Open Stack

On 02/12/2015 10:10 AM, Chris Friesen wrote:
> On 02/12/2015 03:44 AM, Sylvain Bauza wrote:
>
>> Any action done by the operator is always more important than what the
>> Scheduler
>> could decide. So, in an emergency situation, the operator wants to
>> force a
>> migration to an host, we need to accept it and do it, even if it
>> doesn't match
>> what the Scheduler could decide (and could violate any policy)
>>
>> That's a *force* action, so please leave the operator decide.
>
> Are we suggesting that the operator would/should only ever specify a
> specific host if the situation is an emergency?
>
> If not, then perhaps it would make sense to have it go through the
> scheduler filters even if a host is specified.  We could then have a
> "--force" flag that would proceed anyways even if the filters don't match.
>
> There are some cases (provider networks or PCI passthrough for example)
> where it really makes no sense to try and run an instance on a compute
> node that wouldn't pass the scheduler filters.  Maybe it would make the
> most sense to specify a list of which filters to override while still
> using the others.

FWIW, I completely agree with you, Chris. The force_hosts functionality 
is antithetical to cloud provisioning, (IMO it's a relic of managed 
hosting operations thinking) and should be removed from the Nova 
scheduler's "feature" list.

Best,
-jay