4.9. Allocating specific CPUs for nodes in a cluster
When using the static CPU Manager policy, you can reserve specific CPUs for use by specific nodes in your cluster. For example, on a system with 24 CPUs, you could reserve CPUs numbered 0 - 3 for the control plane allowing the compute nodes to use CPUs 4 - 23.
4.9.1. Reserving CPUs for nodes
To explicitly define a list of CPUs that are reserved for specific nodes, create a KubeletConfig custom resource (CR) to define the reservedSystemCPUs parameter. This list supersedes the CPUs that might be reserved using the systemReserved and kubeReserved parameters.
Procedure
Obtain the label associated with the machine config pool (MCP) for the type of node you want to configure:
$ oc describe machineconfigpool <name>
For example:
$ oc describe machineconfigpool worker
Example output
Name: worker Namespace: Labels: machineconfiguration.openshift.io/mco-built-in= pools.operator.machineconfiguration.openshift.io/worker= 1 Annotations: <none> API Version: machineconfiguration.openshift.io/v1 Kind: MachineConfigPool ...- 1
- Get the MCP label.
Create a YAML file for the
KubeletConfigCR:apiVersion: machineconfiguration.openshift.io/v1 kind: KubeletConfig metadata: name: set-reserved-cpus 1 spec: kubeletConfig: reservedSystemCPUs: "0,1,2,3" 2 machineConfigPoolSelector: matchLabels: pools.operator.machineconfiguration.openshift.io/worker: "" 3
Create the CR object:
$ oc create -f <file_name>.yaml
Additional resources
-
For more information on the
systemReservedandkubeReservedparameters, see Allocating resources for nodes in an OpenShift Container Platform cluster.