Issue with vmRolloutStrategy Configuration in KubeVirt Documentation

[laopoom]

Hello KubeVirt Team,

I'm reaching out to report a potential issue in the KubeVirt documentation and its implementation. According to the official KubeVirt documentation, starting from version 1.1, KubeVirt supports memory hot-plug. The documentation provides a configuration example for enabling this feature, which includes setting the vmRolloutStrategy under the KubeVirt resource.

The specified configuration is as follows:

apiVersion: kubevirt.io/v1
kind: KubeVirt
spec:
  configuration:
    vmRolloutStrategy: "LiveUpdate"

However, when attempting to apply this configuration in a practical environment using KubeVirt version 1.1.0-150500.8.6.1 with the following command:

kubectl --namespace kubevirt patch kv kubevirt -p='[{"op": "add", "path": "/spec/configuration/vmRolloutStrategy", "value": "LiveUpdate"}]' --type='json'

I encountered the following warning:

Warning: unknown field "spec.configuration.vmRolloutStrategy"
It seems that either the vmRolloutStrategy field is not recognized in this version, or there may be a discrepancy between the documentation and the actual implementation.

Could you please clarify the following:

1. Is the vmRolloutStrategy field supported in KubeVirt version 1.1 as stated in the documentation?

2. If it is supported, is there a different procedure or path that should be used for this configuration?

3. If it is not supported in this version, could the documentation be updated to reflect this, or could you suggest an alternative approach to achieve similar functionality?

Thank you for your attention to this matter and for your continuous efforts in improving KubeVirt.

[nepomucen]

I hit the same problem as you. The thing is, there is no user documentation available per specific Kubevirt version.
The memory/cpu hot-plug features are available in Kubevirt version used by you (1.1), but needs to be enabled differently, per VM spec., rather than cluster-wide, through CR: spec.configuration.vmRolloutStrategy, like this:

apiVersion: kubevirt.io/v1
kind: VirtualMachine
spec:
  liveUpdateFeatures:
    memory:
      maxGuest: 2Gi

Check for details this user-guide, valid for your Kubevirt version.
You can also consult API Reference 1.1.0, and see that "spec.configuration.vmRolloutStrategy" field is not implemented in v1.KubeVirtConfiguration

[fabiand]

cc @jean-edouard @acardace @xpivarc

Hot-plug was non-GA in 1.1 and there was indeed quite a redesign of hot-plug between 1.1 and 1.2.

In 1.1 the API was workload centric, while in 1.2 it got simplified, removed from the workload, and only cluster (KubeVirt CR) sided.

Please see kubevirt/community#242 for the most recent design.