fix force kill for elastic (#34488)

* fix force kill for elastic

python/paddle/distributed/fleet/elastic.py

@@ -133,6 +133,7 @@ class ElasticManager(object):
         self.stopped = False
 
         self.sigint = 0
+        self.need_sync = False
 
         if not server or ':' not in server or not name or not np:
             logger.info(
@@ -177,6 +178,7 @@ class ElasticManager(object):
                 logger.info('register host again {}'.format(self.host))
 
                 self.etcd.put(self.host_path, six.b(self.host))
+                self.need_sync = True
 
         host_watch = self.etcd.add_watch_callback(self.host_path,
                                                   host_call_back)
@@ -254,6 +256,7 @@ class ElasticManager(object):
         return int(self.etcd.get(self.prefix)[0]) == 1
 
     def _match(self):
+
         self.hosts = [
             six.ensure_str(i[0]) for i in self.etcd.get_prefix(self.node_prefix)
         ]
@@ -307,7 +310,8 @@ class ElasticManager(object):
                                                                self.hosts))
 
             idx += 1
-            time.sleep(3)
+            time.sleep(2)
+
         return
 
     def run(self, launcher):
@@ -319,6 +323,9 @@ class ElasticManager(object):
 
     def watch(self):
 
+        if self.need_sync:
+            self.need_sync = False
+
         while not self.stopped:
             ret = self.launcher.watch()
 
@@ -334,7 +341,7 @@ class ElasticManager(object):
                 else:
                     return ElasticStatus.ERROR
 
-            if not self._completed() and not self._match():
+            if not self._completed() and (not self._match() or self.need_sync):
                 self.launcher.stop()
                 return ElasticStatus.HOLD