Scheduling pods using a scheduler profile

You can use a scheduling profile to configure how the scheduler spreads pods across nodes to enforce low or high node utilization.

About scheduler profiles

You can use scheduler profiles to determine how the cluster distributes pods across nodes based on node resource utilization.

The following scheduler profiles are available:

LowNodeUtilization

This profile attempts to spread pods evenly across nodes to get low resource usage per node. This profile provides the default scheduler behavior.

HighNodeUtilization

This profile attempts to place as many pods as possible on to as few nodes as possible. This minimizes node count and has high resource usage per node.

note

Switching to the HighNodeUtilization scheduler profile will result in all pods of a ReplicaSet object being scheduled on the same node. This will add an increased risk for pod failure if the node fails.

NoScoring

This is a low-latency profile that strives for the quickest scheduling cycle by disabling all score plugins. This might sacrifice better scheduling decisions for faster ones.

Configure a scheduler profile

To customize how the cluster distributes pods across your nodes based on resource use, you can configure a specific scheduler profile.

Prerequisites

• Access to the cluster as a user with the cluster-admin role.

Procedure

1. Edit the Scheduler object:

   $ oc edit scheduler cluster

2. Specify the profile to use in the spec.profile field:

   apiVersion: config.openshift.io/v1
   kind: Scheduler
   metadata:
     name: cluster
   #...
   spec:
     mastersSchedulable: false
     profile: HighNodeUtilization
   #...

   Set spec.profile to LowNodeUtilization, HighNodeUtilization, or NoScoring.

3. Save the file to apply the changes.