Upgrading to 5.0.2 and CentOS7, best practice advice

We have a working installation using CentOS 6.7 and OpenNebula 4.14.2.
Since CentOS 6 in not supported in OpenNebula 5 we need to upgrade the OS (reinstall) on everything.

We have a two node front-end+node / node setup with a shared GFS2 filsystem and Open vSwitch setup.
How would you advice to proceed doing this with a minimum of downtime and hassle.
We have some extra hardware that could be setup a CentOS 7 / OpenNebula 5 front-end / host and act as the starting point of a new system that we also could connect to the current datastore (GFS2 shared filesystem).
And as we evacuate the CentOS 6 machines they can be reinstalled with CentOS 7 and OpenNebula 5 and join as hosts in the new system.
I guess there is no clever way of doing this live?
Am i missing some option that OpenNebula 5 offers us in this scenario?
Thank you for any advice,

You can have CentOS 7 + OpenNebula 5 as frontend and CentOS 6 nodes. I believe that node packages can be installed in CentOS 6. If that is not the case unpack them and add the new files. Move the database to the new machine with CentOS 7 and start the upgrade. You can also add nodes with CentOS 7 and start moving the VMs from C6 nodes to C7.

To move VMs I think migrate/livemigrate will work but to be on the safe side I would undeploy/resume them:

  • Disable C6 hosts
  • Undeploy VM
  • Resume VM