kafka auth_error ai_generated true

org.apache.kafka.common.errors.PrincipalDeserializationException: Failed to deserialize principal from bytes

ID: kafka/principal-deserialization-failure

Also available as: JSON · Markdown · 中文
78%Fix Rate
85%Confidence
1Evidence
2023-09-15First Seen

Version Compatibility

VersionStatusIntroducedDeprecatedNotes
kafka_2.13-3.4.0 active — — —
kafka_2.13-3.5.1 active — — —
kafka_2.13-3.6.0 active — — —

Root Cause

Kafka broker cannot deserialize the principal object from the authentication token, often due to a custom principal builder class not being available or incompatible serialization format.

generic

中文

Kafka 代理无法从认证令牌反序列化主体对象，通常是由于自定义主体构建器类不可用或序列化格式不兼容。

Official Documentation

https://kafka.apache.org/documentation/#security_authz

Workarounds

  1. 85% success Add the custom principal builder JAR to the Kafka broker classpath (e.g., in `libs/` directory) and verify the `principal.builder.class` property in `server.properties` matches the fully qualified class name. 
    Add the custom principal builder JAR to the Kafka broker classpath (e.g., in `libs/` directory) and verify the `principal.builder.class` property in `server.properties` matches the fully qualified class name.
  2. 75% success If using SASL/PLAIN, switch to a simpler authentication mechanism that uses the default principal builder, e.g., set `sasl.enabled.mechanisms=PLAIN` and `principal.builder.class=org.apache.kafka.common.security.authenticate.DefaultPrincipalBuilder` in `server.properties`, then restart brokers. 
    If using SASL/PLAIN, switch to a simpler authentication mechanism that uses the default principal builder, e.g., set `sasl.enabled.mechanisms=PLAIN` and `principal.builder.class=org.apache.kafka.common.security.authenticate.DefaultPrincipalBuilder` in `server.properties`, then restart brokers.
  3. 90% success Ensure the custom principal builder class implements `org.apache.kafka.common.security.auth.PrincipalBuilder` and is serializable; recompile with the same Kafka version as the broker. 
    Ensure the custom principal builder class implements `org.apache.kafka.common.security.auth.PrincipalBuilder` and is serializable; recompile with the same Kafka version as the broker.

中文步骤

  1. Add the custom principal builder JAR to the Kafka broker classpath (e.g., in `libs/` directory) and verify the `principal.builder.class` property in `server.properties` matches the fully qualified class name.
  2. If using SASL/PLAIN, switch to a simpler authentication mechanism that uses the default principal builder, e.g., set `sasl.enabled.mechanisms=PLAIN` and `principal.builder.class=org.apache.kafka.common.security.authenticate.DefaultPrincipalBuilder` in `server.properties`, then restart brokers.
  3. Ensure the custom principal builder class implements `org.apache.kafka.common.security.auth.PrincipalBuilder` and is serializable; recompile with the same Kafka version as the broker.

Dead Ends

Common approaches that don't work:

  1. 95% fail

    The missing custom principal builder class is not loaded at startup; restarting does not add it to the classpath.

  2. 90% fail

    The issue is in the deserialization code, not in persisted data; clearing logs removes data but does not fix the class loading.

  3. 80% fail

    If the authentication token was serialized with a custom builder, the default builder cannot deserialize it, causing the same error.