在包裹分发期间，我发现我的节点没有取得进展。看着日志，这就是他抱怨的：
[18/Jun/2015 11:16:22 +0000] 16658 MainThread agent ERROR Heartbeating to master.adastragrp.com:7182 failed.
Traceback (most recent call last):
File "/usr/lib64/cmf/agent/src/cmf/agent.py", line 980, in send_heartbeat
response = self.requestor.request('heartbeat', dict(request=heartbeat))
File "/usr/lib64/cmf/agent/build/env/lib/python2.6/site-packages/avro-1.6.3-py2.6.egg/avro/ipc.py", line 139, in request
return self.issue_request(call_request, message_name, request_datum)
File "/usr/lib64/cmf/agent/build/env/lib/python2.6/site-packages/avro-1.6.3-py2.6.egg/avro/ipc.py", line 255, in issue_request
return self.read_call_response(message_name, buffer_decoder)
File "/usr/lib64/cmf/agent/build/env/lib/python2.6/site-packages/avro-1.6.3-py2.6.egg/avro/ipc.py", line 235, in read_call_response
raise self.read_error(writers_schema, readers_schema, decoder)
File "/usr/lib64/cmf/agent/build/env/lib/python2.6/site-packages/avro-1.6.3-py2.6.egg/avro/ipc.py", line 244, in read_error
return AvroRemoteException(datum_reader.read(decoder))
File "/usr/lib64/cmf/agent/build/env/lib/python2.6/site-packages/avro-1.6.3-py2.6.egg/avro/io.py", line 444, in read
return self.read_data(self.writers_schema, self.readers_schema, decoder)
File "/usr/lib64/cmf/agent/build/env/lib/python2.6/site-packages/avro-1.6.3-py2.6.egg/avro/io.py", line 448, in read_data
if not DatumReader.match_schemas(writers_schema, readers_schema):
File "/usr/lib64/cmf/agent/build/env/lib/python2.6/site-packages/avro-1.6.3-py2.6.egg/avro/io.py", line 379, in match_schemas
w_type = writers_schema.type
AttributeError: 'NoneType' object has no attribute 'type'
请注意，此节点与cloudera管理器位于同一台计算机上。没有防火墙正在运行。 WebUI显示代理实际上每隔几秒发送一次心跳。这里出了什么问题？