ECS (container module): Test with classic ELB

[itsdalmo]

The ECS module was cobbled together and still needs to be tested with an ELB. Should also consider whether a classic ELB makes sense with ECS since you can only register a single load balancer with a service, and you have to specify a port in the process.

For e.g. Concourse, it might be ok to use ECS with a classic ELB and associate the web-port with the load balancer, while still passing the TSA port from the ELB to the instance?

[itsdalmo]

Wait for Network Load Balancers to be added to terraform and update/test then.

[itsdalmo]

This will be tested when the concourse/drone.io modules are updated to use NLB's.