What is a generic unique id that I can use for messages I receive from a consumer?

A producer application in a developer machine was able to send messages to a Kafka topic. After copying the producer application into another developer's machine, the producer is able to connect to Kafka but unable to produce to the same Kafka topic because of an authorization issue. What is the likely issue?

In Avro, adding a field to a record without default is a __ schema evolution

What is true about replicas ?

What's a Kafka partition made of?