That NetworkManager considers a link failed by default if all it gets is a link-local IPv6 address and nothing else, and proceeds to kill it off completely after DHCPv4 times out, is completely normal and sensible behavior. /s
@kloenk the problem isn't exactly NM, it's that stupid stack of cloud-init, netplan and NM. It just overwrites itself no matter on what side you make changes
@kloenk How I understand it, is the vendor-patched NM exports any changes to netplan, and then netplan generates the ephemeral NM connections. And any config options they don't explicitly handle get lost. Whatever the point of all that is supposed to be
@kloenk Setting IPv6 itself to link-local only should be fine though. That setting passes the magic purity test. I would have liked to preserve regular IPv6 connectivity, but ehh everything's still using IPv4 only on these trains anyway.
