Rebooting dilemmas after an update

After any update or upgrade, all administrators face the question of whether or not the node should be rebooted and whether or not virtual machines need to be power-cycled. A Proxmox upgrade process is usually very informative, letting us know whether the node really needs a reboot. Most updates do not require any reboot. They are simply package updates. However, some upgrades, such as kernel releases, newer grubs, and others, will require a node reboot to apply the new changes. The exact method of rebooting depends on each environment and the number and nature of the VMs that are stored per node. In this section, we are going to look at the most widely used method, which is by no means the only method.

How to do it…

For a minimal virtual machine downtime, we can live-migrate all the VMs from one node to another, then migrate them back to the original node. As of Proxmox VE 3.4, there is a nice GUI feature addition to instruct all VM migrations with a menu...