Guest VMs not automatically failing back over to failed host after it comes back on-line

[pbalderos]

Hello Community,

Hoping you all could help. I have a two host cluster that is HA enabled. Yesterday, one of the host failed and the guest VMs successfully migrated to the second host. Once the host came back on-line

the migrated VMs did not "return home" to the original host. I looked at the HA settings but do not see where that control is an option and that's why I assumed it should automatically happen. Could you all perhaps tell me what I am missing here?

Thanks in Advance!

[Alex_Romeo]

Hi,

Actually it is the DRS that takes care of load balancing between hosts. HA turns off and restarts the virtual machines in case someone is not working well.

This can be useful for you:

https://www.settlersoman.com/vcenter-is-down-impact-on-vmware-infrastructure/

ARomeo

[pbalderos]

Thank you! I will read up on that some more.

[pbalderos]

AlessandroRomeo68​

So, is it possible to configure DRS to move the affected VMs back "home"?

[cjscol · Accepted solution]

Use DRS Rules,

create a host group (create 2 groups and put one host in one group and the other host in the other group)

and a VM group (again create two groups, put all the VMs you want to run on host1 in one group and all the other VMs in the other group)

and then a "Run VMs on Hosts" DRS rule to set which VM group should run on each Host group. Again will need 2 rules, one per hosts.

[pbalderos]

cjscol​

Excellent! Thanks that's the other key piece that I was looking for.

[pbalderos]

cjscol​

One more question: If after I follow your recommendation, will HA still work if a host goes down from that cluster?

[IRIX201110141]

Depending on your vSphere ESXi version the answers from above are not a good adivce or at least incomplete. HA can take DRS into place which ends up that no VM is restartet because it can violate a DRS rule....  not what you want when speaking about HA

1. DRS means Enterprise Plus licensing. Is this what you have in your 2 Host cluster?

2. A "should" DRS Rule may will work together with HA and will migrate a VM backup but you have take a look to 3. as well

3. There are some adv. DAS rules for the HA configuration to tell ESXi how to deal with DRS in a HA event. These default have changed in the past and also the option within the GUI was revoked!

So use:

das.respectVmHostSoftAffinityRules = TRUE | FALSE

das.respectVmVmAntiAffinityRules = TRUE | FALSE

als well.

Regards,

Joerg