Monitor cluster partition event (#2814)

rebar.config

@@ -3,7 +3,7 @@
      {cowboy, "2.6.1"}, % hex
      {gproc, "0.8.0"}, % hex
      {esockd, "5.5.0"}, %hex
-     {ekka, "0.6.0"}, %hex
+     {ekka, "0.6.1"}, %hex
      {gen_rpc, {git, "https://github.com/emqx/gen_rpc", {tag, "2.4.1"}}},
      {cuttlefish, {git, "https://github.com/emqx/cuttlefish", {tag, "v3.0.0"}}}
     ]}.

src/emqx_sys_mon.erl

@@ -57,6 +57,10 @@ start_link(Opts) ->
 init([Opts]) ->
     erlang:system_monitor(self(), parse_opt(Opts)),
     emqx_logger:set_proc_metadata(#{sysmon => true}),
+
+    %% Monitor cluster partition event
+    ekka:monitor(partition, fun handle_partition_event/1),
+
     {ok, start_timer(#{timer => undefined, events => []})}.
 
 start_timer(State) ->
@@ -156,6 +160,15 @@ terminate(_Reason, #{timer := TRef}) ->
 code_change(_OldVsn, State, _Extra) ->
     {ok, State}.
 
+%%--------------------------------------------------------------------
+%% Internal Functions
+%%--------------------------------------------------------------------
+
+handle_partition_event({partition, {occurred, Node}}) ->
+    alarm_handler:set_alarm({partitioned, Node});
+handle_partition_event({partition, {healed, Node}}) ->
+    alarm_handler:clear_alarm(partitioned).
+
 suppress(Key, SuccFun, State = #{events := Events}) ->
     case lists:member(Key, Events) of
         true  -> {noreply, State};