Step 1: Set up a Kerberos Principal and keytab File

Each node running the httpFS service must have a keytab file (/opt/mapr/conf/mapr.keytab) and these two principals:

  • HTTP/<fully.qualified.domain.name>
  • mapr/<fully.qualified.domain.name>
Note: For complete instructions on generating a Kerberos principal and keytab file, see Configuring Kerberos User Authentication.

To check whether the keytab already exists, and if it contains the two necessary principals, run the klist command with the -k (keytab keys), -e (encryption type) and -t (timestamp) options:

$ klist -ket /opt/mapr/conf/mapr.keytab
The output from this command displays the following information:
  • KVNO (key version number)
  • Timestamp (the time the key was generated)
  • Principal names
  • Encryption types
If the keytab file does not exist, or does not contain both principals, generate them by following these steps:
  1. Generate a Kerberos principal for the mapr user. The principal is of the form mapr/<fully.qualified.domain.name>@<your-realm>.com, where <fully.qualified.domain.name> is unique for each httpFS node. In the following example, perfnode153.perf.lab@dev-maprtech.com is used for the <fully.qualified.domain.name>@<your-realm>.com.
    $ kadmin
    kadmin: addprinc -randkey mapr/perfnode153.perf.lab@dev-maprtech.com
  2. Generate a Kerberos principal for HTTP/<fully.qualified.domain.name>. This is required for Kerberos authentication of the httpFS server using HTTP SPNEGO.
    $ kadmin
    kadmin: addprinc -randkey HTTP/perfnode153.perf.lab@dev-maprtech.com
  3. If the current node does not already have a keytab file created for another service, create one and name it mapr.keytab. Note that each node references the same keytab file (usually located at /opt/mapr/conf/mapr.keytab), and each keytab file can have multiple principals.
    kadmin: ktadd -k /opt/mapr/conf/mapr.keytab mapr/perfnode153.perf.lab
  4. Change the owner of the keytab file from the root user (the default) to the mapr user.
    $ chown mapr:mapr /opt/mapr/conf/mapr.keytab
  5. Set read-only permissions on the mapr.keytabfile.
    $ chmod 600 mapr:mapr /opt/mapr/conf/mapr.keytab