Watcher Overload standard deviation algorithm

Registered by Alexander Chadin on 2015-11-04

We find it necessary to check load of hosts in a cluster using overload algorithm that based on standard deviation. It is implemented as watcher's strategy. 2 properties might be checked:
CPU
RAM
The standard deviation strategy checks these properties of compute nodes every minute:
Computes the ratio between occupied resourses and total resourses for each compute node
Computes arithmetic mean of each property for all compute nodes
Calculates standard deviation of each property
Checks if any properties exceed the acceptable standard deviation and if they do, makes decision to migrate
The goal of this algorithm is minimizing the standard deviation.

Blueprint information

Status:
Complete
Approver:
Antoine Cabot
Priority:
Medium
Drafter:
Alexander Chadin
Direction:
Approved
Assignee:
Alexander Chadin
Definition:
Approved
Series goal:
Accepted for newton
Implementation:
Implemented
Milestone target:
milestone icon newton-1
Started by
Alexander Chadin on 2016-04-18
Completed by
Antoine Cabot on 2016-05-30

Related branches

Sprints

Whiteboard

Alex, any update on specs ?

Sorry for waiting, we have been too busy. We have been working on it since this January.

Gerrit topic: https://review.openstack.org/#q,topic:bp/watcher-overload-sd,n,z

Addressed by: https://review.openstack.org/286153
    Add Overload standard deviation strategy spec

Addressed by: https://review.openstack.org/297590
    Add Overload standard deviation strategy

(?)

Work Items

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