Created on 08-04-2014 01:12 PM - edited 08-04-2014 01:12 PM
The error indicates that mapreduce wants to be able to write to /. you have the owner as hdfs with rwx, you have groups with r-x, and others set to r-x. Since you added mapred to the groups membership earlier by adding it to supergroup and making supergroup the group for / it is the group level permissions that we will need to modify.
To get it working you can do the following:
sudo -u hdfs hdfs dfs -chmod 775 /
this will change the permissions on / to drwxrwxr-x
as for why mapreduce is trying to write to / it may be that it's trying to create /user and /tmp that you have defined as the user space and the temporary space. if you don't have those directories you could instead do the following:
sudo -u hdfs hdfs dfs -mkdir /user
sudo -u hdfs hdfs dfs -chown mapred:mapred /user
sudo -u hdfs hdfs dfs -mkdir /tmp
sudo -u hdfs hdfs dfs -chown mapred:mapred /tmp