Cells: keep some compute hosts empty in a child cell
Its really useful to keep some hosts empty in a child cell, so its easy to do upgrades using live-migrate, and leaves room for things like resizes.
The plan is to add this extra config:
CONF.cells.
Where you are able to select what percentage of hosts from the child cell, will not have their capacity reported to the parent cell.
The hosts with the most free memory are considered to by "empty", or at least the "most empty" so are selected first, before reserving any hosts that might not be completely empty.
It is still up to the child cells scheduler to be correctly stacking (rather than spreading) to ensure the hosts remain empty.
Blueprint information
- Status:
- Not started
- Approver:
- None
- Priority:
- Undefined
- Drafter:
- John Garbutt
- Direction:
- Needs approval
- Assignee:
- John Garbutt
- Definition:
- Drafting
- Series goal:
- None
- Implementation:
-
Unknown
- Milestone target:
- None
- Started by
- Completed by
Related branches
Related bugs
Sprints
Whiteboard
Since this is basically like a scheduler filter, this doesn't really need a spec, but I don't want to self-approve the blueprint either. --johnthetubaguy 28th October 2014
Gerrit topic: https:/
Addressed by: https:/
cells: adds CONF.cells.
