diff --git a/src/cm_server/cms_global_params.cpp b/src/cm_server/cms_global_params.cpp
index dd7651c5ce79c70bd44c1b78cf98eff2ed97c63c..088ed1f22553edaa3860688b848a49e7f856500e 100644
--- a/src/cm_server/cms_global_params.cpp
+++ b/src/cm_server/cms_global_params.cpp
@@ -502,6 +502,7 @@ static void SendKillForAgentFault(uint32 groupIdx)
         }
         if (instRep->cma_kill_instance_timeout == 1 && instRole[i].role == INSTANCE_ROLE_PRIMARY &&
             dnRep[i].local_status.local_role == INSTANCE_ROLE_UNKNOWN) {
+            write_runlog(KEY_EVENT_KILL_INSTANCE, "will kill instance %u.\n", instRole[i].instanceId);
             kill_instance_for_agent_fault(instRole[i].node, instRole[i].instanceId, INSTANCE_TYPE_DATANODE);
             instRep->cma_kill_instance_timeout = 0;
         }
diff --git a/src/include/cm/cm_elog.h b/src/include/cm/cm_elog.h
index 22a948abea21a95ec7aa00803d3fe4034bdbf110..9a67637d53761789142c14cd1c201876b02be634 100644
--- a/src/include/cm/cm_elog.h
+++ b/src/include/cm/cm_elog.h
@@ -50,6 +50,7 @@ typedef enum KeyEventTypeEn {
     KEY_EVENT_REFRESH_OBS_DELETE_TEXT = 17,
     KEY_EVENT_DROP_CN_OBS_XLOG = 18,
     KEY_EVENT_RES_ARBITRATE = 19,
+    KEY_EVENT_KILL_INSTANCE = 20,
     KEY_EVENT_TYPE_CEIL, // new event types should be added before this.
 } KeyEventType;