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From Arpit Gupta <ar...@hortonworks.com>
Subject Re: issue with permissions of mapred.system.dir
Date Wed, 10 Oct 2012 00:22:52 GMT
what is your "mapreduce.jobtracker.staging.root.dir" set to. This is a directory that needs
to be writable by the user and is is recommended to be set to "/user" so it writes in appropriate
users home directory.

--
Arpit Gupta
Hortonworks Inc.
http://hortonworks.com/

On Oct 9, 2012, at 4:44 PM, "Goldstone, Robin J." <goldstone1@llnl.gov> wrote:

> I am bringing up a Hadoop cluster for the first time (but am an experienced sysadmin
with lots of cluster experience) and running into an issue with permissions on mapred.system.dir.
  It has generally been a chore to figure out all the various directories that need to be
created to get Hadoop working, some on the local FS, others within HDFS, getting the right
ownership and permissions, etc..  I think I am mostly there but can't seem to get past my
current issue with mapred.system.dir.
> 
> Some general info first:
> OS: RHEL6
> Hadoop version: hadoop-1.0.3-1.x86_64
> 
> 20 node cluster configured as follows
> 1 node as primary namenode
> 1 node as secondary namenode + job tracker
> 18 nodes as datanode + tasktracker
> 
> I have HDFS up and running and have the following in mapred-site.xml:
> <property>
>   <name>mapred.system.dir</name>
>   <value>hdfs://hadoop1/mapred</value>
>   <description>Shared data for JT - this must be in HDFS</description>
> </property>
> 
> I have created this directory in HDFS, owner mapred:hadoop, permissions 700 which seems
to be the most common recommendation amongst multiple, often conflicting articles about how
to set up Hadoop.  Here is the top level of my filesystem:
> hyperion-hdp4@hdfs:hadoop fs -ls /
> Found 3 items
> drwx------   - mapred hadoop          0 2012-10-09 12:58 /mapred
> drwxrwxrwx   - hdfs   hadoop          0 2012-10-09 13:00 /tmp
> drwxr-xr-x   - hdfs   hadoop          0 2012-10-09 12:51 /user
> 
> Note, it doesn't seem to really matter what permissions I set on /mapred since when the
Jobtracker starts up it changes them to 700.  
> 
> However, when I try to run the hadoop example teragen program as a "regular" user I am
getting this error:
> hyperion-hdp4@robing:hadoop jar /usr/share/hadoop/hadoop-examples*.jar teragen -D dfs.block.size=536870912
10000000000 /user/robing/terasort-input
> Generating 10000000000 using 2 maps with step of 5000000000
> 12/10/09 16:27:02 INFO mapred.JobClient: Running job: job_201210072045_0003
> 12/10/09 16:27:03 INFO mapred.JobClient:  map 0% reduce 0%
> 12/10/09 16:27:03 INFO mapred.JobClient: Job complete: job_201210072045_0003
> 12/10/09 16:27:03 INFO mapred.JobClient: Counters: 0
> 12/10/09 16:27:03 INFO mapred.JobClient: Job Failed: Job initialization failed:
> org.apache.hadoop.security.AccessControlException: org.apache.hadoop.security.AccessControlException:
Permission denied: user=robing, access=EXECUTE, inode="mapred":mapred:hadoop:rwx------
> at sun.reflect.NativeConstructorAccessorImpl.newInstance0(Native Method)
> at sun.reflect.NativeConstructorAccessorImpl.newInstance(NativeConstructorAccessorImpl.java:39)
> at sun.reflect.DelegatingConstructorAccessorImpl.newInstance(DelegatingConstructorAccessorImpl.java:27)
> at java.lang.reflect.Constructor.newInstance(Constructor.java:513)
> at org.apache.hadoop.ipc.RemoteException.instantiateException(RemoteException.java:95)
> at org.apache.hadoop.ipc.RemoteException.unwrapRemoteException(RemoteException.java:57)
> at org.apache.hadoop.hdfs.DFSClient$DFSOutputStream.<init>(DFSClient.java:3251)
> at org.apache.hadoop.hdfs.DFSClient.create(DFSClient.java:713)
> at org.apache.hadoop.hdfs.DistributedFileSystem.create(DistributedFileSystem.java:182)
> at org.apache.hadoop.fs.FileSystem.create(FileSystem.java:555)
> at org.apache.hadoop.fs.FileSystem.create(FileSystem.java:536)
> at org.apache.hadoop.fs.FileSystem.create(FileSystem.java:443)
> at org.apache.hadoop.fs.FileSystem.create(FileSystem.java:435)
> at org.apache.hadoop.security.Credentials.writeTokenStorageFile(Credentials.java:169)
> at org.apache.hadoop.mapred.JobInProgress.generateAndStoreTokens(JobInProgress.java:3537)
> at org.apache.hadoop.mapred.JobInProgress.initTasks(JobInProgress.java:696)
> at org.apache.hadoop.mapred.JobTracker.initJob(JobTracker.java:4207)
> at org.apache.hadoop.mapred.FairScheduler$JobInitializer$InitJob.run(FairScheduler.java:291)
