vCLS VMs

[DaveSC69]

Hi,

I need to shutdown all my VM's and put the hosts in maintenance mode,

When I log into the vCenter ESXi on the host, each host has a VM whose name starts with "vCLS-" followed by a long alphanumeric code.  Would I need to shut that down, and if so, how do we power on this "vCLS-" VM?

Many thanks.

Dave

[pmichelli]

These are self managed by vCenter. They will power on automatically once your hosts and vCenter come back online.

If you are not shutting them all down at once, don't worry about a thing, put host in maintenance mode and it knows what to do with the LCM VMs. 

If you have to shut all hosts down at the same time, you can manually power off the remaining LCM machines on the last host, then bring it offline

[DaveSC69]

Hi, thanks for the response. I need to power down all VMs and put the hosts in maintenance mode so that I can upgrade the disks firmware on the SAN. So, will it still be OK for the vCLS to be powered on during this disks upgrade process?

If I do need to manually power off the vCLS VMs then can I just simply shut them down from vCenter? I don't have any usernames or passwords to them.

[pmichelli]

You can leave them running if you want during the disk upgrade if you are not powering off the hosts themselves. Worst case if something happens to them, vCenter will re-deploy new ones.

There is no username of password (or even a network interface). They are completely managed by vCenter. You can safely power them down if necessary. You may see warnings in vCenter about DRS and cluster health being degraded but that is totally normal. These will go away once the VMs are booted back up

Their entire purpose is to maintain DRS and cluster health. 

Your SAN vendor is only being cautious as there should not be any I/O to the disks when firmware is being applied in case something gets corrupted. I wouldn't even worry about the LCM ones. As I mentioned , worst case vCenter will deploy new ones.

Absolute worst case if they don't. Disable DRS and HA and re-enable. it will force vCenter to re-deploy the VMs

[DaveSC69]

Excellent, many thanks for your help.

[pmichelli]

You're very welcome. I hope everything goes smooth for you. If you run into any issues, just post back.

[markey165]

@DaveSC69 - A few things regarding vCLS:

1. You cannot simply power off vCLS VMs. The vCLS monitoring service will power them back on after 30 seconds if you try to shut them down.

2. vCLS VMs can be migrated to other hosts until there is only one host left. If that host is also put into Maintenance mode the vCLS VMs will be automatically powered off. Or if you shut it down manually and put the host into Maintenance Mode, it won't power back on

3. If you want to remove vCLS from the equation altogether, you can enable Retreat Mode (see link below). This is reserved for very specific use cases (such as infrastructure maintenance). It will disable vCLS , and remove all vCLS VMs from the cluster. Bear in mind this will also disable DRS, but if you are shutting down all VMs anyway that wouldn't be an issue. When you disable Retreat Mode after the maintenance has completed, it will recreate the vCLS VMs automatically.  In all honesty, you should be fine with option 2 though, i'm just mentioning Retreat Mode as another option for the sake of completeness. 

4. You mentioned not having the vCLS password, see last link below to answer that question

- vCLS during Infrastructure Maintenance

- Putting a Cluster in Retreat Mode

- Retreiving Password for vCLS VMs

HTH 😊

[DaveSC69]

Hi,

Thanks. We are not looking to shutdown the three Hosts, simply put them in maintenance mode whilst firmware on the SAN is upgraded. We will only power off all the VM's prior to maintenance mode.

Dave.

[markey165]

Hi @DaveSC69 

Yes my reply covers exactly that! I've only mentioned powering off vCLS VMs not hosts. 

Just sharing some additional info on vCLS specifically, on the points you mentioned about powering them off and passwords etc  👍😊

[battybishop]

putting host into maintenance mode will move vcls VM's to other hosts in cluster, you don't need to do anyhing.

[markey165]

Except ALL hosts are being put into maintenance mode Rob. Extra bit needed to clarify that putting the last host into maintenance mode will automatically power the vCLS VM(s) off. Removing it from maintenance mode will power it back on in ~30 seconds or so. But ultimately yes, shouldn't need to do anything beyond that. 

[battybishop]

OK, I can confirm that they will shutdown when the last once goes into maintenance mode. I've done this before for a planned power down without any issues.