If you have a Nutanix cluster on VMware vSphere which has been through some hypervisor upgrades, your CVM’s virtual hardware version may be a bit out of date.
The main requirement from the Nutanix perspective is that CVM virtual hardware versions should be the same across the AOS cluster, and this is checked by NCC. Still, since newer virtual hardware versions include security updates and sometimes feature updates or improvements from VMware you may want to bring this up to date.
If you have an AOS upgrade pending, completing that upgrade would be the easiest route to solution.
If you don’t have any AOS upgrade needed, please note Nutanix does not recommend manually updating the VM hardware version for CVMs. The recommended method is to allow virtual hardware version to update during an AOS upgrade.
Do be aware, if you manually updated the virtual hardware version to 13 or higher on ESXi 6.5 before Patch 4, or 6.7 before Update 3, this could cause the CVM to fail to boot. There is a known issue in ESXi which could disconnect the PCI Passthrough device(s) which provides the SSD’s and HDDs to the CVM, causing that the CVM will fail to boot until corrected. This is explained with solutions from VMware here:
https://kb.vmware.com/s/article/70668
One last thing, if you’re running AHV there’s really no step to update the virtual hardware version per-se. You just power-cycle the VM and it’s done. On an AHV cluster the CVMs manage the VM configuration and the AHV hosts don’t keep any persistent information about the VMs when they are powered off. Because of this architecture, the VM configuration and features, equivalent to virtual hardware version, are determined at power-on.