HA - Insufficient resources to fail over this virtual machine.

[luca1994]

Hello Team,

i have this:

- 1 Instance vCenter 7.0.3

- 1 Cluster with 8 hosts ESXi 7.0.3

- HA Enable with admission control disable

Last weekend there was a problem with the power supply and four of the eight hosts belonging to the cluster went out.
Some vms were not moved and remained switched off. The error was "Insufficient resources to fail over this virtual machine. vSphere HA will retry the fail over when enough resources are available.Reason: Unable to find healthy compatible hosts for the VM".

Do you think this problem can be solved by configuring admission control?

Thank you very much for your support

[a_p_]

That's an interesting question. Some questions though.

1. Do the remaining 4 hosts have sufficient resources to run all VMs?
2. Do you use Resource Pool?
3. Do any of your VMs have CPU/RAM reservations configured?
4. Do you have DRS rules in place which may be related?

André

[luca1994]

Hi André,

following the response:

1. Do the remaining 4 hosts have sufficient resources to run all VMs? depends on what is meant by 'sufficient resources'.. four hosts should keep the vms running by overcommitting RAM and CPU
2. Do you use Resource Pool? No i don't use
3. Do any of your VMs have CPU/RAM reservations configured? No
4. Do you have DRS rules in place which may be related? No, DRS is only enable in Partially Autometed with vm automation enable.

Thanks for the support

Luca

 

[a_p_]

>>> ...  four hosts should keep the vms running by overcommitting RAM and CPU
Overcommitment may may indeed be a reason.

>>> Do you think this problem can be solved by configuring admission control?
It may not solve such an issue. However, what "Admission Control" will do, is to prevent VMs from being powered if HA cannot protect them, i.e. make you aware of a possible resource issue before disaster strikes.

André

[luca1994]

So the first step is to give more computational resources to the hosts or add more hosts to the cluster, correct?

Luca

[a_p_]

Basically yes, but it actually also depends on the current usage/requirements.
It may also be an option to check the current VM's provisioned CPU/RAM, i.e. whether this can be reduced without impact to the workloads.

André

[luca1994]

Thanks Andrè