I noted a warning on my home lab VMware vSAN environment noting a missing critical patch with vSAN and deduplication environments. The patch was referencing the VMware KB article for all-flash clusters with deduplication enabled. This fit my environment in its current iteration. The host that was showing the missing patch was the VMware vSAN Witness host. Let’s take a look at how to update VMware vSANWitness appliance with needed patches.
Update VMware vSAN Witness Appliance
According to VMware documentation, they seem to support updating/upgrading VMware vSAN witness appliance hosts using the standard means of updating. See the VMware KB article here: https://kb.vmware.com/s/article/2143999. While this involves another issue, it indicates VMware supports upgrading the appliance using “your preferred method”.
To rewind back to the issue seen in the home lab environment, I had a warning there was a “patch available for critical vSAN issue for All-Flash clusters with deduplication enabled“.
Message that patch is available for critical vSAN issue for all-flash environments
The details of the missing patch reflect that it is missing on the VMware vSAN Witness host.
VMware vSAN Witness host was showing as needing the patch
To proceed with updating the VMware vSAN Witness host, I will place the host in maintenance mode. To do that, navigate to Cluster >> Configure >> vSAN >> Disk Management and select the host in question. After highlighting the host, using the maintenance mode icon to place it in maintenance mode.
Placing the VMware vSAN Witness host in maintenance mode
Here we confirm the action of placing the witness host in maintenance mode.
Confirm placing the VMware vSAN Witness host in maintenance mode
Now, we should see the vSAN Witness host in maintenance mode.
Verify the VMware vSAN Witness Host is now in maintenance mode
Using update manager, scanning the Witness host shows the needed missing patch.
Using update manager scan the VMware vSAN Witness host for updates
The missing patch shown is the ESXi650-201712401-BG package.
The needed patch has been staged for the vSAN Witness host
We begin the remediate process on the host.
Select baselines in update manager
Selecting the vSAN Witness host in the update manager wizard to apply the needed patch.
Select the target object which is the VMware vSAN Witness host
Select the update package(s) to apply to the vSAN Witness host.
Choose the patches and extensions for the vSAN Witness host
Choose any advanced options.
Choose any advanced options for the update
Select you host remediation options.
Configure host remediation options
Finalize the patch installation options.
Finalize the VMware vSAN Witness host update options
We can watch the update task in vCenter proceed as the patches are applied and the host is rebooted.
The update patch process begins on the vSAN Witness host
After the VMware vSAN Witness host comes back up, we no longer see the needed patch displaying as a warning in the vSAN Health Monitor.
No longer have the warning for the vSAN patch needed
Concluding Thoughts
The process to update VMware vSAN Witness host is fairly straightforward and generally follows the same regimen as updating a “regular” ESXi host. However, always make sure to follow the guidance of VMware if you are having a specific issue with vSAN or any other VMware product. The vSAN Health monitor is really nice in that it allows you to easily have a high-level overview of the health of the vSAN environment and quickly links you to relevant VMware KB articles with solutions. Making sure to resolve any issues that are found in the Health monitor will ensure you have a healthy and performant vSAN cluster.
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