If the key is in double quotes then it shouldn't use the nested structure. Can you confirm that the config you're generating has keys in quotes and is not simply `security.protocol: "SSL".

Also, typically = is used for assignments in HOCON, but : will work as well.

Another option is to generate your config as YAML and supply it to the Helm chart (if you're using Helm). It will automatically generate the K8s ConfigMap for you that's compatible with Lightbend Config.

I believe the application actually expects nested keys. In the readme, the example uses client.id = "admin-client-id", which would expand to "client": { "id": "admin-client-id" } in JSON.

So in my case, I just need to do something like:

"consumer-properties": {
  "security": {
    "protocol": "SSL"
  }
}

Closing this for now. Thanks for the response!

Ah, you may be right. We handle Kafka properties in a special way. https://github.com/lightbend/kafka-lag-exporter/blob/master/src/main/scala/com/lightbend/kafkalagexporter/AppConfig.scala#L75