SELECT result from  run_command_on_all_nodes('ALTER SYSTEM SET citus.enable_ddl_propagation TO ON');
    result
---------------------------------------------------------------------
 ALTER SYSTEM
 ALTER SYSTEM
 ALTER SYSTEM
(3 rows)

SELECT result from  run_command_on_all_nodes('SELECT pg_reload_conf()');
 result
---------------------------------------------------------------------
 t
 t
 t
(3 rows)