diff --git a/apps/emqx_bridge_rabbitmq/src/emqx_bridge_rabbitmq_connector.erl b/apps/emqx_bridge_rabbitmq/src/emqx_bridge_rabbitmq_connector.erl
index ff439b676..2af1c16c8 100644
--- a/apps/emqx_bridge_rabbitmq/src/emqx_bridge_rabbitmq_connector.erl
+++ b/apps/emqx_bridge_rabbitmq/src/emqx_bridge_rabbitmq_connector.erl
@@ -20,7 +20,7 @@
 -behaviour(ecpool_worker).
 
 %% hocon_schema callbacks
--export([roots/0, fields/1]).
+-export([namespace/0, roots/0, fields/1]).
 
 %% HTTP API callbacks
 -export([values/1]).
@@ -43,6 +43,8 @@
 %% Internal callbacks
 -export([publish_messages/3]).
 
+namespace() -> "rabbitmq".
+
 roots() ->
     [{config, #{type => hoconsc:ref(?MODULE, config)}}].
 
diff --git a/apps/emqx_ldap/src/emqx_ldap.erl b/apps/emqx_ldap/src/emqx_ldap.erl
index bb16efbda..1c0c7124f 100644
--- a/apps/emqx_ldap/src/emqx_ldap.erl
+++ b/apps/emqx_ldap/src/emqx_ldap.erl
@@ -59,7 +59,7 @@
 %% Hocon schema
 
 namespace() -> "ldap".
- 
+
 roots() ->
     [{config, #{type => hoconsc:ref(?MODULE, config)}}].
 
diff --git a/apps/emqx_license/src/emqx_license_schema.erl b/apps/emqx_license/src/emqx_license_schema.erl
index 8f2d7f20d..f2b91811e 100644
--- a/apps/emqx_license/src/emqx_license_schema.erl
+++ b/apps/emqx_license/src/emqx_license_schema.erl
@@ -13,12 +13,14 @@
 
 -behaviour(hocon_schema).
 
--export([roots/0, fields/1, validations/0, desc/1, tags/0]).
+-export([namespace/0, roots/0, fields/1, validations/0, desc/1, tags/0]).
 
 -export([
     default_license/0
 ]).
 
+namespace() -> "license".
+
 roots() ->
     [
         {license,
diff --git a/apps/emqx_rule_engine/src/emqx_rule_api_schema.erl b/apps/emqx_rule_engine/src/emqx_rule_api_schema.erl
index 0424bfb60..e9adbbdf6 100644
--- a/apps/emqx_rule_engine/src/emqx_rule_api_schema.erl
+++ b/apps/emqx_rule_engine/src/emqx_rule_api_schema.erl
@@ -24,7 +24,7 @@
 
 -export([check_params/2]).
 
--export([roots/0, fields/1]).
+-export([namespace/0, roots/0, fields/1]).
 
 -type tag() :: rule_creation | rule_test | rule_engine.
 
@@ -46,6 +46,8 @@ check_params(Params, Tag) ->
 %%======================================================================================
 %% Hocon Schema Definitions
 
+namespace() -> "rule_engine".
+
 roots() ->
     [
         {"rule_engine", sc(ref("rule_engine"), #{desc => ?DESC("root_rule_engine")})},
diff --git a/apps/emqx_telemetry/src/emqx_telemetry_schema.erl b/apps/emqx_telemetry/src/emqx_telemetry_schema.erl
index 1e1f547c5..586b70f72 100644
--- a/apps/emqx_telemetry/src/emqx_telemetry_schema.erl
+++ b/apps/emqx_telemetry/src/emqx_telemetry_schema.erl
@@ -22,11 +22,15 @@
 -behaviour(hocon_schema).
 
 -export([
+    namespace/0,
     roots/0,
     fields/1,
     desc/1
 ]).
 
+%% 'emqxtel' to distinguish open-telemetry
+namespace() -> "emqxtel".
+
 roots() -> ["telemetry"].
 
 fields("telemetry") ->