[Prometheus] Updated cAdvisor endpoint (#3684)

* Updated values.yaml cadvisor endpoint

Updated cadvisor scape endpoint so that it is compatible with Kubernetes 1.7.3+
See more here https://github.com/prometheus/prometheus/issues/3181#issuecomment-329927699

* Added extensive description about the problem with cadvisor

* Bumped chart version

* Removed trailing spaces

* Update Chart.yaml

stable/prometheus/Chart.yaml

@@ -1,5 +1,5 @@
 name: prometheus
-version: 5.1.7
+version: 5.2.1
 description: Prometheus is a monitoring system and time series database.
 home: https://prometheus.io/
 icon: https://raw.githubusercontent.com/prometheus/prometheus.github.io/master/assets/prometheus_logo-cb55bb5c346.png

stable/prometheus/values.yaml

@@ -780,6 +780,11 @@ serverFiles:
         kubernetes_sd_configs:
           - role: node
 
+        # This configuration will work only on kubelet 1.7.3+
+        # As the scrape endpoints for cAdvisor have changed
+        # if you are using older version you need to change the replacement to
+        # replacement: /api/v1/nodes/${1}:4194/proxy/metrics
+        # more info here https://github.com/coreos/prometheus-operator/issues/633
         relabel_configs:
           - action: labelmap
             regex: __meta_kubernetes_node_label_(.+)
@@ -788,7 +793,7 @@ serverFiles:
           - source_labels: [__meta_kubernetes_node_name]
             regex: (.+)
             target_label: __metrics_path__
-            replacement: /api/v1/nodes/${1}:4194/proxy/metrics
+            replacement: /api/v1/nodes/${1}/proxy/metrics/cadvisor
 
       # Scrape config for service endpoints.
       #