scheduler: Add instance number as weight when select hosts

Registered by jichenjc on 2014-10-13

Currently nova filter hosts by using given filters, then it will select
the 'best' match host by sorting the hosts with its weight. Currently
there are 2 weight object existing, one is metrics and the other is ram weight;
metrics weight is mostly for monitor so ram is the only one widely used.
If we have following scenarios: 1 host with 10G memory and already has
5 vms each has 1G virtual memory, another host has 2G memory without
any vm on it. Currently scheduler will select the first host because it
has more memory left but apparently it will increase the workload of the host
e.g. I/O rate etc.

Blueprint information

Status:
Started
Approver:
John Garbutt
Priority:
Low
Drafter:
jichenjc
Direction:
Needs approval
Assignee:
jichenjc
Definition:
Pending Approval
Series goal:
None
Implementation:
Needs Code Review
Milestone target:
None
Started by
John Garbutt on 2015-10-13

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Sprints

Whiteboard

Accepted into juno. Seems Ok, and this doesn't need a spec. --johnthetubaguy 13th October 2014

Gerrit topic: https://review.openstack.org/#q,topic:bp/add-instance-number-as-weight,n,z

Addressed by: https://review.openstack.org/130526
    Create Nova Scheduler Num Instances Weighter

Bumping to k-2 -- mikal 9 Dec 2014

Sorry, we have now hit the non-priority feature freeze for kilo. Please resubmit your spec for the L release. --johnthetubaguy 5th Feb 2015

Re-approving for liberty, doesn't need a spec --johnthetubaguy 13th April 2015

Re-approving for mitaka --johnthetubaguy 13th October 2015

Sorry, we have now hit the Non-Priority Feature Freeze for Mitaka. For more details please see: http://docs.openstack.org/releases/schedules/mitaka.html#m-nova-npff and http://docs.openstack.org/developer/nova/process.html#non-priority-feature-freeze
--johnthetubaguy 2016.01.30

(?)

Work Items

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