Virtualization 101 : oVirt, KVM, QEMU

In production environment, we usually deal with a big number of hypervisors - KVMs for example -, virtual machines, network, storage, ...

To be able to manage all that, we need a centralized system to manage the KVMs.

For that purpose, we use oVirt
OVirt is a management tool for KVMs that uses the libvirt library for its administrative tasks.

We could use an oVirt web-based console for our administrative tasks.
OVirt is made up of an engine and different agents that are used to communicate with the hosts.

We could use oVirt to manage our virtual machines, move them, manage their networks,...


The oVirt agents live on the different hosts where the virtual machines are running.

Vdsm is an example of agents that oVirt relies on for its communication with the KVM hosts.

KVM is a Linux a module, QEMU follows the same modular scheme as the Linux kernel.
The libvirt tool is built on top of QEMU to help us manage the virtual machines, their network, ..., using the virsh command.

QEMU virtualizes hardware - CPU for example - so it could be used by virtual machines.

After installing all the QEMU-libvirt components, we can check if our machine is ready to host virtual machines using the below command:

Example: - VM installation - :

We could use the command line to install a virtual machine as below:

Below is a short description of the different parameters the "virt-install" command uses:
  • --graphics vnc : we should be presented with a VNC console window to follow along with the installation procedure.
  • --network : parameter is related to our default virtual bridge.
  • --cdrom : refers to the ISO file for the VM installation.
  • --os-variant : set the guest for a specific OS - debian11, fedora35,win7, ... -
  • --network=default : with the default mode, only a single network interface is be created in the guest
  • --disk size : specifies the size of the storage for the virtual machine.
  • --graphics : tells us of the method by which the display of the host can be accessed, in our case, we will be presented with a VNC console window to access the VM.


Leave as a comment: