The OpenNebula controller node does periodic polling of the configured VM hosts.
If your OpenNebula controller can't connect to a system you'll see output like this:
that is to be monitored you'll see the following errors in your /var/log/one/oned.log
The information drivers are transport mechanisms that are set in your ONE config file at /etc/one/oned.conf. While at it, you can also reduce the polling interval, that is 600 seconds per default. OpenNebula only transfers very little data anyway!
You have to enable all that you want to configure in your onehost create command.
Afterwards you must restart your ONE daemons.
If you also run into the following error, that is a quite funny one:
I was not booting into Xen by default...
After rebooting into Xen and waiting one polling interval you should see OpenNebula has updated the performance info:
libvirt / KVM socket permissions
OpenNebula oneadmin user needs to be in libvirt-bin group on your Ubuntu KVM boxes, otherwise there will be permission denied error on accessing the libvirt socket.
On Debian, the oneadmin user has a incorrect sudoers entry and he's not in the right group in /etc.
Of course, there is a Debian bug for this. Of course, it's still not ok. I love the Debian way.