[spec2x] coreos-teardown-initramfs-network: evaluate necessity of the script

[yuqi-zhang]

Currently on the spec2x branch of ignition, we have a simple script that tears down the network interfaces in the initramfs, right before we switch to the real root: https://github.com/coreos/ignition-dracut/blob/spec2x/dracut/30ignition/coreos-teardown-initramfs-network.sh

The original point of the script was that we wanted users to set up their networking (e.g. a static IP address) via ignition on RHCOS. NetworkManager inherited initamfs networking, so if the user did a dhcp to fetch ignition configs in the initramfs, the static networking would not be set up until a reboot. Note that we only brought down network interfaces and didn't really care about bonding, etc. since we didn't expect users to set that up in the initramfs.

Now the coreos-installer has the ability to persist kargs, so users are able to set up their networking that way. I think with that in place, and the fact that we're moving to NM managed initramfs networking, we should re-evaluate how we're using handling networking in the initramfs.

Also note that FCOS already uses NM dracut networking, and thus does not use ifcfg files as their source of truth, but instead NM keyfiles.

[jlebon]

Also note that FCOS already uses NM dracut networking

This is not yet the case. See coreos/fedora-coreos-config#259.

[yuqi-zhang]

Ah, my bad, thanks for the clarification. Is it correct to say "FCOS uses NetworkManager keyfiles, but do not yet use NM for dracut networking" then?

[dustymabe]

considering coreos/fedora-coreos-tracker#394 (comment) and that we just merged similar functionality into the master branch (#159) I think we have deemed functionality like this necessary.