After an update, all administrators face the question of whether the node should be rebooted or not. The Proxmox upgrade process is usually very informative and tells us whether the node really needs a reboot. Most of the updates do not require any reboot. They are simply packaged updates. But some upgrades, such as kernel releases, newer grubs, and security patches, will require a node reboot every time. The exact method of rebooting depends on the environment, number, and nature of the VMs stored per node. In this section, we will see the most widely used method, which is by no means the only method.
For minimal virtual machine downtime, we can live-migrate all the VMs from a node to a different node, and then migrate them back to the original node. As of Proxmox VE 5.0, there is a nice GUI feature addition to instruct all VM migrations with a menu instead of selecting and migrating one VM at a time. The feature is under the Bulk Actions drop-down...