -s 16 -c Downloads/xubuntu/xubuntu-18.04-desktop-amd64.iso --vnc --noautoconsole --os-type linux --os-variant ubuntu18.04 --accelerate --network=network:default

Connect to the new VM using virt-viewer:

virt-viewer -c qemu:///system xubuntu

To change the display size, just use the native OS settings to adjust the size. (No integration like VirtualBox Addons that changes the resolution dynamically when the window is resized)

Prerequisites / Troubleshooting

Make sure that your system has the hardware virtualization extensions: For Intel-based hosts, verify the CPU virtualization extension [vmx] are available using following command.

[root@server ~]# grep -e 'vmx' /proc/cpuinfo

For AMD-based hosts, verify the CPU virtualization extension [svm] are available.

[root@server ~]# grep -e 'svm' /proc/cpuinfo

If there is no output make sure that virtualization extensions is enabled in BIOS.

Verify that KVM modules are loaded in the kernel “it should be loaded by default”.

[root@server ~]# lsmod | grep kvm

The output should contains kvm_intel for intel-based hosts or kvm_amd for amd-based hosts.

See also

https://www.tecmint.com/install-and-configure-kvm-in-linux/