MS Cluster on 2 ESXi hosts

[Almero]

HI Guys , My client is asking if we can have a MS cluster across two ESXi hosts with physical RDMs. I have implemented this on many other sites , the catch being this one only has two ESXi hosts .

Considering its cluster across box , with a KB driven compulsory DR ANTI rule required , would it be possible to ever patch ESXi ? Would it be "supported/possible" to disable the DRS anti rule , power down one of the MS cluster VMS , and vmotion it to the ESXi host carrying VM 2 ? Pretty sure this requires 3 ESXi hosts to safely implement , but none of the KBs officially state that as a requirement .

So ESX1 running MSCLUSTERVM1

ESX2 Running MSCLUSTERVM2

Would we fail MS cluster over to MSCLUSTERVM2 , and Shut down MSCLUSTERVM1 .

Move MSCLUSTERVM1  to ESX2 and Patch and reboot ESX1

It does not sound like a good plan , but will it work / supported ?

[SupreetK]

It is okay but, only during the upgrade duration and hope nothing happens to ESXi-2 in the meantime. Also, there is no need to move VM-1 to ESXi-2. It can stay on ESXi-1 in powered off state. In that case, you don't have to disable the anti-affinity rule.

Please consider marking this answer as "correct" or "helpful" if you think your questions have been answered.

Cheers,

Supreet

[Almero · Accepted solution]

HI , SK , thanks for the input , I was specifically concerned about when i need to do maintenance / patch one of the ESXi hosts.

I have gone and tested this on another client , and it does NOT allow you to move VM1 to the same ESX2 where VM2 runs , even if VM1 is powered down . ( DR ANTI disabled )

This client will just have to buy one more ESXi host to make this a sustainable solution .

Error while trying to cold vmotion to the ESXi2

[SupreetK]

You don't have to move the VM to another host in the first place. In case you want to do maintenance on ESXi-1, VM-1 can stay on ESXi-1 in powered off state. Similarly, VM-2 can stay powered off on ESXi-2 during the maintenance. You do not have to do anything apart from powering off the VMs. Needless to say, more the no. of hosts higher are the availability options

Cheers,

Supreet

[Almero]

Ok , but to for example Patch ESX1 , i need to enter Maintenance mode .

I cannot do that while powered down VM1 on it .

[SupreetK]

You can. While entering the maintenance mode, do not select the option 'Move powered off VMs'.

Cheers,

Supreet