Kerberos auth used by filebeat input, ignored by metricbeat input

[fearful-symmetry]

Right now, the kafka filebeat input allows the user to specify a Kerberos config:

beats/filebeat/input/kafka/config.go

Lines 52 to 53 in 18a7e54

	Kerberos *kerberos.Config `config:"kerberos"`
	Username string `config:"username"`

but there's no kerberos config in the metricbeat kafka config:

beats/metricbeat/module/kafka/config.go

Lines 28 to 36 in 18a7e54

	type metricsetConfig struct {
	Retries int `config:"retries" validate:"min=0"`
	Backoff time.Duration `config:"backoff" validate:"min=0"`
	TLS *tlscommon.Config `config:"ssl"`
	Username string `config:"username"`
	Password string `config:"password"`
	ClientID string `config:"client_id"`
	Sasl kafka.SaslConfig `config:"sasl"`
	}

This is (obviously) a bit confusing for users, as the support for kerberos is a bit inconsistent.

[elasticmachine]

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

[nimarezainia]

This user is actually using Elastic Agent with the Kafka integration (custom logs variant as well). So ideally those integrations are modified to allow kerberos auth.

This is issue needs to be resolved before that happens however.