Add a metrics package to add and expose metrics

* add a metrics package to handle metric registration and publishing
* add a metricsAddress field to the server struct
* make metrics a part of the server
* start a metrics endpoint as part of starting the controllers
* instrument backup_controller to report metrics
* update cli-reference docs
* update example deployments with prometheus annotations
* update 'pkg/install' tooling with prometheus annotations

Signed-off-by: Ashish Amarnath <ashish.amarnath@gmail.com>

examples/aws/10-deployment-kube2iam.yaml

@@ -26,6 +26,9 @@ spec:
         component: ark
       annotations:
         iam.amazonaws.com/role: arn:aws:iam::<AWS_ACCOUNT_ID>:role/<HEPTIO_ARK_ROLE_NAME>
+        prometheus.io/scrape: "true"
+        prometheus.io/port: "8085"
+        prometheus.io/path: "/metrics"
     spec:
       restartPolicy: Always
       serviceAccountName: ark

examples/aws/10-deployment.yaml

@@ -24,6 +24,10 @@ spec:
     metadata:
       labels:
         component: ark
+      annotations:
+        prometheus.io/scrape: "true"
+        prometheus.io/port: "8085"
+        prometheus.io/path: "/metrics"
     spec:
       restartPolicy: Always
       serviceAccountName: ark

examples/azure/00-ark-deployment.yaml

@@ -24,6 +24,10 @@ spec:
     metadata:
       labels:
         component: ark
+      annotations:
+        prometheus.io/scrape: "true"
+        prometheus.io/port: "8085"
+        prometheus.io/path: "/metrics"
     spec:
       restartPolicy: Always
       serviceAccountName: ark

examples/gcp/10-deployment.yaml

@@ -24,6 +24,10 @@ spec:
     metadata:
       labels:
         component: ark
+      annotations:
+        prometheus.io/scrape: "true"
+        prometheus.io/port: "8085"
+        prometheus.io/path: "/metrics"
     spec:
       restartPolicy: Always
       serviceAccountName: ark

examples/ibm/10-deployment.yaml

@@ -24,6 +24,10 @@ spec:
     metadata:
       labels:
         component: ark
+      annotations:
+        prometheus.io/scrape: "true"
+        prometheus.io/port: "8085"
+        prometheus.io/path: "/metrics"
     spec:
       restartPolicy: Always
       serviceAccountName: ark

examples/minio/20-ark-deployment.yaml

@@ -24,6 +24,10 @@ spec:
     metadata:
       labels:
         component: ark
+      annotations:
+        prometheus.io/scrape: "true"
+        prometheus.io/port: "8085"
+        prometheus.io/path: "/metrics"
     spec:
       restartPolicy: Always
       serviceAccountName: ark