🛡️ Solving the Kerberos User Authentication Issue in Spark Docker Streaming
Solving the Kerberos User Authentication Issue in Spark Docker Streaming While building my real-time streaming pipeline using Spark, Kafka, and Docker, I ran into a Spark error related to Kerberos authentication - when I wasn’t even using Kerberosa. org.apache.hadoop.security.KerberosAuthException: failure to login: javax.security.auth.login.LoginException: java.lang.NullPointerException: invalid null input: name ❓ What triggered the problem? I was using the official apache/spark:3.5.0 Docker image. Spark inside Docker was trying to resolve Hadoop’s default authentication mechanism. Hadoop tries to retrieve the current OS user via: UnixPrincipal(name) Inside Docker containers, my app was running as UID/GID that had no proper username mapping. This caused: invalid null input: name because UnixPrincipal() received null. ...