基本上，当我用./start-all.sh命令启动hadoop时，我遇到了一些问题。
我已经看过hadoop集群设置-java.net.connectexception:连接被拒绝
并且有0个datanode正在运行，并且在此操作中没有排除任何节点
当我跑的时候./start-all.sh

WARNING: Attempting to start all Apache Hadoop daemons as snagaraj in 10 
  seconds.
  WARNING: This is not a recommended production deployment configuration.
  WARNING: Use CTRL-C to abort.
  Starting namenodes on [localhost]
  pdsh@greg: localhost: ssh exited with exit code 1
  Starting datanodes
  Starting secondary namenodes [greg.bcmdc.bcm.edu]
  Starting resourcemanager
  Starting nodemanagers

当我运行一个使用hadoop/hdfs的python脚本时，我得到了一个错误

org.apache.hadoop.ipc.RemoteException(java.io.IOException): File 
  /user/data/...._COPYING_ could only be written to 0 of the 
  1 minReplication nodes. There are 0 datanode(s) running and 0 node(s) 
  are excluded in this operation.

我尝试过用hdfs namenode-format重新格式化namenode，但是没有帮助。
我的xml文件上的配置似乎是正确的，我到java\ U主页的路径也是正确的。我很乐意根据需要提供信息。