Cells specific to a flavor type

Registered by Mahesh Panchaksharaiah on 2013-11-18

In a cell setup there is currently no way to direct a build request to a specific cell.

There are cases where a new cell can be added with the required infrastructure to support certain flavor types. This feature would allow build requests to be directed to cells which support the requested flavor types.

This would be another use case of cells apart from scaling.

To implement this, support will be added for a new namespace of keys in flavor extra specs called "cells_extra_specs". These extra_specs will be compared with configured cells capabilities using a new cells scheduler filter.

Blueprint information

Status:
Started
Approver:
Russell Bryant
Priority:
Undefined
Drafter:
Mahesh Panchaksharaiah
Direction:
Needs approval
Assignee:
Mahesh Panchaksharaiah
Definition:
Review
Series goal:
None
Implementation:
Slow progress
Milestone target:
None
Started by
Mahesh Panchaksharaiah on 2014-01-03

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The cells filter scheduler already has a target cell filter, so there is a way to direct a build request to a specific cell. If that still doesn't support what you need, please add more detail around what filter you are proposing to be added. --russellb

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Hi Russell, this feature is similar to AggregateInstanceExtraSpecsFilter used with host aggregates to target builds for certain flavors to certain computes. In this case we will target certain cells to build certain flavors.

Ok, can you please add more detail on what filter you're proposing to add? What data does it act on? How does it match the request to certain cells? --russellb

The proposed feature involves directing build requests of a specific flavor category to cells which can handle it.
To achieve this, the flavor category will be added in instance_type extra_specs. The child cells will be configured to specify the flavor category it can support, this information will be populated to the parent cell as part of its capabilities. A cell scheduler filter will be added which would filter the cells based on the incoming request which will have the falvor category in the instance_type extra_specs. --maheshp

OK, I think this is headed in the right direction then. I'd like to see this as a generic filter for flavor extra specs and cell capabilities. I don't think it should be limited to a single category key. It should be all keys under a certain namespace, like "cells_extra_specs". The values should be compared to cell capabilities using the code in nova.scheduler.filters.extra_specs_ops. --russellb

    This blueprint has been deferred from the icehouse-3 milestone to Juno because it missed the "feature proposal freeze" deadline. https://wiki.openstack.org/wiki/Icehouse_Release_Schedule --russellb

Unapproved - please re-submit via nova-spec --johnthetubagy (20th March 2014)

Removed from next, as next is now reserved for near misses from the last milestone --johnthetubaguy

(?)

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