vSphere Lifecycle Manager - Precheck - Parallel upgrades are not allowed between client and server clusters

Products

• VMware vSAN
• VMware Cloud Foundation

Issue/Introduction

• This article introduces the new vSAN Health check 'Parallel upgrades are not allowed between client and server clusters' in vSAN and provides details on why it might report the error and how to fix the error state.
• This check is used by remediation check of a vSAN cluster in vSphere Lifecycle Manager.

Environment

VMware vSAN 9.1

Resolution

Q: What does the 'Parallel upgrades are not allowed between client and server clusters' check do? 

• This health check is used to prevent parallel upgrades between vSAN server clusters and their vSAN client clusters.
• It ensures that a vSAN server cluster and its vSAN client clusters are not upgraded in parallel, and likewise prevents parallel upgrades between a vSAN client cluster and its vSAN server clusters.

Q: What does it mean when it is in an error state?

• If this test returns red, it means that during the upgrade of a vSAN server cluster, one of its vSAN client clusters is also being upgraded, or vice versa.

Q: How does one troubleshoot and fix the error state?

• Please retry remediation or remediation pre-check of this vSAN server cluster after the upgrade of its vSAN client clusters are compete, or vice versa.
• This parallel upgrade health check is enabled by default to avoid parallel upgrades between vSAN client and server clusters.
• Upgrading them in parallel may increase the risk of data unavailability.
• Make sure the risks of parallel upgrade are understood before skipping it.
• There is an option in "Advanced vCenter Server Settings" to specify whether to allow parallel upgrade of both vSAN client and server clusters in this vCenter:

1. 1. Go to "Setting"/"Advanced Settings" in Configure tab of this vCenter and you'll able to view the table of "Advanced vCenter Server Settings"
   2. By default, this option "config.vpxd.vsan.health.allowParallelUpgrade" is not there. To configure it, add it by "EDIT SETTINGS". To skip parallel upgrade health check, set the value as true.