v-m: Scrape Promtail

The *promtail* job scrapes metrics from all the hosts running Promtail.
The static targets are Fedora CoreOS nodes that are not part of the
Kubernetes cluster.

The relabeling rules ensure that both the static targets and the
targets discovered via the Kubernetes Node API use the FQDN of the host
as the value of the *instance* label.

victoria-metrics/scrape.yml

@@ -307,3 +307,29 @@ scrape_configs:
   static_configs:
   - targets:
     - loki.pyrocufflink.blue
+
+- job_name: promtail
+  static_configs:
+  - targets:
+    - loki0.pyrocufflink.blue
+    - nut0.pyrocufflink.blue
+    - nvr1.pyrocufflink.blue
+    - serial1.pyrocufflink.blue
+  kubernetes_sd_configs:
+  - role: pod
+    namespaces:
+      names:
+      - promtail
+    selectors:
+    - role: pod
+      label: app.kubernetes.io/name=promtail
+  relabel_configs:
+  - source_labels: [__address__]
+    target_label: instance
+  - source_labels: [__meta_kubernetes_pod_node_name]
+    regex: '(.+)'
+    target_label: instance
+  - source_labels: [__address__]
+    target_label: __address__
+    regex: '([^:]+)'
+    replacement: '$1:9080'