Set up WebHDFS on a secure cluster

Setting up WebHDFS on a secure cluster requires you to update certain properties on hdfs-site.xml, create an HTTP service user principal, create a keytab for the principal, and verify the association of the principal and keytab with the correct HTTP service.

Create an HTTP service user principal.
```
kadmin: addprinc -randkey HTTP/$<Fully_Qualified_Domain_Name>@$<Realm_Name>.COM
```
where:
- Fully_Qualified_Domain_Name: Host where the NameNode is deployed.
- Realm_Name: Name of your Kerberos realm.

Create a keytab file for the HTTP principal.

kadmin: xst -norandkey -k /etc/security/spnego.service.keytab HTTP/$<Fully_Qualified_Domain_Name>

Verify that the keytab file and the principal are associated with the correct service.
```
klist –k -t /etc/security/spnego.service.keytab
```

Add the dfs.web.authentication.kerberos.principal and dfs.web.authentication.kerberos.keytab properties to hdfs-site.xml.

<property>
  <name>dfs.web.authentication.kerberos.principal</name>
  <value>HTTP/$<Fully_Qualified_Domain_Name>@$<Realm_Name>.COM</value>
</property>
<property>
  <name>dfs.web.authentication.kerberos.keytab</name>
  <value>/etc/security/spnego.service.keytab</value>
</property>

Restart the NameNode and the DataNodes.