focker/focker-compose.yml

variables:
  ext_if: em0
  gateway_ip: 127.0.0.2

defaults:
  jail:
    mount.devfs: true
    interface: lo1
    exec.start: /bin/sh /etc/rc
    exec.stop: /bin/sh /etc/rc.shutdown
  pf: |
    rdr on $(ext_if) proto tcp from any to any port 80 -> $(jail_ip)

services:
  gateway:
    image: freebsd-12.1
    jail:
      ip4.address: $(gateway_ip)
    pf:
      - pass on $(ext_if)

volumes:
  gateway-data: {}