On Tue, Aug 4, 2020 at 4:22 PM Bao Nguyen <baondt@xxxxxxxxx> wrote:
Hello,
Recently I found that my kvm guest has inconsistent network names every reboot. Here is the log
myPC kernel: virtio_net virtio0 eth000102030405: renamed from eth0
myPC kernel: virtio_net virtio1 eth000102030406: renamed from eth1
myPC kernel: virtio_net virtio2 eth000102030407: renamed from eth2
Those look different from udev's typical "persistent" naming scheme, which never uses the eth* prefix. It might be a custom udev rule, or another (non udev) service doing the renaming – the same message is shown in all cases.
myPC kernel: virtio_net virtio0 eth1: renamed from eth000102030405
myPC kernel: virtio_net virtio1 eth3: renamed from eth000102030406
myPC kernel: virtio_net virtio2 eth4: renamed from eth000102030407
This *might* be an old "70-persistent-net" udev rules file (the kind that Debian used to auto-generate in the past).
Looks like systemd-udevd has renamed the interface name but incorrectly. Could you please let me know if the above log is printed out because system-udevd runs or from kernel?
The message is shown by the kernel, but the actual renaming could have been done by anything – udev, `ip link`, or literally any other userspace tool.
And why the name is changed incorrectly, is it due to some udev rules?
Could be either custom udev rules, or custom /etc/systemd/network/*.link files, or some network management daemon with its own renaming logic. My guess is that lines 1-3 are a custom rule and 4-6 are 70-persistent-net.
You might find at least some information by running `udevadm test /sys/class/net/eth0` (replace eth0 with any interface that currently exists).
Systemd's standard interface renaming rules (at 80-net-setup-link.rules) were written to never override any custom name that earlier rules might have set.
Is there any way I can change to make the interface name persistent on each reboot.
The kernel does not remember anything across reboots. The only way to make a custom name persistent is to rename it from userspace every single time (e.g. udev rules).
Mantas Mikulėnas
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