From d0cd731b81a1e95edef869a9151176a1f173303f Mon Sep 17 00:00:00 2001
From: Jean-Marie Mineau <jean-marie.mineau@protonmail.com>
Date: Thu, 23 Sep 2021 17:57:01 +0200
Subject: [PATCH] use hostname for instance label instead of ip

---
 roles/prometheus-node-exporter/tasks/main.yml | 24 ++++++++++---------
 roles/prometheus/templates/prometheus.yml     |  5 +++-
 2 files changed, 17 insertions(+), 12 deletions(-)

diff --git a/roles/prometheus-node-exporter/tasks/main.yml b/roles/prometheus-node-exporter/tasks/main.yml
index 6dda7ad..e0490fa 100644
--- a/roles/prometheus-node-exporter/tasks/main.yml
+++ b/roles/prometheus-node-exporter/tasks/main.yml
@@ -96,14 +96,16 @@
   set_fact:
     server_target: "{{ server_target_file['content'] | b64decode | from_json }}"
 
-- 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
-
-- name: Put the new target list
-  copy:
-    content: "{{ server_target | to_nice_json }}"
-    dest: /etc/prometheus/node-targets.json
-  delegate_to: "{{ appointed_prometheus_server }}"
-
+- name: Register the node to the prometheus server
+  block:
+    - name: Add the node to the targets
+      set_fact:
+        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: "{{ 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
+    
diff --git a/roles/prometheus/templates/prometheus.yml b/roles/prometheus/templates/prometheus.yml
index 985620d..0d59dac 100644
--- a/roles/prometheus/templates/prometheus.yml
+++ b/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: