add clustering

config/runtime.exs

@@ -71,6 +71,23 @@ if config_env() == :prod do
     aprs_is_login_id: System.get_env("APRS_CALLSIGN"),
     aprs_is_password: System.get_env("APRS_PASSCODE")
 
+  app_name =
+    System.get_env("FLY_APP_NAME") ||
+      raise "FLY_APP_NAME not available"
+
+  config :libcluster,
+    debug: true,
+    topologies: [
+      fly6pn: [
+        strategy: Cluster.Strategy.DNSPoll,
+        config: [
+          polling_interval: 5_000,
+          query: "#{app_name}.internal",
+          node_basename: app_name
+        ]
+      ]
+    ]
+
   # ## SSL Support
   #
   # To get SSL working, you will need to add the `https` key