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How to Install and Use KVM libvirt on Ubuntu

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Virtualization Compatibility Check


Execute the below command to install the cpu-checker package.


apt install -y cpu-checker


check if your CPU supports virtualization by running this command.




If you get the following result, your CPU supports virtualization with KVM:


root@asus:~# kvm-ok
INFO: /dev/kvm exists
KVM acceleration can be used



Installing KVM on Ubuntu


Provided your CPU supports virtualization, you can install KVM on your machine.


To install KVM on Ubuntu, run the apt command below.


apt install qemu-kvm libvirt-clients libvirt-daemon-system bridge-utils virt-manager -y


These are the packages that will be installed:


qemu-kvm – This package provides accelerated KVM support. This is a userspace component for QEMU, responsible for accelerating KVM guest machines.


libvirt-daemon-system – This is the libvirt daemon and related management tools used for creating, managing, and destroying virtual machines on the host machine.


libvirt-clients – This provides the libvirt command-line interface for managing virtual machines.


bridge-utils – This package provides the userland tools used for configuring virtual network bridges. On a hosted virtualization system like KVM, the network bridge connects the virtual guest VM network with the real host machine network.


virt-manager – This provides a graphical user interface (GUI) for managing your virtual machines should you wish to use it.


If you want the libvirt daemon to start automatically at boot then enable libvirtd:


systemctl enable libvirtd


If libvirtd is not already running, do:


systemctl start libvirtd


Check if KVM is loaded in the kernel with:


lsmod | grep -i kvm




Overview of basic libvirt commands



To launch the libvirt KVM GUI Virtual Machine Manager run:





Alternatively you can use the virt-install commands to launch machines from the CLI.




virt-install –name fedora1 –vcpu 1 –memory 2048 –cdrom /root/Fedora-Workstation-Live-x86_64-36-1.5.iso –disk size=12 –check disk_size=off



This creates a Fedora machine with hostname fedora1 with 2GB RAM and a 12GB virtual hard drive.



To list all VMs:


virsh list –all


To shutdown the machine:



virsh shutdown fedora1



To start the machine:



virsh start fedora1



To display the storage allocated to the machine:



virsh domblklist fedora1


To destroy the machine:


virsh destroy fedora1


To delete the machine and its disk image use virsh undefine. This deletes the VM, and the –storage option takes the comma-separated list of storage you wish to remove. Example:


virsh undefine fedora1 -storage /var/lib/libvirt/images/fedora1-1.qcow2



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