fix: expose EPMD and Erlang RPC ports

Dockerfile

@@ -71,7 +71,8 @@ COPY --from=app-builder --chown=skate:skate /root/_build/prod/rel/skate .
 
 COPY --from=app-builder --chown=skate:skate /root/aws-cert-bundle.pem ./priv/aws-cert-bundle.pem
 
-EXPOSE 4000
+# Expose HTTP, EPMD, and Erlang RPC
+EXPOSE 4000 4369 57195
 
 ENTRYPOINT ["/usr/bin/dumb-init", "--"]
 

lib/notifications/notification_server.ex

@@ -8,6 +8,8 @@ defmodule Notifications.NotificationServer do
 
   use GenServer
 
+  require Logger
+
   alias Notifications.Bridge
   alias Notifications.Notification
   alias Notifications.NotificationReason
@@ -207,7 +209,13 @@ defmodule Notifications.NotificationServer do
 
     # Skate instances currently do not "specialize", and therefore we need to
     # send the notification to all instances
-    for node <- Node.list() do
+    nodes = Node.list()
+
+    Logger.info(
+      "notifying other instances of detour notification_id=#{notification_id} nodes=#{inspect(nodes)}"
+    )
+
+    for node <- nodes do
       GenServer.cast({server, node}, {:broadcast_new_detour_notification, notification_id})
     end
   end

rel/env.sh.eex

@@ -1,5 +1,11 @@
 #!/bin/sh
-INSTANCE_ID=$(curl --max-time 5 -s http://169.254.169.254/latest/meta-data/instance-id || true)
-if [ -n "${INSTANCE_ID}" ]; then
-    export RELEASE_NODE=skate-${INSTANCE_ID}
-fi
+ip_address=$(hostname -i)
+
+## Use "long names" for node names for Distributed Elixir
+## https://hexdocs.pm/elixir/main/config-and-releases.html#operating-system-environment-configuration
+export RELEASE_DISTRIBUTION=name
+## Set our node's "long name" so we can find each instance using DNSCluster
+export RELEASE_NODE="skate@$ip_address"
+
+echo "Release Distribution: $RELEASE_DISTRIBUTION"
+echo "Release Node: $RELEASE_NODE"

rel/vm.args.eex

@@ -3,3 +3,7 @@
 
 ## Give more memory to the literal allocator, used by :persistent_term
 +MIscs 2048
+
+## Set and restrict Erlang RPC port
+-kernel inet_dist_listen_min 57195
+-kernel inet_dist_listen_max 57195