use hostname for instance label instead of ip

roles/prometheus-node-exporter/tasks/main.yml

@@ -96,14 +96,16 @@
   set_fact:
     server_target: "{{ server_target_file['content'] | b64decode | from_json }}"
 
+- name: Register the node to the prometheus server
+  block:
     - name: Add the node to the targets
       set_fact:
-    server_target: "[{{ server_target[0] | combine({'targets': [lan_address]}, list_merge='append_rp') }}]"
-  when: lan_address not in server_target.0.targets
+        new_server_target: "[{{ server_target[0] | combine({'targets': [lan_address + '/' + ansible_facts['nodename']]}, list_merge='append_rp') }}]"
     
     - name: Put the new target list
       copy:
-    content: "{{ server_target | to_nice_json }}"
+        content: "{{ new_server_target | to_nice_json }}"
         dest: /etc/prometheus/node-targets.json
       delegate_to: "{{ appointed_prometheus_server }}"
+  when: (lan_address + '/' + ansible_facts['nodename']) not in server_target.0.targets
     

roles/prometheus/templates/prometheus.yml

@@ -37,13 +37,16 @@ scrape_configs:
       - files:
         - '/etc/prometheus/node-targets.json'
     relabel_configs:
-      # Do not put :9100 in instance name, rather here
+      # Use hostnames instead of ip for the instance label
       - source_labels: [__address__]
         target_label: __param_target
       - source_labels: [__param_target]
         target_label: instance
+        regex: '.*/(.*)'
+        replacement: '$1'
       - source_labels: [__param_target]
         target_label: __address__
+        regex: '(.*)/.*'
         replacement: '$1:9100'
     scheme: https
     tls_config: