Release series support: announce in more places

* Log file on boot
 * Startup banner
 * HTTP API response @ GET /api/overview

deps/rabbit/src/rabbit.erl

@@ -691,10 +691,7 @@ status() ->
         [Tuple] when is_tuple(Tuple) -> Tuple;
         Tuple   when is_tuple(Tuple) -> Tuple
     end,
-    SeriesSupportStatus = case rabbit_release_series:is_currently_supported() of
-        false -> <<"out of support">>;
-        _     -> <<"supported">>
-    end,
+    SeriesSupportStatus = rabbit_release_series:readable_support_status(),
     S1 = [{pid,                  list_to_integer(os:getpid())},
           %% The timeout value used is twice that of gen_server:call/2.
           {running_applications, rabbit_misc:which_applications()},
@@ -865,6 +862,7 @@ start(normal, []) ->
                     ?COPYRIGHT_MESSAGE, ?INFORMATION_MESSAGE],
                    #{domain => ?RMQLOG_DOMAIN_PRELAUNCH})
         end,
+        maybe_warn_about_release_series_eol(),
         log_motd(),
         {ok, SupPid} = rabbit_sup:start_link(),
 
@@ -1188,6 +1186,7 @@ print_banner() ->
     %% padded list lines
     {LogFmt, LogLocations} = LineListFormatter("~n        ~ts", log_locations()),
     {CfgFmt, CfgLocations} = LineListFormatter("~n                  ~ts", config_locations()),
+    SeriesSupportStatus    = rabbit_release_series:readable_support_status(),
     {MOTDFormat, MOTDArgs} = case motd() of
                                  undefined ->
                                      {"", []};
@@ -1205,6 +1204,7 @@ print_banner() ->
               MOTDFormat ++
               "~n  Erlang:      ~ts [~ts]"
               "~n  TLS Library: ~ts"
+              "~n  Release series support status: ~ts"
               "~n"
               "~n  Doc guides:  https://rabbitmq.com/documentation.html"
               "~n  Support:     https://rabbitmq.com/contact.html"
@@ -1215,11 +1215,22 @@ print_banner() ->
               "~n  Config file(s): ~ts" ++ CfgFmt ++ "~n"
               "~n  Starting broker...",
               [Product, Version, ?COPYRIGHT_MESSAGE, ?INFORMATION_MESSAGE] ++
-              [rabbit_misc:otp_release(), emu_flavor(), crypto_version()] ++
+              [rabbit_misc:otp_release(), emu_flavor(), crypto_version(),
+               SeriesSupportStatus] ++
               MOTDArgs ++
               LogLocations ++
               CfgLocations).
 
+maybe_warn_about_release_series_eol() ->
+    case rabbit_release_series:is_currently_supported() of
+        false ->
+            ?LOG_WARNING("This release series has reached end of life "
+                         "and is no longer supported. "
+                         "Please visit https://rabbitmq.com/versions.html "
+                         "to learn more and upgrade");
+        _ -> ok
+    end.
+
 emu_flavor() ->
     %% emu_flavor was introduced in Erlang 24 so we need to catch the error on Erlang 23
     case catch(erlang:system_info(emu_flavor)) of

deps/rabbit/src/rabbit_release_series.erl

@@ -11,7 +11,8 @@
 
 -export([
   eol_date/0,
-  is_currently_supported/0
+  is_currently_supported/0,
+  readable_support_status/0
 ]).
 
 -spec eol_date() -> rabbit_types:maybe(calendar:date()).
@@ -29,3 +30,10 @@ is_currently_supported() ->
     none -> true;
     Date -> not rabbit_date_time:is_in_the_past(Date)
   end.
+
+-spec readable_support_status() -> binary().
+readable_support_status() ->
+    case is_currently_supported() of
+      false -> <<"out of support">>;
+      _     -> <<"supported">>
+  end.

deps/rabbitmq_management/src/rabbit_mgmt_wm_overview.erl

@@ -49,8 +49,9 @@ to_json(ReqData, Context = #context{user = User = #user{tags = Tags}}) ->
                  {cluster_name,              rabbit_nodes:cluster_name()},
                  {erlang_version,            erlang_version()},
                  {erlang_full_version,       erlang_full_version()},
-                 {disable_stats,             rabbit_mgmt_util:disable_stats(ReqData)},
-                 {enable_queue_totals,       rabbit_mgmt_util:enable_queue_totals(ReqData)}],
+                 {release_series_support_status, rabbit_release_series:readable_support_status()},
+                 {disable_stats,                 rabbit_mgmt_util:disable_stats(ReqData)},
+                 {enable_queue_totals,           rabbit_mgmt_util:enable_queue_totals(ReqData)}],
     try
         case rabbit_mgmt_util:disable_stats(ReqData) of
             false ->