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Tune the control plane

You can configure 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 API request rate limit

The rate limit controls how many API requests OKD Virtualization sends to the API server. Tune it when you create and maintain a large number of virtual machines (VMs) in one cluster, so that bulk operations are not throttled.

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"}}