Prometheus: Relabeling the node-exporter label

Added the reblabeling config lines to the kubernetes_sd_config key, to
replace the node_name with hostname for Node-exporter. This must now
display the hostname also as one of the labels of the Node-exporter
metrics.

Change-Id: Ic96a890552a1cd2f5e595c37330de048f31a0e75

prometheus/values.yaml

@@ -908,6 +908,19 @@ conf:
  - __meta_kubernetes_service_name
  target_label: job
  replacement: ${1}
+ - job_name: 'node-exporter'
+ kubernetes_sd_configs:
+ - role: endpoints
+ scrape_interval: 60s
+ relabel_configs:
+ - source_labels:
+ - __meta_kubernetes_service_name
+ action: keep
+ regex: 'node-exporter'
+ - source_labels:
+ - __meta_kubernetes_pod_node_name
+ action: replace
+ target_label: hostname
  - job_name: 'kubernetes-service-endpoints'
  kubernetes_sd_configs:
  - role: endpoints
@@ -916,7 +929,7 @@ conf:
  - source_labels:
  - __meta_kubernetes_service_name
  action: drop
- regex: '(openstack-metrics|prom-metrics|ceph-mgr)'
+ regex: '(openstack-metrics|prom-metrics|ceph-mgr|node-exporter)'
  - source_labels:
  - __meta_kubernetes_service_annotation_prometheus_io_scrape
  action: keep