When DRS maintenance mode is invoked, DRS is used to evacuate all virtual machines from one host to another, without incurring any downtime. This is specially useful for performing maintenance, updating an ESXi host, installing additional memory, or upgrading firmware, and so on.

In order to use maintenance mode in the vSphere architecture, a cluster needs to be created and DRS must be enabled. We have already covered how to create a cluster and enable DRS on the cluster in previous chapters. Once the cluster is created with DRS enabled, add the desired hosts to the cluster.

Once we have the hosts added to the cluster, select the host that needs to go in the maintenance mode. Click Actions | Enter Maintenance mode. As soon as the administrator confirms the activation of maintenance mode, the virtual machines from this host will be moved using vMotion to other hosts on the same cluster without any downtime. This screenshots demonstrates how to enter maintenance mode for a particular...