Kafka features should give better errors on authentication failure

[faec]

Our Kafka features (the Filebeat input and Libbeat output) are based on Sarama, which handles authentication to the Kafka cluster. With some authentication types, notably Kerberos, Kafka doesn't always pass through the cause of an authentication failure, and reports it as a generic disconnection. This makes it hard to troubleshoot configuration errors and potential bugs arising from Kafka / Kerberos authentication.

We already have a fork of Sarama including fixes for other issues we've encountered, we should update it to preserve authentication errors and pass them through to the error channel (and hopefully contribute it back upstream if we can find an approach everyone is happy with).

[elasticmachine]

Pinging @elastic/agent (Team:Agent)

[elasticmachine]

Pinging @elastic/elastic-agent-data-plane (Team:Elastic-Agent-Data-Plane)

[jlind23]

@faec Any update here?