modificato conf alloy e compose x hostname in grafana

vm1/alloy-config.alloy

@@ -63,10 +63,26 @@ prometheus.exporter.unix "host" {
   rootfs_path = "/host/root"
 }
 
+// Relabel configuration for Prometheus metrics
+prometheus.relabel "host_metrics" {
+  forward_to = [prometheus.remote_write.mimir.receiver]
+
+  rule {
+    source_labels = ["__address__"]
+    target_label  = "instance"
+    replacement   = "vm1"
+  }
+
+  rule {
+    target_label  = "hostname"
+    replacement   = "vm1"
+  }
+}
+
 // Scrape metrics from the unix exporter
 prometheus.scrape "host" {
   targets    = prometheus.exporter.unix.host.targets
-  forward_to = [prometheus.remote_write.mimir.receiver]
+  forward_to = [prometheus.relabel.host_metrics.receiver]
 }
 
 // Write metrics to Mimir/Prometheus