Basic permissions error in MR2

Question

A recent build of MR2 basic examples were failing, i.e. running the pi example, in a psuedo distributed MR2 HDFS cluster, with the following error:

13/07/06 21:20:47 ERROR security.UserGroupInformation: PriviledgedActionException as:root (auth:SIMPLE) cause:org.apache.hadoop.security.AccessControlException: Permission denied: user=root, access=EXECUTE, inode="/tmp/hadoop-yarn/staging":mapred:mapred:drwxrwx---

Why could this be happening ?

Answer 1

Add yarn.app.mapreduce.am.staging-dir on your mapred-site.xml like this:

<property>
  <name>yarn.app.mapreduce.am.staging-dir</name>
  <value>/user</value>
</property>

This configuration presumes that the user account, in your case root, has its home directory /user/root on the HDFS, and the staging directory will be created as /user/root/.staging where the user account already has the right permissions.

For more information, check out "Step 4: Configure the Staging Directory" on the followig link.

• http://www.cloudera.com/content/cloudera/en/documentation/core/v5-2-x/topics/cdh_ig_yarn_cluster_deploy.html