Issue description

When using systemd-networkd together with predictable interface names, there seems to be a race condition between networkd activating the interfaces and udevd renaming them, resulting in non-deterministic failure of interface renaming and setup.

For an example, see these hydra builds: failed and succeeded

Issue occurs on 18.03 and current master (i.e. with systemd 237 and 238).

It is probably an upstream bug (but systemd has not confirmed this yet). I found two similar reports: systemd/systemd#7293 and coreos/bugs#1767

Since the corresponding test is part of the tested jobs for the nixos-unstable-small and release-18.03-small channels, the sporadically failing test can delay the channels.

I suggest removing this test from the tested jobs for the time being until this is fixed.

Steps to reproduce

Although the issue seems non-deterministic in nature (see hydra builds), I can quite reliably reproduce it running the test on my local machine:
nix-build '<nixpkgs/nixos/tests/predictable-interface-names.nix>' -A vm-test-run-predictableInterfaceNames-with-networkd

Technical details

nixos 18.03.132008.ad771371fb2 or master e0c9a25