Hadoop: working file permissions

Hadoop provides following commands to work with file permissions.

         chgrp: Change group association of files

         chmod: Change the permissions of files

         chown: Change the owner of files

Each file/directory in HDFS is associated with a group or owner.

For files

         r permission is required to read the file,

         w permission is required to write or append to the file

For directories

r permission is required to list the contents of the directory

w permission is required to create or delete files or directories

x permission is required to access a child of the directory

In addition to read, write and execute permissions, there are 3 kinds of users owner, group, others for a file/directory in HDFS. We can set permissions for all three categories of users using the commands mentioned above. When a file or directory is created, its owner is the user identity of the client process, and its group is the group of the parent directory

chmod: Change the permissions of files.       

Change the permissions of files. With -R, make the change recursively through the directory structure.

Usage:

hadoop fs [generic options] -chmod [-R] <MODE[,MODE]... | OCTALMODE> PATH...

$ hadoop fs -ls /user/harikrishna_gurram/dir1/append.txt
-rw-r--r--   3 harikrishna_gurram w         20 2015-06-18 12:45 /user/harikrishna_gurram/dir1/append.txt
l$ 
l$ hadoop fs -chmod g+w /user/harikrishna_gurram/dir1/append.txt
l$ 
l$ hadoop fs -ls /user/harikrishna_gurram/dir1/append.txt
-rw-rw-r--   3 harikrishna_gurram w         20 2015-06-18 12:45 /user/harikrishna_gurram/dir1/append.txt

chgrp: Change group association of files

Change group association of files. The user must be the owner of files, or else a super-user.

Usage:

hadoop fs [generic options] -chgrp [-R] GROUP PATH...

$ hadoop fs -ls /user/harikrishna_gurram/dir1/append.txt
-rw-rw-r--   3 harikrishna_gurram w         20 2015-06-18 12:45 /user/harikrishna_gurram/dir1/append.txt
$ 
$ hadoop fs -chgrp group1 /user/harikrishna_gurram/dir1/append.txt
$ 
$ hadoop fs -ls /user/harikrishna_gurram/dir1/append.txt
-rw-rw-r--   3 harikrishna_gurram group1         20 2015-06-18 12:45 /user/harikrishna_gurram/dir1/append.txt

chown: Change owner of files

Change the owner of files. The user must be a super-user.

Usage

hadoop fs [generic options] -chown [-R] [OWNER][:[GROUP]] PATH...

$ hadoop fs -ls /user/harikrishna_gurram/dir1/append.txt
-rw-rw-r--   3 harikrishna_gurram group1         20 2015-06-18 12:45 /user/harikrishna_gurram/dir1/append.txt
$ 
$ hadoop fs -chown "Phalgun" /user/harikrishna_gurram/dir1/append.txt
$ 
$ hadoop fs -ls /user/harikrishna_gurram/dir1/append.txt
-rw-rw-r--   3 Phalgun group1         20 2015-06-18 12:45 /user/harikrishna_gurram/dir1/append.txt

Previous                                                 Next                                                 Home