After a planned power outage, an administrator decided to restart the vSAN cluster manually.

Run the Python reboot helper script only on one ESXi host to recover the cluster.

Enable cluster member updates from vCenter Server on all ESXi hosts.

Exit all hosts from maintenance mode.

During a manual vSAN cluster restart after a planned outage, the hosts must first be brought back and exited from maintenance mode so the cluster can begin recovery. The vSAN reboot helper recovery script must then be run on only one ESXi host. Running the script on multiple hosts can create race conditions and unexpected cluster state. After the recovery script completes, cluster member updates from vCenter Server must be enabled on all ESXi hosts so that normal membership updates resume across the cluster. Enabling updates on only one host is incomplete because all hosts must return to normal cluster-member update behavior. Running the Python reboot helper script on all ESXi hosts is explicitly incorrect because the recovery operation must be initiated from a single host only. Disabling cluster member updates is a shutdown-side activity, not the required restart-side recovery action in this question. Reference topics: Manual vSAN Cluster Restart, Reboot Helper Script, Maintenance Mode Exit, Cluster Member Updates.