Job tracker is not starting up - hadoop

Question

I am installing CDH4.6.0 with the help of this site I am running start-all.sh to start services.
/etc/init.d/hadoop-hdfs-namenode start
/etc/init.d/hadoop-hdfs-datanode start
/etc/init.d/hadoop-hdfs-secondarynamenode start
/etc/init.d/hadoop-0.20-mapreduce-jobtracker start
/etc/init.d/hadoop-0.20-mapreduce-tasktracker start
bin/bash [to start bash prompt after starting services]
After executing these instructions as a part of docker file, like
CMD ["start-all.sh"]
It starts all the services
When i jps it, i can see only
jps
Namenode
Datanode
Secondary Namenode
Tasktracker
But job tracker is not yet started. log is as follows
2015-01-23 07:26:46,706 INFO org.apache.hadoop.metrics.jvm.JvmMetrics:
Initializing JVM Metrics with processName=JobTracker, sessionId=
2015-01-23 07:26:46,735 INFO org.apache.hadoop.mapred.JobTracker:
JobTracker up at: 8021
2015-01-23 07:26:46,735 INFO org.apache.hadoop.mapred.JobTracker:
JobTracker webserver: 50030
2015-01-23 07:26:47,725 INFO org.apache.hadoop.mapred.JobTracker:
Creating the system directory
2015-01-23 07:26:47,750 WARN org.apache.hadoop.mapred.JobTracker: Failed
to operate on mapred.system.dir (hdfs://localhost:8020/var/lib/hadoop-
hdfs/cache/mapred/mapred/system) because of permissions.
2015-01-23 07:26:47,750 WARN org.apache.hadoop.mapred.JobTracker: This
directory should be owned by the user 'mapred (auth:SIMPLE)'
2015-01-23 07:26:47,751 WARN org.apache.hadoop.mapred.JobTracker: Bailing out ...
org.apache.hadoop.security.AccessControlException: Permission denied: user=mapred, access=WRITE, inode="/":hdfs:supergroup:drwxr-xr-x
But when i again start it from bash prompt, it works. Why so? Any suggestions?
I can see it from the log. Job tracker is starting at port 8020 and why is it trying to operate at port 8020? Is it a problem? If so, how to tackle it?

Answer 1

Seems like the mapred user doesn't have privilege to write files/directories inside the HDFS root directory.
Switch to hdfs user and assign necessary privilege to mapred user before starting mapreduce service.
sudo -su hdfs ;
hadoop fs -chmod 777 /
/etc/init.d/hadoop-0.20-mapreduce-jobtracker stop; /etc/init.d/hadoop-0.20-mapreduce-jobtracker start