Adding Kerberos service principals for each node in a cluster

Steps for adding Kerberos principals.

1. On each node, note the fully qualified domain name (FQDN) of the machine:

   hostname --fqdn

   node1.example.com

2. On the Kerberos Key Distribution Center (KDC), run the kadmin command:

   kadmin -p admin_user/admin
   addprinc -randkey dse/FQDN
   addprinc -randkey HTTP/FQDN
   quit

   where

   Parameter	Description
   addprinc	The add_principal command requires the add administrative privilege and creates the new principal.
   dse	The service name is dse.
   FQDN	The fully qualified domain name of the host where DataStax Enterprise is running.
   -randkey	Sets the key of the principal to a random value.

   Example:

   kadmin -p admin_user/admin
   addprinc -randkey dse/node1.example.com
   addprinc -randkey HTTP/node1.example.com
   addprinc -randkey dse/node2.example.com
   addprinc -randkey HTTP/node2.example.com

3. Optional: Verify that the principals have been added by running the listprincs command within kadmin:

   listprincs

   HTTP/node1.example.com@EXAMPLE.COM
   HTTP/node2.example.com@EXAMPLE.COM
   dse/node1.example.com@EXAMPLE.COM
   dse/node2.example.com@EXAMPLE.COM
   kadmin/admin@EXAMPLE.COM

   where node*.example.com is the FQDN and EXAMPLE.COM is your Kerberos realm, which must be all uppercase.
4. Create a keytab file for each node with the principals keys for that node:

   kadmin -p admin_user/admin
   ktadd -k dse.keytab dse/FQDN
   ktadd -k dse.keytab HTTP/FQDN
   quit

   where ktadd -k creates or appends a keytab for the dse and HTTP principals.

   Example:

   kadmin -p admin_user/admin
   ktadd -k /tmp/node1.keytab dse/node1.example.com
   ktadd -k /tmp/node1.keytab HTTP/node1.example.com
   ktadd -k /tmp/node2.keytab dse/node2.example.com
   ktadd -k /tmp/node2.keytab HTTP/node2.example.com

5. Optional: Use the klist command to view your principals and keytabs:
   Node1:

   sudo klist -e -kt /var/tmp/dse.keytab

   
   Keytab name: FILE:/tmp/dse.keytab
   KVNO Timestamp        Principal
   ---- ---------------- ----------------------------------------------
   2    14/02/16 22:03   HTTP/node1FQDN@YOUR_REALM (des3-cbc-sha1)
   2    14/02/16 22:03   HTTP/node1FQDN@YOUR_REALM (arcfour-hmac)
   2    14/02/16 22:03   HTTP/node1FQDN@YOUR_REALM (des-hmac-sha1)
   2    14/02/16 22:03   HTTP/node1FQDN@YOUR_REALM (des-cbc-md5)
   2    14/02/16 22:03   dse/node1FQDN@YOUR_REALM (des3-cbc-sha1)
   2    14/02/16 22:03   dse/node1FQDN@YOUR_REALM (arcfour-hmac)
   2    14/02/16 22:03   dse/node1FQDN@YOUR_REALM (des-hmac-sha1)
   2    14/02/16 22:03   dse/node1FQDN@YOUR_REALM (des-cbc-md5)

   where: -e displays the encryption type and -kt displays the keytab file and its timestamp.
6. Copy the node-specific keytab files from the KDC machine to the nodes:

   $ scp /tmp/node1.keytab dse@node1.FQDN:/etc/dse/
   $ scp /tmp/node2.keytab dse@node2.FQDN:/etc/dse/

7. On each node, change the name of the keytab file to dse.keytab.

   Make the file names identical across all the nodes to ensure that the entry in each node's dse.yaml is the same.

   Example:

   hostname --fqdn
   node1.example.com
   $ mv /etc/dse/node1.keytab /etc/dse/dse.keytab

8. Change the permissions on dse.keytab so that only the dse_user user can read and write to the keytab file. For example:

   sudo chown cassandra:cassandra /etc/dse/dse.keytab
   $ sudo chmod 600 /etc/dse/dse.keytab

   The location of the dse.yaml file depends on the type of installation:

   Installer-Services	/etc/dse/dse.yaml
   Package installations	/etc/dse/dse.yaml
   Installer-No Services	install_location/resources/dse/conf/dse.yaml
   Tarball installations	install_location/resources/dse/conf/dse.yaml

9. To use a Kerberos non-default REALM with Hadoop, you must specify mapping rules to map the Kerberos principal to the local UNIX user name. Add this configuration key to the resources/hadoop/conf/dse-core.xml file:

   <property>
       <name>hadoop.security.auth_to_local</name>
         <value>
         RULE:[1:$1](.*)s/.*/\${username}/
         DEFAULT
         </value>
     </property>

   The default location of the dse-core.xml Hadoop configuration file depends on the type of installation:

   Installer-Services and Package installations	/etc/dse/hadoop/conf
   Installer-No Services and Tarball installations	install_location/resources/hadoop/conf/