Mine is identical, except that it has a few lines setting encryption types:
default_tkt_enctypes = rc4-hmac des3-cbc-sha1 des-cbc-crc des-cbc-md5
default_tgs_enctypes = rc4-hmac des3-cbc-sha1 des-cbc-crc des-cbc-md5
permitted_enctypes = rc4-hmac des3-cbc-sha1 des-cbc-crc des-cbc-md5
I deleted those from the .ini files on the client and on the server.
Now, when I try to get spark to use SSO, it states that it will attempt its login using xmpp/fqdn.of.openfireServer@DOMAIN.LOCAL to login.
The only thing that I can think of is that when I tested my keytab file from the client side that I did something inside of kerberos to screw it up. Otherwise, I am at a complete loss as to why Spark does not want to use my username. My knowledge of Kerberos is limited.
*UPDATE*
I was able to get spark to recognize the current user. I ended up running
kinit user@DOMAIN.LOCAL
to make spark change back to seeing my user.
Once I ran that, I am again able to SSO in the environment.