CDH起datanode服务时遇到的异常及解决方法

报错内容

WARN org.apache.hadoop.hdfs.server.datanode.DataNode: Invalid dfs.datanode.data.dir /opt/dfs/dn: 
ExitCodeException exitCode=1: chmod: changing permissions of `/opt/dfs/dn': Operation not permitted

    at org.apache.hadoop.util.Shell.runCommand(Shell.java:538)
    at org.apache.hadoop.util.Shell.run(Shell.java:455)
    at org.apache.hadoop.util.Shell$ShellCommandExecutor.execute(Shell.java:715)
    at org.apache.hadoop.util.Shell.execCommand(Shell.java:808)
    at org.apache.hadoop.util.Shell.execCommand(Shell.java:791)
    at org.apache.hadoop.fs.RawLocalFileSystem.setPermission(RawLocalFileSystem.java:656)
    at org.apache.hadoop.fs.FilterFileSystem.setPermission(FilterFileSystem.java:490)
    at org.apache.hadoop.util.DiskChecker.mkdirsWithExistsAndPermissionCheck(DiskChecker.java:140)
    at org.apache.hadoop.util.DiskChecker.checkDir(DiskChecker.java:156)
    at org.apache.hadoop.hdfs.server.datanode.DataNode$DataNodeDiskChecker.checkDir(DataNode.java:2239)
    at org.apache.hadoop.hdfs.server.datanode.DataNode.checkStorageLocations(DataNode.java:2281)
    at org.apache.hadoop.hdfs.server.datanode.DataNode.makeInstance(DataNode.java:2263)
    at org.apache.hadoop.hdfs.server.datanode.DataNode.instantiateDataNode(DataNode.java:2155)
    at org.apache.hadoop.hdfs.server.datanode.DataNode.createDataNode(DataNode.java:2202)
    at org.apache.hadoop.hdfs.server.datanode.DataNode.secureMain(DataNode.java:2378)
    at org.apache.hadoop.hdfs.server.datanode.DataNode.main(DataNode.java:2402)

异常原因 ：hdfs用户的权限不够

解决方法： sudo chown -R hdfs:hdfs /opt
打开权限即可。然后重启