Properly convert document as per bbe11b0f6a/docs/sources/set-up/migrate/from-promtail.md

nix-system-configs/modules/system/gramethus.nix

@@ -175,39 +175,34 @@ in {
       enable = true;
     };
 
+    # See: https://github.com/grafana/alloy/blob/bbe11b0f6a3bd3391108b2d27122c654c535dd8d/docs/sources/set-up/migrate/from-promtail.md
     environment.etc."alloy/config.alloy" = {
       text = ''
-        loki.relabel "journal" {
+        discovery.relabel "journal" {
+        	targets = []
+
         	rule {
         		source_labels = ["__journal__systemd_unit"]
         		target_label  = "unit"
         	}
         }
 
-        loki.write "local" {
+        loki.source.journal "journal" {
+        	max_age       = "12h0m0s"
+        	relabel_rules = discovery.relabel.journal.rules
+        	forward_to    = [loki.write.default.receiver]
+        	labels        = {
+        		host = "chrysalis",
+        		job  = "systemd-journal",
+        	}
+        }
+
+        loki.write "default" {
         	endpoint {
         		url = "http://127.0.0.1:3100/loki/api/v1/push"
         	}
         	external_labels = {}
         }
-
-        loki.source.journal "journal" {
-          max_age = "12h0m0s"
-
-          forward_to = [loki.write.local.receiver]
-
-          labels = {
-            job  = "systemd-journal"
-            host = "chrysalis"
-          }
-
-          relabel_rules = loki.relabel.journal.rules
-
-          legacy_position {
-            file = "/var/lib/grafana-agent/positions.yaml"
-            name = "journal"
-          }
-        }
       '';
       group = "root";
       mode = "0644";