How to disable the "read only mode" in hdfs web ui?

Question

I am a beginner in Hadoop. The questions are related to the Web UI of version Hadoop 2.8.3.

• How to disable/change the READ ONLY MODE on the WEB UI (http://localhost:50070).

I tried getting the info from the documentation, but could not figure out the configuration to change/disable the READ ONLY MODE.

• How to implement simple authentification (user/password).

In the documentation (https://hadoop.apache.org/docs/r2.8.3/hadoop-project-dist/hadoop-common/HttpAuthentication.html) there is some configuration, but I don't know how does it work.

I am not sure with the configuration. Therefore, I am looking for a simple explanation.

Answer 1

Safemode for the NameNode is essentially a read-only mode for the HDFS cluster

https://hadoop.apache.org/docs/r2.8.3/hadoop-project-dist/hadoop-hdfs/HdfsUserGuide.html#Safemode

You can try to leave it but without more information, your cluster is currently in a bad state, and you need to fix whatever the issue is (such as removing corrupt blocks) before it'll let you attempt to write to disk again.

How to implement simple authentification

Without Kerberos within Hadoop or some other proxy software in front of the Hadoop UI that adds Basic Auth, there is no password protected setup.