HDFS Permission Denied: Why Root Cannot Write to the /user Directory

[#1]

when i use hdfs comands it display errors:

hadoop fs -mkdir /user/,,myfile,, or   "hadoop fs -put myfile.txt /user/,,/,,"  

hadoop will display"Permission denied: user=root, access=WRITE, inode="/user":hdfs:supergroup:dr,,,"and so on,why?who can help me?

[#2 · Accepted solution]

Hey,

The /user/ directory is owned by "hdfs" with 755 permissions. As a result only hdfs can write to that directory. Unlike unix/linux, hdfs is the superuser and not root. So you would need to do this:

sudo -u hdfs hadoop fs -mkdir /user/,,myfile,,
sudo -u hdfs hadoop fs -put myfile.txt /user/,,/,,

If you want to create a home directory for root so you can store files in his directory, do:

sudo -u hdfs hadoop fs -mkdir /user/root
sudo -u hdfs hadoop fs -chown root /user/root

Then as root you can do "hadoop fs -put file /user/root/".

Hope this helps.

Chris

[#3]

I had this issue too in Dev during our automated oozie sharelib creation process--which was essentially doing this:

oozie-setup sharelib create -fs hdfs://devhost:8020 -locallib /usr/lib/oozie/oozie-sharelib-yarn.tar.gz

The error I was seeing was:

org.apache.hadoop.security.AccessControlException: Permission denied: user=oozie, access=WRITE, inode="/user":hdfs:supergroup:drwxr-xr-x

It wasn't exactly clear to me at first as it seemed like a permissions error given the error above.

For me it was solved by changing the address that the service was listening on in /etc/hadoop/conf/core-sitse.xml. Mine was previously listening on "localhost:8020." (127.0.0.1)

So to be clear my fix was this:

<configuration>
<property>
<name>fs.defaultFS</name>
<value>hdfs://0.0.0.0:8020</value>
</property>

&& then bounce the service with hadoop-hdfs-namenode restart
optional: validate with netstat -tupln | grep '8020' 

Hope this helps someone else out.

-cmcc

[#4]

A quick update to this thread to advise of a new Community Knowledge Article on this subject.

How to resolve "Permission denied" errors in CDH

[#5]

thank u so much!!!!

[#6]

This is the solution.
export HADOOP_USER_NAME=hdfs

[#7]

thanks. its worked nicely

[#8]

thanks it solved the problem

[#9]

In cloudera manager, go to hdfs configuration under advanced and put the following code in HDFS Service Configuration Safety Valve:

<property>
<name>dfs.permissions</name>
<value>false</value>
</property>

[#10]

to be specific "HDFS Service Advanced Configuration Snippet (Safety Valve) for hdfs-site.xml"