UberGeek1
Enthusiast
Enthusiast

So bypassing the argument about HA Admission Control, because I agree that when I loose a host it's fine, when I loos two hosts, then I would rather have swapping and ballooning than VMs hard down because they can't start.  When you have a cluster with 100+ hosts, having multiple host failures is a reality.

Anyway, if my understanding is correct, you don't need to have HA Admission Control actually enabled for vROps to read the settings, so changing the settings and leaving it disabled will allow vROps to use those numbers to perform it's calculations.  If you use capacity calculation based on actual available resources in the cluster, minus some buffer and your largest host, you probably want a PowerCLI script running nightly to automate this calculation and setting.  Of course, this is also based on my environment where a cluster of 100+ hosts will not always be the exact same, heck, most aren't even the same generation, but that's how it goes sometimes.

Either way, I've always found it arrogant that the typical answer from VMware is "You should be running HA Admission Control", and when I ask why, I basically get the "Because the cool kids do" type of answer, not an actual answer based in reality.  I do see some edge cases where it would be nice, but for most cases, good capacity planning and watching it is more key than trying to deploy a VM a customer requests only to find out you don't have capacity under HA Admission Control and now have to tell the user "Sorry, you're going to have to wait now".  I would rather do that up-front instead of after the fact.

Anyway, I relinquish the soap box...

Sincerely, Jody L. Whitlock
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