vCenter and ESXi host maintenance

[FingerJC]

I recently stood up a new Horizon v8 2206 environment.  Before jumping into updating vCenter, I want to confirm what behavior I should expect.  I'm currently on vCenter v7 U3d and have delayed updating due to not understanding all the interactions between Horizon and vCenter. 

I am working off the assumption that while vCenter is down, existing Horizon sessions will persist, but instant clone provisioning is not going to be available.  I configured my instant clone pools to have 1 spare VDI.  This works well for the workload this environment is doing.  Do I temporarily bump up the number of spare desktops prior taking vCenter down?  Or will vCenter work cause other login issues for new sessions?

Up to this point, I have been putting hosts in maintenance, patching/restarting/etc without issue.  I just stumbled on this article this morning, indicating I should be disabling Instant Clone ParentVMs.  I'm not sure what the purpose of this is.  I have 3 hosts in this cluster and I haven't encountered issues with my instant clone desktop pools when I work on hosts.

https://docs.vmware.com/en/VMware-Horizon/2206/virtual-desktops/GUID-7C5BB17B-D239-4779-B2CA-B9AD9C7...

Thanks,
Joel

[tdoc210 · Accepted solution]

Hi,

So from my experience, you will only be able to access  VDI vm's that have already been provisioned.  Increasing your spare count could help in this situation. 

My experience was during an outage, when the vcenter binding account got locked out, no VM's could be provisioned but the existing VM's could be accessed via the connection server

[Jubish-Jose]

The reason for disabling provisions during vCenter upgrade is to avoid new VM provisioning because that will cause errors since vCenter is down. You should be able to use the existing VMs as long as the ESX hosts are up and running the VMs.

[FingerJC]

Thanks for the replies!  So, the process would be, increase the spare count to best guess estimate of actual usage, disable provisioning (is this to be done at the desktop pool level or go to Servers / vCenter Servers and disable provisioning?), perform maintenance on vCenter, reenable provisioning and set my spare count back to 1. 

What exactly is Disable ParentVMs and what is the use case for that?

Thanks,
Joel

[Jubish-Jose]

I don't expect the vCenter upgrade to take a long time, but if you prefer, choose a time outside core business hours. Disable provisioning in desktop pool level. 

Where do you see the option to disable parent VMs? Which version of Horizon?

[FingerJC]

Horizon 8 (AKA 2206) Settings / Servers / vCenter Servers.  From the More drop menu, there is an option to Disable Provisioning and Disable ParentVMs.

Thank,
Joel

[Jubish-Jose]

Ok, got it. This is for maintaining the hosts, not vCenter. 

https://docs.vmware.com/en/VMware-Horizon/2209/virtual-desktops/GUID-7C5BB17B-D239-4779-B2CA-B9AD9C7...