[openstack-dev] [nova] [placement] compute nodes use of placement

Chris Dent cdent+os at anticdent.org
Mon Jul 30 18:20:51 UTC 2018


On Mon, 30 Jul 2018, Jay Pipes wrote:

> On 07/26/2018 12:15 PM, Chris Dent wrote:
>> The `in_tree` calls happen from the report client method
>> `_get_providers_in_tree` which is called by
>> `_ensure_resource_provider` which can be called from multiple
>> places, but in this case is being called both times from
>> `get_provider_tree_and_ensure_root`, which is also responsible for
>> two of the inventory request.
>> 
>> `get_provider_tree_and_ensure_root` is called by `_update` in the
>> resource tracker.
>> 
>> `_update` is called by both `_init_compute_node` and
>> `_update_available_resource`. Every single period job iteration.
>> `_init_compute_node` is called from _update_available_resource`
>> itself.
>> 
>> That accounts for the overall doubling.
>
> Actually, no. What accounts for the overall doubling is the fact that we no 
> longer short-circuit return from _update() when there are no known changes in 
> the node's resources.

I think we're basically agreeing on this: I'm describing the current
state of affairs, not attempting to describe why it is that way.
Your insight helps to explain why.

I have a set of change in progress which experiments with what
happens if we don't call placement a second time in the _update
call:

   https://review.openstack.org/#/c/587050/

Just to see what might blow up.

-- 
Chris Dent                       ٩◔̯◔۶           https://anticdent.org/
freenode: cdent                                         tw: @anticdent


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