Live or online migration

This is where the migration gets interesting, and it is one of the most useful features of virtualization.

Before we start the process, let's go a little deeper to understand what happens under the hood. When we do a live migration, we are moving a live VM while users are accessing it. This means that the users shouldn't feel any disruption in VM availability when you do a live migration.

Live migration is a five stage, complex process, even though none of these processes are exposed to the sysadmins. libvirt will do the necessary work once the VM migration action is issued. The stages through which a VM migration goes are explained in the following:

• Stage 1: Preparing the destination

  When you initiate live migration, the source libvirt (SLibvirt) will contact the destination libvirt (DLibvirt) with the details of VM, which is going to be transferred live. DLibvirt will pass this information to the underlying QEMU with relevant options to enable live migration. QEMU...