Dynamic Port Mapping through Support App LB / Application Entities

[tribaljack]

trafficstars

Opening up path to deliver dynamic port mapping, currently possibly through ALB or Consul.

Current ALB only supports HTTP, with TCP support coming.

[zpatrick]

I propose we introduce a new entity, application, that encapsulates both a service and an application loadbalancer. The terraform design would look something like:

resource "layer0_application" "guestbook" {
    name        = "guestbook"
    environment = "${layer0_environment.demo.id}"
    deploy      = "${layer0_deploy.guestbook.id}"
    scale       = 3
    private     = false

    route {
        host_port      = 443
        container_name = "guestbook"
        container_port = 80
        protocol       = "https"
        certificate_id = "{var.certificate_id}"
        health_check   = "/health"
    }
}

The example above would create the following resources:

• An ALB inside the Layer0 environment with a listener for the route specified; 443/HTTPS in this example. The private field specifies if the ALB is internet-facing or not (same as how we use ELBs today).
• A Target Group for the route specified; guestbook:80 in this example. Note that we would terminate all SSL connection on the target group level (the same thing we do with ELBs today), so the 443:80/HTTPS route is 80/HTTP on the target group. Each target group would also use the specified health_check; /health in this example.
• A layer0 service named guestbook. This service would configured to use the ALB we created above.

The CLI could look something like:

$ l0 application get *
SERVICE ID    SERVICE NAME  ENVIRONMENT  ROUTE                   DEPLOYMENTS  SCALE
guestbook123  guestbook     dev          443:guestbook:80/HTTPS  guestbook:1  1/1

$ l0 application create --route 443:guestbook:80/HTTPS --health-check "/" demo guestbook guestbook:latest

[andycmaj]

dunno if this this the right issue to comment on for ALB support, but this would be a really nice to have for WebSockets.

just learned that ELBs don't really support WebSockets for a number of reasons (affinity, protocols, headers, etc.)

• https://mixmax.com/blog/deploying-meteor-to-elastic-beanstalk-1

ALB has much better support here, so would unlock some scenarios for us.