diff --git a/apps/emqx/src/emqx_metrics.erl b/apps/emqx/src/emqx_metrics.erl
index 529b1b431..8aabd7ac8 100644
--- a/apps/emqx/src/emqx_metrics.erl
+++ b/apps/emqx/src/emqx_metrics.erl
@@ -337,11 +337,17 @@ all() ->
 %% @doc Get metric value
 -spec val(metric_name()) -> non_neg_integer().
 val(Name) ->
-    case ets:lookup(?TAB, Name) of
-        [#metric{idx = Idx}] ->
-            CRef = persistent_term:get(?MODULE),
-            counters:get(CRef, Idx);
-        [] ->
+    try
+        case ets:lookup(?TAB, Name) of
+            [#metric{idx = Idx}] ->
+                CRef = persistent_term:get(?MODULE),
+                counters:get(CRef, Idx);
+            [] ->
+                0
+        end
+        %% application will restart when join cluster, then ets not exist.
+    catch
+        error:badarg ->
             0
     end.
 
diff --git a/apps/emqx_conf/etc/emqx_conf.conf b/apps/emqx_conf/etc/emqx_conf.conf
index 7d608031d..6f5478c52 100644
--- a/apps/emqx_conf/etc/emqx_conf.conf
+++ b/apps/emqx_conf/etc/emqx_conf.conf
@@ -13,6 +13,7 @@ node {
   cookie: emqxsecretcookie
   data_dir: "{{ platform_data_dir }}"
   etc_dir: "{{ platform_etc_dir }}"
+  applications: "{{ emqx_machine_boot_apps }}"
 }
 
 log {