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Virtual machine control plane tuning

In OKD Virtualization, you can control how the control plane handles concurrency when you create or migrate virtual machines (VMs). For example, set the QPS or burst rates to batch create virtual machines (VMs) in a batch, or tune migration settings in the HyperConverged custom resource (CR).

Tune the rate limit

You can tune the rate limit when creating and maintaining a large number of virtual machines (VMs) in one cluster.

The hco.kubevirt.io/tuningPolicy annotation is used to configure the rate limit. The annotation is only taken into account if the annotation tuning policy is applied to the HyperConverged CR.

Prerequisites

  • You have installed the OpenShift CLI (oc).

Procedure

  1. Annotate the HyperConverged CR with the hco.kubevirt.io/tuningPolicy annotation, and a value of a json object with the following fields:

    • qps: indicates the maximum QPS to the apiserver from this client.

    • burst: Maximum burst for throttle.

      For example, to set the qps to 100 and the burst to 200, use the following command:

    $ oc annotate hco kubevirt-hyperconverged -n kubevirt-hyperconverged 'hco.kubevirt.io/tuningPolicy={"qps": 100, "burst": 200}'

  2. Apply the following patch to enable the annotation tuning policy:

    $ oc patch hco kubevirt-hyperconverged -n kubevirt-hyperconverged \
  --type=json -p='[{"op": "add", "path": "/spec/virtualization/tuningPolicy", \
  "value": "annotation"}]'
Verification

  • Run the following command to verify the rate limit tuning:

    $ oc get kubevirt.kubevirt.io/kubevirt-kubevirt-hyperconverged \
  -n kubevirt-hyperconverged -o go-template --template='{{range $config, \
  $value := .spec.configuration}} {{if eq $config "apiConfiguration" \
  "webhookConfiguration" "controllerConfiguration" "handlerConfiguration"}} \
  {{"\n"}} {{$config}} = {{$value}} {{end}} {{end}} {{"\n"}}