You can't put the only existing host in maintenance since Hosted Engine is running on it and it can't migrateOr should I simply- shutdown the VMs in my Datacenter- shutdown engine VM- stop vdsmd on host- update host to both CentOS 7.2 and oVirt 3.6.1 packages with:# yum update- reboot host- verify vdsmd is ok- exit the global maintenance mode and wait for a few minutes the engine VM should on this fresh upgraded host- hopefully the host will come up again as active and I can start my VMs?- shutdown the VMs in your Datacenter- move the host to local maintenance- shutdown engine VM- yum update- reboot- exit maintenance