In order to allow MAAS to be able to boot KVM virtual machines (via libvirt), these are the steps that one has to follow. They are intended for a Ubuntu system, but you can easily figure out how to make them work on Fedora or CentOS:

$ sudo apt-get install libvirt-bin

When adding nodes to MAAS that run as KVM virtual machines, the node configuration in MAAS will have to be updated to properly reflect the power type. In this case, the power type will be virsh. The virsh power type requires two fields: the “address” and the “power ID”. The “address” is just a libvirt URL. For example, qemu:///system for accessing libvirt on the local host, or qemu+ssh://root@hostname/system to access libvirt as root over SSH. The “power ID” field is just the virtual machine name or identifier.

In order to use SSH to access libvirt from MAAS, an SSH private key will have to be generated, and the public key uploaded to the host where the libvirt server is running:

$ sudo mkdir -p /home/maas
sudo chown maas:maas /home/maas
sudo chsh -s /bin/bash maas
sudo -u maas ssh-keygen
Generating public/private rsa key pair.
Enter file in which to save the key (/home/maas/.ssh/id_rsa): 
Created directory '/home/maas/.ssh'.
Enter passphrase (empty for no passphrase): 
Enter same passphrase again: 
Your identification has been saved in /home/maas/.ssh/id_rsa.
Your public key has been saved in /home/maas/.ssh/id_rsa.pub.

Finally, add the public key to /root/.ssh/authorized_keys2 where the libvirt server is running, so that virsh can SSH into it without a password:

$ sudo -u maas ssh-copy-id root@hostname

Finally, as the maas user, test the connection:

$ sudo -u maas virsh -c qemu+ssh://root@hostname/system list -all