The current UI code is using descheduler.alpha.kubernetes.io/evict annotation to opt-in selected VMs to the the descheduler.

Having CNV descheduler integration reaching GA, we want to have all the live-migratable  VMs in by default and let the cluster admin eventually opt-out selected VMs.

descheduler.alpha.kubernetes.io/prefer-no-eviction annotation can be used to let the VM owner opt-out selected VMs: a VM annotated with descheduler.alpha.kubernetes.io/prefer-no-eviction (independently from its value) will be ignored by the descheduler.

KubeVirt is now able to dynamically propagate descheduler.alpha.kubernetes.io/prefer-no-eviction and descheduler.alpha.kubernetes.io/evict annotations to virt-launcher pods without the need to restart the VM.

The descheduler will check descheduler.alpha.kubernetes.io/evict and descheduler.alpha.kubernetes.io/prefer-no-eviction annotations: if both are present  descheduler.alpha.kubernetes.io/evict will win for backward compatibility reasons.
So when setting descheduler.alpha.kubernetes.io/prefer-no-eviction, the UI should also eventually remove descheduler.alpha.kubernetes.io/evict if present.

As a reference: https://github.com/kubevirt-ui/kubevirt-plugin/blob/main/src/views/catalog/wizard/tabs/scheduling/components/Descheduler.tsx#L32-L36

1. use the descheduler knob in the UI (VirtualMachine details / Configuration / Scheduling and resource requirements / Descheduler)
2.
3.

The UI is setting descheduler.alpha.kubernetes.io/evict to opt-in

The UI is setting descheduler.alpha.kubernetes.io/prefer-no-eviction to opt-out (eventually removing descheduler.alpha.kubernetes.io/evict if present).