[feature] Add support for virtual kubelet/kip for bursting to public clouds

[David Coronel]

This is a feature request to add a Virtual Kubelet[1] provider like Kip[2] to Charmed Kubernetes.

Virtual Kubelet is an open source Kubernetes kubelet implementation that masquerades as a kubelet for the purposes of connecting Kubernetes to other APIs.

Kip is a Virtual Kubelet provider that allows a Kubernetes cluster to transparently launch pods onto their own cloud instances. The kip pod is run on a cluster and will create a virtual Kubernetes node in the cluster. When a pod is scheduled onto the Virtual Kubelet, Kip starts a right-sized cloud instance for the pod’s workload and dispatches the pod onto the instance. When the pod is finished running, the cloud instance is terminated.

Adding for support for a Virtual Kubelet provider like Kip would allow Charmed Kubernetes to burst to the public cloud easily when the load on the cluster exceeds the local resources.

[1] https://github.com/virtual-kubelet/virtual-kubelet
[2] https://github.com/elotl/kip/blob/master/README.md