add option allow_experimental_cluster_discovery

src/Core/Settings.h

@@ -549,6 +549,8 @@ class IColumn;
     /** Experimental functions */ \
     M(Bool, allow_experimental_funnel_functions, false, "Enable experimental functions for funnel analysis.", 0) \
     M(Bool, allow_experimental_nlp_functions, false, "Enable experimental functions for natural language processing.", 0) \
+    \
+    M(Bool, allow_experimental_cluster_discovery, false, "Enable automatic cluster discovery via ZooKeeper", 0) \
 
 // End of COMMON_SETTINGS
 // Please add settings related to formats into the FORMAT_FACTORY_SETTINGS and move obsolete settings to OBSOLETE_SETTINGS.

src/Interpreters/Context.cpp

@@ -2210,7 +2210,7 @@ void Context::setClustersConfig(const ConfigurationPtr & config, bool enable_dis
 {
     std::lock_guard lock(shared->clusters_mutex);
 
-    if (enable_discovery && !shared->cluster_discovery)
+    if (/* getSettingsRef().allow_experimental_cluster_discovery && */ enable_discovery && !shared->cluster_discovery)
     {
         shared->cluster_discovery = std::make_unique<ClusterDiscovery>(*config, getGlobalContext());
     }

tests/integration/test_cluster_discovery/config/settings.xml

@@ -0,0 +1,12 @@
+<clickhouse>
+    <profiles>
+        <default>
+            <allow_experimental_cluster_discovery>1</allow_experimental_cluster_discovery>
+        </default>
+    </profiles>
+    <users>
+        <default>
+            <profile>default</profile>
+        </default>
+    </users>
+</clickhouse>

tests/integration/test_cluster_discovery/test.py

@@ -9,6 +9,7 @@ nodes = [
     cluster.add_instance(
         f'node{i}',
         main_configs=['config/config.xml'],
+        user_configs=['config/settings.xml'],
         stay_alive=True,
         with_zookeeper=True
     ) for i in range(5)