我是hadoop spark的noob。我已经设置了一个hadoop/spark集群（1个namenode，2个datanode）。现在我尝试在hdfs中使用scoop从db（mysql）导入数据，但总是失败

16/07/27 16:50:04 INFO mapreduce.Job: Running job: job_1469629483256_0004
16/07/27 16:50:11 INFO mapreduce.Job: Job job_1469629483256_0004 running in uber mode : false
16/07/27 16:50:11 INFO mapreduce.Job:  map 0% reduce 0%
16/07/27 16:50:13 INFO ipc.Client: Retrying connect to server: datanode1_hostname/172.31.58.123:59676. Already tried 0 time(s); retry policy is RetryUpToMaximumCountWithFixedSleep(maxRetries=3, sleepTime=1000 MILLISECONDS)
16/07/27 16:50:14 INFO ipc.Client: Retrying connect to server: datanode1_hostname/172.31.58.123:59676. Already tried 1 time(s); retry policy is RetryUpToMaximumCountWithFixedSleep(maxRetries=3, sleepTime=1000 MILLISECONDS)
16/07/27 16:50:15 INFO ipc.Client: Retrying connect to server: datanode1_hostname/172.31.58.123:59676. Already tried 2 time(s); retry policy is RetryUpToMaximumCountWithFixedSleep(maxRetries=3, sleepTime=1000 MILLISECONDS)
16/07/27 16:50:18 INFO mapreduce.Job: Job job_1469629483256_0004 failed with state FAILED due to: Application application_1469629483256_0004 failed 2 times due to AM Container for appattempt_1469629483256_0004_000002 exited with  exitCode: 255
For more detailed output, check application tracking page:http://ip-172-31-55-182.ec2.internal:8088/cluster/app/application_1469629483256_0004Then, click on links to logs of each attempt.
Diagnostics: Exception from container-launch.
Container id: container_1469629483256_0004_02_000001
Exit code: 255
Stack trace: ExitCodeException exitCode=255: 
        at org.apache.hadoop.util.Shell.runCommand(Shell.java:545)
        at org.apache.hadoop.util.Shell.run(Shell.java:456)
        at org.apache.hadoop.util.Shell$ShellCommandExecutor.execute(Shell.java:722)
        at org.apache.hadoop.yarn.server.nodemanager.DefaultContainerExecutor.launchContainer(DefaultContainerExecutor.java:212)
        at org.apache.hadoop.yarn.server.nodemanager.containermanager.launcher.ContainerLaunch.call(ContainerLaunch.java:302)
        at org.apache.hadoop.yarn.server.nodemanager.containermanager.launcher.ContainerLaunch.call(ContainerLaunch.java:82)
        at java.util.concurrent.FutureTask.run(FutureTask.java:266)
        at java.util.concurrent.ThreadPoolExecutor.runWorker(ThreadPoolExecutor.java:1142)
        at java.util.concurrent.ThreadPoolExecutor$Worker.run(ThreadPoolExecutor.java:617)
        at java.lang.Thread.run(Thread.java:745)

Container exited with a non-zero exit code 255
Failing this attempt. Failing the application.
16/07/27 16:50:18 INFO mapreduce.Job: Counters: 0
16/07/27 16:50:18 WARN mapreduce.Counters: Group FileSystemCounters is deprecated. Use org.apache.hadoop.mapreduce.FileSystemCounter instead
16/07/27 16:50:18 INFO mapreduce.ImportJobBase: Transferred 0 bytes in 16.2369 seconds (0 bytes/sec)
16/07/27 16:50:18 WARN mapreduce.Counters: Group org.apache.hadoop.mapred.Task$Counter is deprecated. Use org.apache.hadoop.mapreduce.TaskCounter instead
16/07/27 16:50:18 INFO mapreduce.ImportJobBase: Retrieved 0 records.
16/07/27 16:50:18 ERROR tool.ImportTool: Error during import: Import job failed!

我可以手动写入hdfs：

hdfs dfs -put <local file path> <hdfs path>

但当我运行scoop import命令时

sqoop import --connect jdbc:mysql://<host>/<db_name> --username <USERNAME> --password <PASSWORD> --table <TABLE_NAME> --enclosed-by '\"' --fields-terminated-by , --escaped-by \\ -m 1 --target-dir <hdfs location>

谁能告诉我我做错了什么吗
这是我已经尝试过的事情的清单
关闭群集，格式化hdfs，然后重新启动群集（没有帮助）
确保hdfs未处于安全模式
所有节点的 /etc/hosts ```
127.0.0.1 localhost
172.31.55.182 namenode_hostname
172.31.58.123 datanode1_hostname
172.31.58.122 datanode2_hostname

The following lines are desirable for IPv6 capable hosts

::1 ip6-localhost ip6-loopback
fe00::0 ip6-localnet
ff00::0 ip6-mcastprefix
ff02::1 ip6-allnodes
ff02::2 ip6-allrouters
ff02::3 ip6-allhosts

配置文件：
所有节点：$hadoop\u conf\u dir/core-site.xml：