Add metric collection to charms for autoscalling

cluster/juju/.gitignore

+builds
+deps

cluster/juju/layers/kubeapi-load-balancer/layer.yaml

 repo: https://github.com/kubernetes/kubernetes.git
 includes:
+  - 'layer:metrics'
   - 'layer:nagios'
   - 'layer:nginx'
   - 'layer:tls-client'

cluster/juju/layers/kubeapi-load-balancer/metrics.yaml

+metrics:
+  juju-units: {}

cluster/juju/layers/kubernetes-master/layer.yaml

 repo: https://github.com/kubernetes/kubernetes.git
 includes:
   - 'layer:basic'
-  - 'layer:tls-client'
-  - 'layer:leadership'
   - 'layer:debug'
+  - 'layer:leadership'
+  - 'layer:metrics'
   - 'layer:nagios'
+  - 'layer:tls-client'
   - 'interface:ceph-admin'
   - 'interface:etcd'
   - 'interface:http'

cluster/juju/layers/kubernetes-master/metrics.yaml

+metrics:
+  juju-units: {}
+  pods:
+    type: gauge
+    description: number of pods
+    command: kubectl get po --all-namespaces | tail -n+2 | wc -l
+  services:
+    type: gauge
+    description: number of services
+    command: kubectl get svc --all-namespaces | tail -n+2 | wc -l
+  replicasets:
+    type: gauge
+    description: number of replicasets
+    command: kubectl get rs --all-namespaces | tail -n+2 | wc -l
+  replicationcontrollers:
+    type: gauge
+    description: number of replicationcontrollers
+    command: kubectl get rc --all-namespaces | tail -n+2 | wc -l
+  nodes:
+    type: gauge
+    description: number of kubernetes nodes
+    command: kubectl get nodes | tail -n+2 | wc -l
+  persistentvolume:
+    type: gauge
+    description: number of pv
+    command: kubectl get pv --all-namespaces | tail -n+2 | wc -l
+  persistentvolumeclaims:
+    type: gauge
+    description: number of claims
+    command: kubectl get pvc --all-namespaces | tail -n+2 | wc -l
+  serviceaccounts:
+    type: gauge
+    description: number of sa
+    command: kubectl get sa --all-namespaces | tail -n+2 | wc -l

cluster/juju/layers/kubernetes-worker/layer.yaml

@@ -3,6 +3,7 @@ includes:
   - 'layer:basic'
   - 'layer:debug'
   - 'layer:docker'
+  - 'layer:metrics'
   - 'layer:nagios'
   - 'layer:tls-client'
   - 'layer:nvidia-cuda'

cluster/juju/layers/kubernetes-worker/metrics.yaml

+metrics:
+  juju-units: {}