> at java.util.concurrent.ThreadPoolExecutor$Worker.runTask(ThreadPoolExecutor.java:886)
> at java.util.concurrent.ThreadPoolExecutor$Worker.run(ThreadPoolExecutor.java:908)
> at java.lang.Thread.run(Thread.java:662)
> <rest of stack trace omitted>
> 
> This seems to be saying that is trying to write to the HDFS /mapred filesystem as me
(robing) rather than as mapred, the username under which the jobtracker and tasktracker run.
> 
> To verify this is what is happening, I manually changed the permissions on /mapred from
700 to 755 since it claims to want execute access:
> hyperion-hdp4@mapred:hadoop fs -chmod 755 /mapred
> hyperion-hdp4@mapred:hadoop fs -ls /
> Found 3 items
> drwxr-xr-x   - mapred hadoop          0 2012-10-09 12:58 /mapred
> drwxrwxrwx   - hdfs   hadoop          0 2012-10-09 13:00 /tmp
> drwxr-xr-x   - hdfs   hadoop          0 2012-10-09 12:51 /user
> hyperion-hdp4@mapred:
> 
> Now I try running again and it fails again, this time complaining it wants write access
to /mapred:
> hyperion-hdp4@robing:hadoop jar /usr/share/hadoop/hadoop-examples*.jar teragen -D dfs.block.size=536870912
10000000000 /user/robing/terasort-input
> Generating 10000000000 using 2 maps with step of 5000000000
> 12/10/09 16:31:29 INFO mapred.JobClient: Running job: job_201210072045_0005
> 12/10/09 16:31:30 INFO mapred.JobClient:  map 0% reduce 0%
> 12/10/09 16:31:30 INFO mapred.JobClient: Job complete: job_201210072045_0005
> 12/10/09 16:31:30 INFO mapred.JobClient: Counters: 0
> 12/10/09 16:31:30 INFO mapred.JobClient: Job Failed: Job initialization failed:
> org.apache.hadoop.security.AccessControlException: org.apache.hadoop.security.AccessControlException:
Permission denied: user=robing, access=WRITE, inode="mapred":mapred:hadoop:rwxr-xr-x
> 
> So I changed the permissions on /mapred to 777:
> hyperion-hdp4@mapred:hadoop fs -chmod 777 /mapred
> hyperion-hdp4@mapred:hadoop fs -ls /
> Found 3 items
> drwxrwxrwx   - mapred hadoop          0 2012-10-09 12:58 /mapred
> drwxrwxrwx   - hdfs   hadoop          0 2012-10-09 13:00 /tmp
> drwxr-xr-x   - hdfs   hadoop          0 2012-10-09 12:51 /user
> hyperion-hdp4@mapred:
> 
> And then I run again and this time it works.
> yperion-hdp4@robing:hadoop jar /usr/share/hadoop/hadoop-examples*.jar teragen -D dfs.block.size=536870912
10000000000 /user/robing/terasort-input
> Generating 10000000000 using 2 maps with step of 5000000000
> 12/10/09 16:33:02 INFO mapred.JobClient: Running job: job_201210072045_0006
> 12/10/09 16:33:03 INFO mapred.JobClient:  map 0% reduce 0%
> 12/10/09 16:34:34 INFO mapred.JobClient:  map 1% reduce 0%
> 12/10/09 16:35:52 INFO mapred.JobClient:  map 2% reduce 0%
> etc…
> 
> And indeed I can see that there is stuff written to /mapred under my userid:
> # hyperion-hdp4 /root > hadoop fs -ls /mapred
> Found 2 items
> drwxrwxrwx   - robing hadoop          0 2012-10-09 16:33 /mapred/job_201210072045_0006
> -rw-------   2 mapred hadoop          4 2012-10-09 12:58 /mapred/jobtracker.info
> 
> However,man ally setting the permissions to 777 is not a workable solution since any
time I restart the jobtracker, it is setting the permissions on /mapred back to 700.  
>  hyperion-hdp3 /root > hadoop fs -ls /
> Found 3 items
> drwxrwxrwx   - mapred hadoop          0 2012-10-09 16:33 /mapred
> drwxrwxrwx   - hdfs   hadoop          0 2012-10-09 13:00 /tmp
> drwxr-xr-x   - hdfs   hadoop          0 2012-10-09 12:51 /user
> # hyperion-hdp3 /root > /etc/init.d/hadoop-jobtracker restart
> Stopping Hadoop jobtracker daemon (hadoop-jobtracker): stopping jobtracker
>                                                            [  OK  ]
> Starting Hadoop jobtracker daemon (hadoop-jobtracker): starting jobtracker, logging to
/var/log/hadoop/mapred/hadoop-mapred-jobtracker-hyperion-hdp3.out
>                                                            [  OK  ]
> # hyperion-hdp3 /root > hadoop fs -ls /
> Found 3 items
> drwx------   - mapred hadoop          0 2012-10-09 16:38 /mapred
> drwxrwxrwx   - hdfs   hadoop          0 2012-10-09 13:00 /tmp
> drwxr-xr-x   - hdfs   hadoop          0 2012-10-09 12:51 /user
> # hyperion-hdp3 /root > 
> 
> So my questions are:
> What are the right permissions on mapred.system.dir?
> If not 700, how do I get the job tracker to stop changing them to 700?
> If 700 is correct, then what am I doing wrong in my attempt to run the example teragen
program?
> 
> Thank you in advance.
> Robin Goldstone, LLNL
> 


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