Unable to get the VM's register on the Stateless ESXi Servers after maintenance activity.

[Clament]

Current Environment

4 Host servers have configured as stateless ESX i 5.1 in a single datacenter cluster.

Management Servers (AD, SQL, vCenter servers) has been configured on different host as stat full ESXi on the local data store. As part of maintenance activity we have powered down all the VM's and Host servers.

ISSUE

After maintenance activity we have powered up the Management servers and Host stateless ESXi servers.

Now the Stateless ESXi servers has obtained IP address, different than which was before.

We could see 4 ESXi Host on the vCenter server as disconnected status with old IP address and registered VM's.

When we tried to add the 4 Stateless ESXi servers with new IP address, we couldn't see VM's.

What will be the root cause and solution for this issue?

Note: We don't have DNS configured for this environment.

[admin]

This happened because the hosts rebooted are stateless, and got a different identity (IP address). In order to get the VMs back, register them from the datastore into the inventory. If required unregister (remove from inventory) the hosts which are not communicating now.

It would be a good idea to have a static IP address assigned to these servers by binding IP addresses to the mac address of the stateless hosts in DHCP server configuration. I.e. let stateless host obtain IP from DHCP lease, but make DHCP server assign the same IP address everytime. Hope my explanation is clear.

[Clament]

Hi ,

Thanks for your prompt response .

We have around 300 + VM's running on the servers , it would take much time to get the VM's unregistered and get them registered to the data store again one by one . We are concerned that it should not get any VM's impacted.

I agree to your suggestion with respect to DHCP, going forward will have this planned and will take it up.

[admin]

Unregistering should be quite simple, when you remove 4 hosts from inventory it will remove the associated VMs too. This will not have any impact on the VMs. However, for registering VMs you could use below ESX command in a script:

vim-cmd solo/registervm <path to vm>

It would be good to register the VMs first to ESX hosts, then add the hosts to Virtual Center inventory, else it can cause mismatch in the inventory.

[Clament]

We were looking for options to get his done.

Its know that removing the hosts from the cluster and add it back would be simple and easy job.  Thing is that once again all those 300 + VM's would need to get either manually registered or through script is the concern.