New ejabberd command: migrate

Example usage:
$ ejabberdctl migrate 60

src/ejabberd_admin.erl

@@ -30,7 +30,7 @@
 -export([start/0, stop/0,
 	 %% Server
 	 status/0, reopen_log/0,
-         stop_migrate/1,
+         stop_migrate/1, migrate/1,
 	 stop_kindly/2, send_service_message_all_mucs/2,
 	 %% Erlang
 	 update_list/0, update/1,
@@ -91,6 +91,11 @@ commands() ->
 			module = ?MODULE, function = stop_kindly,
 			args = [{delay, integer}, {announcement, string}],
 			result = {res, rescode}},
+     #ejabberd_commands{name = migrate, tags = [server],
+                        desc = "Try to migrate C2S/BOSH/MUC sessions to other nodes",
+                        module = ?MODULE, function = migrate,
+			args = [{delay, integer}],
+			result = {res, rescode}},
      #ejabberd_commands{name = stop_migrate, tags = [server],
                         desc = "Try to migrate C2S/BOSH/MUC sessions to other"
                         "nodes and then stop",
@@ -329,6 +334,35 @@ send_service_message_all_mucs(Subject, AnnouncementText) ->
       end,
       ?MYHOSTS).
 
+%%%
+%%% Migrate w/o stopping
+%%%
+migrate(DelaySeconds) ->
+    WaitingDesc = io_lib:format("Starting migration, this will take ~p seconds",
+                                [DelaySeconds]),
+    Steps = [
+	     {"Stopping ejabberd port listeners",
+	      ejabberd_listener, stop_listeners, []},
+             {WaitingDesc, ejabberd_cluster, shutdown_migrate,
+              [DelaySeconds * 1000]}
+            ],
+    NumberLast = length(Steps),
+    TimestampStart = calendar:datetime_to_gregorian_seconds({date(), time()}),
+    lists:foldl(
+      fun({Desc, Mod, Func, Args}, NumberThis) ->
+	      SecondsDiff =
+		  calendar:datetime_to_gregorian_seconds({date(), time()})
+		  - TimestampStart,
+	      io:format("[~p/~p ~ps] ~s... ",
+			[NumberThis, NumberLast, SecondsDiff, Desc]),
+	      Result = apply(Mod, Func, Args),
+	      io:format("~p~n", [Result]),
+	      NumberThis+1
+      end,
+      1,
+      Steps),
+    ok.
+
 %%%
 %%% Migrate and stop
 %%%