poc for node-fence

[bronhaim]

• simple controller (doesn't work yet with workqueue)
• initialize new crd for fence objects with status field
• polling nodefence object and start "executions"
• execution parse the configuration for node, and start running "isolation" phase methods

under demo directory we have:

• templates-fenceconfigs.yaml which includes configmaps for all fence method templates in cluster.
• demo-host0-fenceconfigs which includes fence configuration for node name lago-kube-host0

running that and killing kubelet service in node lago-kube-host0 will trigger the controller to create nodefence object in the format

apiVersion: ha.k8s.io/v1
clean_resources: true
hostname: localhost   <-- here we update where execution ran (should modified to node name)
kind: NodeFence
node: lago-kube-host0
status: New   <-- this is updated by controller after getting execution output
step: Power-Management

deployment:

• make container - produce an image that can be used by standalone-controller/deployment.yaml - this is pod definition to run the controller (open issue: use https://github.com/kubernetes/client-go/tree/master/examples/in-cluster-client-configuration instead of passing the config while creating the container)