On Mon, Aug 30, 2021 at 10:20:46PM +0200, Steve Keller wrote: > I plan to upgrade a server from Debian stretch to buster. Having read > the release notes I wonder what's the best way to avoid the new scheme > of unpredictable network interface names.
You say "server", so I'm guessing it has more than one NIC. That means the old way (net.ifnames=0) is not viable. Your best strategy is to create systemd.link(5) files, and give the NICs the names you want them to have, based on their MAC addresses. For example: unicorn:~$ cat /etc/systemd/network/10-lan0.link [Match] MACAddress=18:60:24:77:5c:ec [Link] Name=lan0 unicorn:~$ ip link 1: lo: <LOOPBACK,UP,LOWER_UP> mtu 65536 qdisc noqueue state UNKNOWN mode DEFAULT group default qlen 1000 link/loopback 00:00:00:00:00:00 brd 00:00:00:00:00:00 2: lan0: <BROADCAST,MULTICAST,UP,LOWER_UP> mtu 1500 qdisc pfifo_fast state UP mode DEFAULT group default qlen 1000 link/ether 18:60:24:77:5c:ec brd ff:ff:ff:ff:ff:ff This is also viable on a single-NIC machine (like mine), but in that case net.ifnames=0 would also suffice.