hosts/monitoring-3: use primary fqdn for instance label in prometheus

hosts/monitoring-3/configuration.nix

@@ -131,7 +131,14 @@ in {
   services.prometheus = {
     enable = true;
     listenAddress = "[::1]";
-    scrapeConfigs = [
+    scrapeConfigs = let
+      relabelAddressToInstance = {
+        source_labels = [ "__address__" ];
+        target_label = "instance";
+        regex = ''([\w-]+)\.mon\.clerie\.de\:\d+'';
+        replacement = "\${1}.net.clerie.de";
+      };
+    in [
       {
         job_name = "prometheus";
         scrape_interval = "20s";
@@ -143,6 +150,9 @@ in {
             ];
           }
         ];
+        relabel_configs = [
+          relabelAddressToInstance
+        ];
       }
       {
         job_name = "node-exporter";
@@ -155,6 +165,9 @@ in {
             ++ monitoringTargets;
           }
         ];
+        relabel_configs = [
+          relabelAddressToInstance
+        ];
       }
       {
         job_name = "nixos-exporter";
@@ -164,6 +177,9 @@ in {
             targets = nixosMonitoringTargets;
           }
         ];
+        relabel_configs = [
+          relabelAddressToInstance
+        ];
       }
       {
         job_name = "bird-exporter";
@@ -173,6 +189,9 @@ in {
             targets = birdMonitoringTargets;
           }
         ];
+        relabel_configs = [
+          relabelAddressToInstance
+        ];
       }
       {
         job_name = "blackbox_icmp6";
@@ -211,10 +230,7 @@ in {
             target_label = "__address__";
             replacement = "\${1}";
           }
-          {
+          relabelAddressToInstance
-            source_labels = [ "__address__" ];
-            target_label = "instance";
-          }
         ];
       }
       {
@@ -255,10 +271,7 @@ in {
             target_label = "__address__";
             replacement = "\${1}";
           }
-          {
+          relabelAddressToInstance
-            source_labels = [ "__address__" ];
-            target_label = "instance";
-          }
         ];
       }
       {
@@ -297,6 +310,9 @@ in {
             ];
           }
         ];
+        relabel_configs = [
+          relabelAddressToInstance
+        ];
       }
     ];
     alertmanagers = [