Found another host participating in the vSAN service which is not a member of this host’s vCenter cluster

When reconfiguring my network environment (soon to be seen in the next HomeLab update) the vCenter gave an error message, which you have already read in the subject. In my case, it was about the vSAN Witness appliance.

Of course there is also a Knowledge Base article about this error message and the solution according to VMware is:

https://kb.vmware.com/s/article/2062704

To resolve this issue, check all ESXi host nodes in the vSAN cluster and ensure that their configuration is correct and all vSAN hosts are in the same network subnet.

No sooner said than done, I checked the configurations of each host as well as my virtual Witness Appliance and could not identify any differences. In Skyline Health there is an additional error message that the ping does not match the MTU size.

So now I come back to the beginning of this post, I changed my physical network configuration (how exactly I do not want to tell you yet, but very soon 😉 ), so I took a look at the switches and on one of the switches Jumbo Frames was not enabled. After activation I did another retesting in Skyline Health and lo and behold, the vSAN cluster is back in optimal state and the error messages are gone.

And that’s it from this post, if you have any questions please use the comment section below. 🙂