feat(controller): add virtink infrastructure provider

[jseguillon]

virtink is a solution to deploy micro-vms in Kubernetes. It supports ClusterAPI.

It's a small project but it works very well and coupling it with Kamaji gives great results.

I propose to include it in Kamaji with this PR.

[prometherion]

We're happy when Kamaji can easily integrate with other community projects, and we're definitely open to this.

However, I'm not sure the integration with virtink CAPI works without any issue, mostly due to this:
https://github.com/smartxworks/cluster-api-provider-virtink/blob/cf3d5668db51a8ff1674c53a4e1df715631d7ce4/controllers/virtinkcluster_controller.go#L150

Essentially, the provider takes for granted it has to create a Service for the Control Planes, however this is already managed by Kamaji.

We have 2 options here:

1. Interact with the Virtink community, explain the use case, and add a flag, or an annotation, to wait the assignment of a control plane address by external Control Plane providers
2. as we're doing with Kubevirt, let ignore the Cluster handler using the CAPI annotation (managed-by) in order to let Kamaji creates the Service and patch the Control Planes Endpoint field.

[jseguillon]

Hi,
FYI here is the cluster yaml source if you want to reproduce and test a kamaji + virtink cluster : https://gist.github.com/jseguillon/1e588d3cea095ce67ecce205f29fd89f

Indeed I got into trouble with services and had to patch a little in order to make this cluster work. Reason is default control plane service does not have any endpoint:

NAME                        ENDPOINTS                                                        AGE
capi-kamaji-virtink00       <none>                                                           3m24s
capi-kamaji-virtink00-kcp   10.42.0.162:6443,10.42.0.163:6443,10.42.0.164:6443 + 3 more...   11d
kubernetes                  172.19.34.189:6443                                               6d6h

In the example gist you may notice I superset the controlplane endpoint in order to get a working cluster:

apiVersion: cluster.x-k8s.io/v1beta2
kind: Cluster
...
  controlPlaneEndpoint:                        
    host: capi-kamaji-virtink00-kcp.default.svc
    port: 6443

I did try to tweak annotations with:

apiVersion: infrastructure.cluster.x-k8s.io/v1beta1
kind: VirtinkCluster
...
spec:
  controlPlaneServiceTemplate:
    metadata:
      annotations:
        cluster.x-k8s.io/managed-by: kamaji
      namespace: default

but it did not help.

Maybe there are some things I still dont' understand ? I'm new user of both Kamaji and virtink :)

Please let me know if I can give more information to help you add virtink in Kamaji.

PS: I also pushed up to date container images. Those are still work in progress and probably os container is sub-optimal in term of layers size but it should be good enough to help you test the gist I gave you.

[prometherion]

@jseguillon you have to disable using the annotation cluster.x-k8s.io/managed-by on the Infrastructure Cluster: https://github.com/clastix/cluster-api-control-plane-provider-kamaji/blame/955882eed5a67e3cb45b9a3d87f7bbe793793433/docs/providers-kubevirt.md#L44-L50