how to specify env vars in connector config

[cheskayang]

Use case:

i have kafka connect running with a small number of pods
this is a batch like connector, and i want to avoid frequent rebalancing.
By setting group.instance.id, this can be achieved. however since there will be multiple pods, e.g. connect-0, connect-1, I need to have the instance id to be sth like this ${env:HOSTNAME}
i followed configurations here https://github.com/strimzi/kafka-env-var-config-provider
but it didn't work with connector, i'm getting error

Group instance id is invalid: '${env:HOSTNAME}' contains one or more characters
          other than ASCII alphanumerics, '.', '_' and '-'\n"

Please suggest the expected way to achieve this. ty!

[scholzj]

You should share the full configs and logs to give us better idea what the problem might be. Also, keep in minf that the Strimzi EnvVar provider is for a long time deprecated (and removed IIRC). You should use the Kafka one.