diff --git a/apps/emqx/test/emqx_common_test_helpers.erl b/apps/emqx/test/emqx_common_test_helpers.erl
index 8d2bd3ba3..3d770d8be 100644
--- a/apps/emqx/test/emqx_common_test_helpers.erl
+++ b/apps/emqx/test/emqx_common_test_helpers.erl
@@ -67,7 +67,8 @@
     emqx_cluster/2,
     start_epmd/0,
     start_slave/2,
-    stop_slave/1
+    stop_slave/1,
+    listener_port/2
 ]).
 
 -export([clear_screen/0]).
@@ -588,6 +589,12 @@ ensure_quic_listener(Name, UdpPort, ExtraSettings) ->
     %% Whether to execute `emqx_config:init_load(SchemaMod)`
     %% default: true
     load_schema => boolean(),
+    %% If we want to exercise the scenario where a node joins an
+    %% existing cluster where there has already been some
+    %% configuration changes (via cluster rpc), then we need to enable
+    %% autocluster so that the joining node will restart the
+    %% `emqx_conf' app and correctly catch up the config.
+    start_autocluster => boolean(),
     %% Eval by emqx_config:put/2
     conf => [{KeyPath :: list(), Val :: term()}],
     %% Fast option to config listener port
@@ -725,9 +732,24 @@ setup_node(Node, Opts) when is_map(Opts) ->
     %% we need a fresh data dir for each peer node to avoid unintended
     %% successes due to sharing of data in the cluster.
     PrivDataDir = maps:get(priv_data_dir, Opts, "/tmp"),
+    %% If we want to exercise the scenario where a node joins an
+    %% existing cluster where there has already been some
+    %% configuration changes (via cluster rpc), then we need to enable
+    %% autocluster so that the joining node will restart the
+    %% `emqx_conf' app and correctly catch up the config.
+    StartAutocluster = maps:get(start_autocluster, Opts, false),
 
     %% Load env before doing anything to avoid overriding
     lists:foreach(fun(App) -> rpc:call(Node, ?MODULE, load, [App]) end, LoadApps),
+    %% Ensure a clean mnesia directory for each run to avoid
+    %% inter-test flakiness.
+    MnesiaDataDir = filename:join([
+        PrivDataDir,
+        node(),
+        integer_to_list(erlang:unique_integer()),
+        "mnesia"
+    ]),
+    erpc:call(Node, application, set_env, [mnesia, dir, MnesiaDataDir]),
 
     %% Needs to be set explicitly because ekka:start() (which calls `gen`) is called without Handler
     %% in emqx_common_test_helpers:start_apps(...)
@@ -792,13 +814,10 @@ setup_node(Node, Opts) when is_map(Opts) ->
         undefined ->
             ok;
         _ ->
+            StartAutocluster andalso
+                (ok = rpc:call(Node, emqx_machine_boot, start_autocluster, [])),
             case rpc:call(Node, ekka, join, [JoinTo]) of
                 ok ->
-                    %% fix cluster rpc, as the conf app is not
-                    %% restarted with the current test procedure.
-                    StartApps andalso
-                        lists:member(emqx_conf, Apps) andalso
-                        (ok = erpc:call(Node, emqx_cluster_rpc, reset, [])),
                     ok;
                 ignore ->
                     ok;
@@ -872,6 +891,9 @@ base_port(Number) ->
 gen_rpc_port(BasePort) ->
     BasePort - 1.
 
+listener_port(Opts, Type) when is_map(Opts) ->
+    BasePort = maps:get(base_port, Opts),
+    listener_port(BasePort, Type);
 listener_port(BasePort, tcp) ->
     BasePort;
 listener_port(BasePort, ssl) ->
@@ -1057,7 +1079,7 @@ latency_up_proxy(off, Name, ProxyHost, ProxyPort) ->
 %% noise in the logs.
 call_janitor() ->
     Janitor = get_or_spawn_janitor(),
-    exit(Janitor, normal),
+    ok = emqx_test_janitor:stop(Janitor),
     ok.
 
 get_or_spawn_janitor() ->
diff --git a/apps/emqx/test/emqx_test_janitor.erl b/apps/emqx/test/emqx_test_janitor.erl
index 07d09aca1..703cba6da 100644
--- a/apps/emqx/test/emqx_test_janitor.erl
+++ b/apps/emqx/test/emqx_test_janitor.erl
@@ -30,6 +30,7 @@
 %% API
 -export([
     start_link/0,
+    stop/1,
     push_on_exit_callback/2
 ]).
 
@@ -40,6 +41,9 @@
 start_link() ->
     gen_server:start_link(?MODULE, self(), []).
 
+stop(Server) ->
+    gen_server:call(Server, terminate).
+
 push_on_exit_callback(Server, Callback) when is_function(Callback, 0) ->
     gen_server:call(Server, {push, Callback}).
 
@@ -56,6 +60,9 @@ terminate(_Reason, #{callbacks := Callbacks}) ->
 
 handle_call({push, Callback}, _From, State = #{callbacks := Callbacks}) ->
     {reply, ok, State#{callbacks := [Callback | Callbacks]}};
+handle_call(terminate, _From, State = #{callbacks := Callbacks}) ->
+    lists:foreach(fun(Fun) -> Fun() end, Callbacks),
+    {stop, normal, ok, State};
 handle_call(_Req, _From, State) ->
     {reply, error, State}.
 
diff --git a/apps/emqx_plugins/test/emqx_plugins_SUITE.erl b/apps/emqx_plugins/test/emqx_plugins_SUITE.erl
index f91233132..260ad1681 100644
--- a/apps/emqx_plugins/test/emqx_plugins_SUITE.erl
+++ b/apps/emqx_plugins/test/emqx_plugins_SUITE.erl
@@ -559,8 +559,8 @@ group_t_copy_plugin_to_a_new_node({'end', Config}) ->
     ok = rpc:call(CopyToNode, emqx_config, delete_override_conf_files, []),
     rpc:call(CopyToNode, ekka, leave, []),
     rpc:call(CopyFromNode, ekka, leave, []),
-    {ok, _} = emqx_common_test_helpers:stop_slave(CopyToNode),
-    {ok, _} = emqx_common_test_helpers:stop_slave(CopyFromNode),
+    ok = emqx_common_test_helpers:stop_slave(CopyToNode),
+    ok = emqx_common_test_helpers:stop_slave(CopyFromNode),
     ok = file:del_dir_r(proplists:get_value(to_install_dir, Config)),
     ok = file:del_dir_r(proplists:get_value(from_install_dir, Config));
 group_t_copy_plugin_to_a_new_node(Config) ->