Restrictions regarding vSAN clusters when changing the FQDN of a vCenter Server

Products

• VMware vSAN

Issue/Introduction

This article provides recommendations related to vSAN clusters when changing the FQDN of a vCenter Server.

Environment

VMware vSAN

Cause

When changing the vCenter Server FQDN, the vSAN unicast agent list may be impacted.

Resolution

To avoid the vSAN unicast agent list being impacted by the change, the recommendation is to deactivate cluster member updates from the vCenter Server by setting the parameter "IgnoreClusterMemberListUpdates" to 1 in all vSAN nodes before the FQDN change.

In other words, a value of 1 for "IgnoreClusterMemberListUpdates" tells the host to ignore any updates coming from vCenter regarding the unicast agent list.
While a value of 0, which is the default setting, tells the host to accept the changes coming from vCenter.

 

So the recommended order is:

1 - Set the parameter to 1 by running the following command in each vSAN node:

esxcfg-advcfg -s 1 /VSAN/IgnoreClusterMemberListUpdates

 

2 - Proceed with the vCenter Server FQDN change.

 

3 - Set the parameter "IgnoreClusterMemberListUpdates" to 0 again in all vSAN nodes to enable cluster member updates from vCenter again, by running the following command in each node:

esxcfg-advcfg -s 0 /VSAN/IgnoreClusterMemberListUpdates

Additional Information

• While the setting IgnoreClusterMemberListUpdates is configured to 1, Skyline Health will provide you with errors. Please ignore them until the whole procedure is over and this is configured to 0 again in all hosts.
• Although vSAN can run independently from vCenter, we do recommend having valid backups for the VMs in the vSAN clusters before performing the task.
• For more information on how to change vCenter Server's FQDN, you may refer to Changing your vCenter Server’s FQDN.