In the event of host OS changes or kernel or driver version upgrades, all clustered nodes must be restarted, which will cause business service interruption. With live migration technology, rolling active upgrades can significantly minimize the impacts on the services.

The rolling upgrade's functionality is migrating the VMs running on a node that needs to be upgraded to other nodes or clusters through live migration before restarting the node or cluster so that business services will not be interrupted. A rolling upgrade will not affect the business services, except that the live migration of VMs during the upgrade can cause business service fluctuations for about 1 second, and the overall upgrade process can be arranged.

The rolling upgrade will migrate production VMs running on nodes that need to be upgraded to other nodes in the same cluster and then migrate them back after the upgrade is complete and the upgraded nodes are restarted. The cluster to be upgraded must have sufficient resources.