configuration for host port assignment

[charlierudolph]

Ability to specify what port to start counting from, and ability to specify a host port for a given service. I think the service override should be in the application.yml in order to support reusable services.

services:
  service1:
    location:
    host_port: # specify dedicated host port for this service

initial_host_port: # specify what port to start counting from

@hugobho @alexdavid @Bowbaq @dminnear @bishtawi @allensallinger thoughts?

[hugoesthere]

This would only pertain to public services right? I'm not sure a public service would ever need to be reusable, one because I can't see any use case for that, but also because there's some configuration (mainly url), that I can't see being reused - so I don't think it'd be a bad idea to list these ports in service.yml. At the same time, it does make sense to list host ports in the app.yml as that gives you a high level view of which services are assigned which ports

[Bowbaq]

What's a reusable service? Is the intended behavior here the following:

• if you specify nothing, it starts numbering ports from a random value by increments of 1
• if you specify initial_host_port, it starts numbering ports from that value by increments of 1 (in which order? alphabetical on the service name?)
• if you specify host_port, the service uses that, regardless of the automatic numbering scheme