Explore kubevirt live migration capabilities

[wozniakjan]

Upstream KubeVirt has some support for live migration already implemented
https://kubevirt.io/user-guide/operations/live_migration/

For KKP, we should explore the possibility of leveraging this live migration to improve the maintenance tasks experience for administrators.

[wozniakjan]

so far I made two changes to machine-controller

• allow hardcoded volume type to change between RWO and RWX
• allow network interface change from bridge to masquerade (no other type supports live migration yet)

I am battling with the node address diff between virt-launcher pod and VM node

logs:
E1129 13:43:01.201737       1 node_controller.go:236] error syncing 'migratable-54bd4d84c5-82g89': failed to get node modifiers from cloud provider: provided node ip for node "migratable-54bd4d84c5-82g89" is not valid: failed to get node address from cloud provider that matches ip: 10.0.2.2, requeuing

$ k get node -o wide
NAME                                        STATUS   ROLES    AGE   VERSION   INTERNAL-IP    EXTERNAL-IP   OS-IMAGE             KERNEL-VERSION      CONTAINER-RUNTIME
migratable-54bd4d84c5-82g89                 Ready    <none>   19m   v1.27.6   10.0.2.2       <none>        Ubuntu 22.04.1 LTS   5.15.0-57-generic   containerd://1.6.25

$ k get po -o wide
NAME                                                            READY   STATUS    RESTARTS   AGE     IP             NODE         NOMINATED NODE   READINESS GATES
virt-launcher-migratable-54bd4d84c5-82g89-v86cv                 1/1     Running   0          4h1m    10.244.0.240   kubevirt-1   <none>           1/1

I'm checking if it's possible to assign the node IP or apply some modifier on cloud-provider level

[wozniakjan]

reference for upstream PR supporting live migration for bridge network kubevirt/community#182

[wozniakjan]

kubevirt/kubevirt#9193 supports annotation override to override experimental live-migration for bridge with CNIs that allow IP address carry over for pods.