Authors:

Tomer Saban

Feature pages are design documents that developers have created while collaborating on oVirt.

Most of them are outdated, but provide historical design context.

They are not user documentation and should not be treated as such.

Documentation is available here.

oVirt Scheduler Policies

Summary

This page describes the scheduler policies currently supported by oVirt. This scheduler controls scheduling in the cluster level. Last update: 03/30/2015.

Owner

Name: Tomer Saban (tsaban)

Getting Started with Scheduler Policies

This is the easiest explanation to active an internal scheduler policy.

Create scheduling policy

Enter the “Administrator portal”.
Click “configure”(At the top right edge of the screen). A dialog should open.
Click the tab “Scheduling policies” at the left side of the dialog.
Click “new” and create a new policy(Giving a name is enough in order to create A non-filtering policy).
Close the dialog.

Attach scheduling policy to a cluster

Click the “Clusters” tab.
Click a cluster to attach the policy to, from the table below(“Default” cluster is fine).
Click “edit”. A dialog should open.
Click “Scheduling Policy” on the left tab from the dialog.
In the “Select Policy” combo-box choose the name you gave the policy eariler.

Now the scheduling policy is attached to the cluster you choose and it’s working.

Current status of filter and weight policies

Policy	Kind	Status	Description
PinToHost	Filter	Working	Filters every host which the vm is not pinned to(Meaning the vm will migrate only to the host it is pinned to).
Migration	Filter	Working	Filters the host which the vm is currently resides on. Meaning, This policy encourages migrations.
CPU-Level	Filter	Working	Filters hosts by CPU level(manufacturer, model, etc).
CPU	Filter	Working	Filters hosts by CPU cores(Number of Virtual CPUs).
VmAffinityGroups	Filter	Working	Filters hosts by taking into consideration Affinity groups(positive affinity group means that all VMs should be on the same host and negative means that they should be on separated hosts).
Emulated-Machine	Filter	Working	Filters hosts by emulated machine(isapc, pc, etc).
Network	Filter	Working	Filters hosts who doesn’t have the necessary network interfaces to run the vm.
None	Filter	Working	No host is being filtered(The vm will migrate to the first available host).
None	Weight	Using even distribution policy instead.	Hosts receives score based on even distribution weight policy.
OptimalForEvenGuestDistribution	Weight	Working	Sets host scores based on the number of VMs on each host.
OptimalForEvenDistribution	Weight	Working	Sets hosts scores so that there will be even CPU usage distribution.
VmAffinityGroups	Weight	Working	Sets host scores based on affinity group (Hosts which are at the same affinity group as the vm and their affinity is positive or has different affinity group and their affinity is negative gets a specified score, bigger than 1 and the other gets a score of 1.
OptimalForHaReservation	Weight	Working	Sets scores for hosts according to the number of highly available vms on them and a scale down parameter.
OptimalForPowerSaving	Weight	Working	Sets host scores so that minimum number of hosts will need to stay on. Has influence only when used with hosted engine.
HA	Weight	Working	Weight are being set by the number of HA VMs on the host and a scale down parameter. Has influence only when used with hosted engine.
HA	Filter	Working	Filters hosts whose high availability score is negative(See ovirt-ha-agent for more details on how this score is calculated). Has influence only when used with hosted engine.
Memory	Filter	N/A	Filters hosts based on memory usage.