Kerberos authentication stopped working.

Issue:

The logs are filled with several exceptions related to Kerberos authentication and Kinit. 

E.g.:

WARN ConnectToCluster - Error receiving response from <server-host>
org.apache.kudu.client.NonRecoverableException: Server requires Kerberos, but this client is not authenticated (kinit) 
...
Caused by: javax.security.sasl.SaslException: GSS initiate failed [Caused by GSSException: No valid credentials provided (Mechanism level: Failed to find any Kerberos tgt)]
[thread:kafka-kerberos-refresh-thread<->] WARN KerberosLogin - [Principal=sdc_prd@TOLLGROUP.LOCAL]: Not attempting to re-login since the last re-login was attempted less than 60 seconds before

.

[thread:Kerberos-Renewal-Thread<>] ERROR SecurityContext - Stopping renewal thread because of exception: java.lang.RuntimeException: Could not get Kerberos credentials

Solution:

The last exception from the examples is telling us that the Kerberos renewal thread was stopped because of the exceptions. Since the renewal thread died, as a result, no re-logins have been happening since and the Kerberos ticket for your SDC may have expired already.  You will need to restart SDC to get the renewal thread back up again.