[nova][scheduler] - Stack VMs based on RAM
On 4/19/2019 4:38 PM, melanie witt wrote:
> I agree it sounds like your overcommit settings are not being honored.
> Placement will filter hosts taking overcommit into account, and if it
> doesn't have the values you set, then it will return more hosts than the
> RamFilter would filter, causing the difference in behavior.
> To debug this further, you need to start looking at what values
> placement has for the allocation ratios. You can do this by installing
> the osc-placement plugin  for the openstackclient. Once installed,
> you can do 'openstack resource provider inventory list <compute host
> UUID>' to see what allocation ratios are being used on a given compute
> host. If they're not 1.0, that would explain why it's returning too many
> hosts. If that's the case, next step would be trying to figure out why
> the values you're setting in nova.conf on the compute host (I assume you
> made sure to restart nova-compute after setting) are not being
> transferred to placement like they should be.
Some more background on how placement is involved here: