[pve-devel] adding a vm workload scheduler feature

[Thomas Lamprecht]

Am 17.11.2015 um 14:56 schrieb Martin Waschbüsch:
>> Am 17.11.2015 um 14:20 schrieb Alexandre DERUMIER <aderumier at odiso.com>:
>>
>>>> Unless all cluster nodes have identical hardware, how do you determine if a given node is a suitable target for a vm?
>> I think we could add a manual "host cpu weight" option, because it's difficult to compare cpus performance. (frequencies/nb cores/intel|amd).
Manual weighting VMs and (maybe also) Nodes would general be an good 
option (which Dietmar proposed once to me as an idea) shift the control 
more to the admin, which is normally better able to determine how the 
load should be spread, as there are also different use cases.

> Good point. Though, I was more thinking about situations where the cpu-type is not set to default (kvm64, I think?) but to something like 'IvyBridge' or Opteron_G5. (The primary use I had for using non-default cpu types was to expose features such as AES-NI to a vm.)
>
> Another thing that just occurred to me: Backup schedules and settings are not necessarily the same for each node, which means auto-migration could lead to double, or (worse!) no backup for a vm that was moved around?
>
> Dunno if these are just corner cases?

Configuration like done in the HA-Manager could be used, so that certain 
nodes are in a group and the VM is bound to this group, we could in fact 
use the group API from the HA-Manager.
Also migrations could be blocked when a service is doing stuff like a 
online backup.