I recently encountered an issue , where the ESXi server on my 7 node cluster was disconnected , and all the VM under it were grayed out , but was still up and running,
No business impact nor the VM functionality was affected . but the ESXi hosts were disconnected form the cluster , and was no longer part of the HA a, DRS cluster ,
See the snippet below
Troubleshooting this , we performed these steps .
1.we Verified that the ESXi host is in a powered on state.
2. Verified that the ESXi host is able to respond back to vCenter Server at the correct IP address.
3.Verified that network connectivity exists from vCenter Server to the ESXi host with the IP and FQDN.
4. We did not restart the management network since the VM running under the ESXi host were grayed out and the state was unknown ,
restarting the management network can cause the VM to lose its files , and chances of corrupting the vmx .
5. verified the host connectivity by directly connecting to host using Vsphere client
6. Checked the network connectivity on the chassis on which these blades were mounted
7. analyzed the VM kernel logs , and the events and alarms for the UCS chassis
8. we figured out the FI had some port issues and Networking connectivity issue
9. we rectified It, removed the host form the Cluster , made sure we have the valid root credentials and added the host back to cluster
10. Do not reboot the host when the host and its vm state is unknown
11. Make sure you have the complete VM list and its host and network details before restarting the esxi host
Thanks and Regards,
Nithyanathan R