diff --git a/citus-tools b/citus-tools
new file mode 160000
index 000000000..3376bd684
--- /dev/null
+++ b/citus-tools
@@ -0,0 +1 @@
+Subproject commit 3376bd6845f0614908ed304f5033bd644c82d3bf
diff --git a/src/backend/distributed/metadata/node_metadata.c b/src/backend/distributed/metadata/node_metadata.c
index d93b133ea..d92205943 100644
--- a/src/backend/distributed/metadata/node_metadata.c
+++ b/src/backend/distributed/metadata/node_metadata.c
@@ -217,6 +217,9 @@ citus_set_coordinator_host(PG_FUNCTION_ARGS)
 		EnsureTransactionalMetadataSyncMode();
 	}
 
+	/* prevent concurrent modification */
+	LockRelationOid(DistNodeRelationId(), RowExclusiveLock);
+
 	bool isCoordinatorInMetadata = false;
 	WorkerNode *coordinatorNode = PrimaryNodeForGroup(COORDINATOR_GROUP_ID,
 													  &isCoordinatorInMetadata);