Restrict security group to tls port 9094

[dawidmalina]

Would be good if security group created open ports related to kafka 9094 (tls)

[korenyoni]

Thanks for pointing this out.

Mind you that this is not only port 9094, but also other protocols, depending on the values of var.client_broker, var.client_sasl_scram_enabled, var.client_sasl_iam_enabled.

For reference:

• https://registry.terraform.io/providers/hashicorp/aws/latest/docs/resources/msk_cluster#attributes-reference
• https://docs.aws.amazon.com/msk/latest/developerguide/client-access.html#port-info

We are working on this in #44