use file for node-targets

roles/prometheus/tasks/main.yml

@@ -29,7 +29,18 @@
   notify: Restart prometheus
   no_log: true
 
-- name: Setup the arguments for node-exporter
+- name: Add node targets file
+  template:
+    src: node-targets.json
+    dest: /etc/prometheus/node-targets.json
+    owner: prometheus
+    group: prometheus
+    mode: '0640'
+    force: no
+  notify: Restart prometheus
+  no_log: true
+
+- name: Setup the arguments for prometheus
   template:
     src: prometheus
     dest: /etc/default/prometheus

roles/prometheus/templates/node-targets.json

@@ -0,0 +1,6 @@
+[
+    {
+        "targets": [
+        ]
+    }
+]

roles/prometheus/templates/prometheus.yml

@@ -33,7 +33,15 @@ scrape_configs:
       - targets: ['{{ lan_address }}:9090']
 
   - job_name: node
-    # If prometheus-node-exporter is installed, grab stats about the local
-    # machine by default.
-    static_configs:
-      - targets: ['{{ lan_address }}:9100']
+    file_sd_configs:
+      - files:
+        - '/etc/prometheus/node-targets.json'
+    relabel_configs:
+      # Do not put :9100 in instance name, rather here
+      - source_labels: [__address__]
+        target_label: __param_target
+      - source_labels: [__param_target]
+        target_label: instance
+      - source_labels: [__param_target]
+        target_label: __address__
+        replacement: '$1:9100'