'default' host_network isn't found when same interface is specified under named host_network

[kevinschoonover]

Nomad version

Output from nomad version

> nomad version
Nomad v1.6.1

Operating system and Environment details

Debian 11 x86

Issue

consider the following config.hcl

# config.hcl
client {
  network_interface = "tailscale0"

  host_network "tailscale" {
    interface = "tailscale0"
  }

  host_network "public" {
    interface = "wlan0"
  }
}

whenever you would schedule the following job

# job.hcl
job "docs" {
  datacenters = ["dc1"]

  group "example" {
    network {
      port "http" {}
    }
    task "server" {
      driver = "docker"

      config {
        image = "hashicorp/http-echo"
        ports = ["http"]
        args = [
          "-listen",
          ":5678",
          "-text",
          "hello world",
        ]
      }
    }
  }
}

you would see * Constraint "missing host network \"default\" for port \"http\"": 1 nodes excluded by filter because the 'default' host_network alias is being replaces with 'tailscale'.

I submitted #18096 which will properly append the default alias. Please let me know if there are any questions or things I can add!

[tgross]

Good debugging! I was able to reproduce this on a multi-homed machine and it doesn't repro if any of the elements are missing here, so I think you're on the right track. Review incoming for your PR shortly.