How to optimize the virtual machine load after performing maintenance on a RHEV environment

Issue

• After performing maintenance, how do I rebalance the load on my hosts in a cluster?
• When I'm done performing maintenance on my RHEV cluster, some of the hosts end up with a ton of VMs and then you have a few hosts without many at all. I would like to be able to click a single button to balance the load instead of having to select a few VMs at a time and migrate manually.
• We would like to see the following happen : When a host returns from maintenance mode and re-activated, VMs running on other hosts auto-migrate and load balance, re-integrating the host that has just returned. At this point, after a patching cycle, I am stuck re-balancing the hosts manually.