hive執行sql後一直處在ACCEPTED: waiting for AM container to be allocated, launched and register with RM.狀態，並且報錯返回FAILED: Execution Error, return code 2 from org.apache.hadoop.hive.ql.exec.mr.MapRedTask
查看hadoop的8088端口網頁時可以看到錯誤日誌是在datanode裏打印出來的，並且是
java.net.ConnectException: Call From localhost/127.0.0.1 to localhost:56908 failed on connection exceptjava.net.ConnectException: Connection refused; For more details see: http://wiki.apache.org/hadoop/ConnectionRefused at sun.reflect.NativeConstructorAccessorImpl.newInstance0(Native Method) at sun.reflect.NativeConstructorAccessorImpl.newInstance(NativeConstructorAccessorImpl.java:57) at sun.reflect.DelegatingConstructorAccessorImpl.newInstance(DelegatingConstructorAccessorImpl.java:45) at java.lang.reflect.Constructor.newInstance(Constructor.java:526) at org.apache.hadoop.net.NetUtils.wrapWithMessage(NetUtils.java:791) at org.apache.hadoop.net.NetUtils.wrapException(NetUtils.java:731) at org.apache.hadoop.ipc.Client.call(Client.java:1473) at org.apache.hadoop.ipc.Client.call(Client.java:1400) at org.apache.hadoop.ipc.ProtobufRpcEngine$Invoker.invoke(ProtobufRpcEngine.java:232) at com.sun.proxy.$Proxy14.sendHeartbeat(Unknown Source) at org.apache.hadoop.hdfs.protocolPB.DatanodeProtocolClientSideTranslatorPB.sendHeartbeat(DatanodeProtocolClientSideTranslatorPB.java:139) at org.apache.hadoop.hdfs.server.datanode.BPServiceActor.sendHeartBeat(BPServiceActor.java:617) at org.apache.hadoop.hdfs.server.datanode.BPServiceActor.offerService(BPServiceActor.java:715) at org.apache.hadoop.hdfs.server.datanode.BPServiceActor.run(BPServiceActor.java:889) at java.lang.Thread.run(Thread.java:745) Caused by: java.net.ConnectException: Connection refused at sun.nio.ch.SocketChannelImpl.checkConnect(Native Method) at sun.nio.ch.SocketChannelImpl.finishConnect(SocketChannelImpl.java:739) at org.apache.hadoop.net.SocketIOWithTimeout.connect(SocketIOWithTimeout.java:206) at org.apache.hadoop.net.NetUtils.connect(NetUtils.java:530) at org.apache.hadoop.net.NetUtils.connect(NetUtils.java:494) at org.apache.hadoop.ipc.Client$Connection.setupConnection(Client.java:608) at org.apache.hadoop.ipc.Client$Connection.setupIOstreams(Client.java:706) at org.apache.hadoop.ipc.Client$Connection.access$2800(Client.java:369) at org.apache.hadoop.ipc.Client.getConnection(Client.java:1522) at org.apache.hadoop.ipc.Client.call(Client.java:1439) ... 8 more
這種情況可能是配置的hostname在/etc/hosts裏找不到對應的ip
但是另外一種情況就是在執行hive sql的機器上沒有啓動datanode，這時候任務找的還是localhost:9000服務對應的hdfs,找不到就會報錯，但是任務卻一直在等待。