Comment 1 for bug 1524452

In curtin/examples/test/basic_network.yaml
You can see we define an eth2 that is present, but is not configured.

This results in the following eni:

auto eth0
iface eth0 inet dhcp

auto eth1
iface eth1 inet static
    gateway 10.0.2.1
    address 10.0.2.100/24
    mtu 1492

auto eth1:1
iface eth1:1 inet static
    dns-nameservers 8.8.8.8
    dns-search barley.maas
    address 10.0.2.200/24
    mtu 1492

auto eth2
iface eth2 inet manual

The auto then triggers the ifwait service to wait on it; but it never will.

What is the expected behavior for curtin when we see an 'type: physical' in the config?

        - type: physical
          name: eth2
          mac_address: "52:54:00:12:34:04"

It feels like we should emit the udev rules to ensure we do the iface to mac_address mapping, but in the absence of
a subnet to skip including it eni.

Will need to see if this affects things like bonds/bridges which expect an iface entry for the device.

For the test case Speed, we can certainly apply a subnet configuration here which will ensure the iface comes up and we save the 120 seconds of execution time, but will need to see whether we should skip emitting the auto XXX if no subnet is attached.