When we have previously shown listings of files, we have seen user and group names for them. However, we have not really explored what that means. Let's do so.
Create a test text file in the Hadoop user's home directory.
$ echo "I can read this!" > security-test.txt $ hadoop fs -put security-test.txt security-test.txt
Change the permissions on the file to be accessible only by the owner.
$ hadoop fs -chmod 700 security-test.txt $ hadoop fs -ls
The output of the preceding command can be shown in the following screenshot:
Confirm you can still read the file.
$ hadoop fs -cat security-test.txtYou'll see the following line on the screen:
I can read this!Connect to another node in the cluster and try to read the file from there.
$ ssh node2 $ hadoop fs -cat security-test.txt
You'll see the following line on the screen:
I can read this!Log out from the other node.
$ exitCreate a home directory for another user and give them ownership...