Update prometheus service discovery for openstack-exporter

This updates the prometheus service discovery configuration
to define the openstack-exporter service discovery separate from
the other services. This allows for relabeling the instance label
for the openstack-exporter service, removing the potential for
multiple data series being returned by the single stat panels in
the Grafana dashboards for the openstack services. As the other
services perform as expected when exporter pods restart, they
remain configured the same as before.

Change-Id: Iad4c56d31fb553a9629f5a6fd1eac5464207add4
Signed-off-by: Steve Wilkerson <wilkers.steve@gmail.com>

prometheus/values.yaml

@@ -345,11 +345,63 @@ conf:
         # * `prometheus.io/path`: If the metrics path is not `/metrics` override this.
         # * `prometheus.io/port`: If the metrics are exposed on a different port to the
         # service then set this appropriately.
+        - job_name: 'openstack-exporter'
+          kubernetes_sd_configs:
+          - role: endpoints
+          scrape_interval: 60s
+          relabel_configs:
+          - source_labels:
+              - __meta_kubernetes_service_name
+            action: keep
+            regex: "openstack-metrics"
+          - source_labels:
+              - __meta_kubernetes_service_annotation_prometheus_io_scrape
+            action: keep
+            regex: true
+          - source_labels:
+              - __meta_kubernetes_service_annotation_prometheus_io_scheme
+            action: replace
+            target_label: __scheme__
+            regex: (https?)
+          - source_labels:
+              - __meta_kubernetes_service_annotation_prometheus_io_path
+            action: replace
+            target_label: __metrics_path__
+            regex: (.+)
+          - source_labels:
+              - __address__
+              - __meta_kubernetes_service_annotation_prometheus_io_port
+            action: replace
+            target_label: __address__
+            regex: ([^:]+)(?::\d+)?;(\d+)
+            replacement: $1:$2
+          - action: labelmap
+            regex: __meta_kubernetes_service_label_(.+)
+          - source_labels:
+              - __meta_kubernetes_namespace
+            action: replace
+            target_label: kubernetes_namespace
+          - source_labels:
+              - __meta_kubernetes_service_name
+            action: replace
+            target_label: instance
+          - source_labels:
+              - __meta_kubernetes_service_name
+            action: replace
+            target_label: kubernetes_name
+          - source_labels:
+              - __meta_kubernetes_service_name
+            target_label: job
+            replacement: ${1}
         - job_name: 'kubernetes-service-endpoints'
           kubernetes_sd_configs:
           - role: endpoints
           scrape_interval: 60s
           relabel_configs:
+          - source_labels:
+              - __meta_kubernetes_service_name
+            action: drop
+            regex: "openstack-metrics"
           - source_labels:
               - __meta_kubernetes_service_annotation_prometheus_io_scrape
             action: keep