The default Tank.Host: uplink + DNS read straight from application config.
Runs anywhere, with no host-network integration.
config :tank, Tank.Host.Static,
uplink: "eth0",
dns: ["10.0.0.1"]uplink/0 returns {:error, :no_uplink_configured} until :uplink is set, so
a pod that uses parent: :auto fails clearly rather than silently. dns/0
defaults to an empty list.