Remapping Ethernet Interfaces using hw-id / mac address

[fsbof]

Using version VyOS 1.5-rolling-202407280023 and I have encountered what I think is a strange behaviour.

I am booting an instance of VyOS on KVM that has 9 interfaces.

On booting the assigned names (eth0, eth1 etc) are out of order with the mac-addresses.

I expect eth8 to be eth0, eth0 to be eth1, eth1 to be eth2 etc

vyos@vyos:~$ show interfaces 
Codes: S - State, L - Link, u - Up, D - Down, A - Admin Down
Interface    IP Address    MAC                VRF        MTU  S/L    Description
-----------  ------------  -----------------  -------  -----  -----  -------------
eth0         -             52:54:00:ab:cd:01  default   1500  u/u
eth1         -             52:54:00:ab:cd:02  default   1500  u/u
eth2         -             52:54:00:ab:cd:03  default   1500  u/u
eth3         -             52:54:00:ab:cd:04  default   1500  u/u
eth4         -             52:54:00:ab:cd:05  default   1500  u/u
eth5         -             52:54:00:ab:cd:06  default   1500  u/u
eth6         -             52:54:00:ab:cd:07  default   1500  u/u
eth7         -             52:54:00:ab:cd:08  default   1500  u/u
eth8         -             d4:93:90:2b:a0:9e  default   1500  u/D
lo           127.0.0.1/8   00:00:00:00:00:00  default  65536  u/u
             ::1/128

Using delete interfaces ethernet ethX and set interfaces ethernet ethX hw-id '<mac>' allows me to change the assigned interfaces and it seems to work correctly and allow me to apply the config I have prepared.

vyos@vyos:~$ show interfaces 
Codes: S - State, L - Link, u - Up, D - Down, A - Admin Down
Interface    IP Address    MAC                VRF        MTU  S/L    Description
-----------  ------------  -----------------  -------  -----  -----  -------------
eth0         -             d4:93:90:2b:a0:9e  default   1500  u/D
eth1         -             52:54:00:ab:cd:01  default   1500  u/u
eth2         -             52:54:00:ab:cd:02  default   1500  u/u
eth3         -             52:54:00:ab:cd:03  default   1500  u/u
eth4         -             52:54:00:ab:cd:04  default   1500  u/u
eth5         -             52:54:00:ab:cd:05  default   1500  u/u
eth6         -             52:54:00:ab:cd:06  default   1500  u/u
eth7         -             52:54:00:ab:cd:07  default   1500  u/u
eth8         -             52:54:00:ab:cd:08  default   1500  u/u
lo           127.0.0.1/8   00:00:00:00:00:00  default  65536  u/u
             ::1/128

However once I save the configuration and reboot the router, I get the following error;

<snip>
[   24.936976] vyos-router[985]: Waiting for NICs to settle down: settled in 7sec..
[   26.811361] vyos-router[985]: Mounting VyOS Config...done.
[   40.599154] vyos-router[985]: Starting VyOS router: migrate system configure failed!
[   41.502306] vyos-config[1007]: Configuration error

Welcome to VyOS - router ttyS0

… and the interfaces have changed.

vyos@ert:~$ show interfaces 
Codes: S - State, L - Link, u - Up, D - Down, A - Admin Down
Interface    IP Address    MAC                VRF         MTU  S/L    Description
-----------  ------------  -----------------  --------  -----  -----  ---------------------------
br100        -             de:f6:be:42:cd:36  VRF100   1500  u/D    BR100
br101        -             a6:8f:f0:9b:01:07  VRF101   1500  u/D    BR101
eth0         -             d4:93:90:2b:a0:9e  default    1500  u/D    ETH0
eth9         -             52:54:00:ab:cd:08  default    1500  u/u
eth10        -             52:54:00:ab:cd:04  default    1500  u/u
eth11        -             52:54:00:ab:cd:03  default    1500  u/u
eth12        -             52:54:00:ab:cd:01  default    1500  u/u
eth13        -             52:54:00:ab:cd:06  default    1500  u/u
eth14        -             52:54:00:ab:cd:07  default    1500  u/u
eth15        -             52:54:00:ab:cd:02  default    1500  u/u
eth16        -             52:54:00:ab:cd:05  default    1500  u/u
lo           127.0.0.1/8   00:00:00:00:00:00  default   65536  u/u
             ::1/128

Perhaps I am not using set interfaces ethernet ethX hw-id '<mac>' correctly. Wondering if anyone can suggest what might be happening here or what I might be doing incorrectly?

[Apachez]

Probably easier if you at first step (when your interfaces are “out of order”) save the config and then manipulate that config file with vi or such (located in /config/config.boot) and then reboot the box.

[fsbof]

That was a useful tip and it pointed me to the problem, which was definitely user error (me!). I am not entirely sure how I did it but the mac address tied to eth1-eth8 were different to those above and which didn’t exist on the system. I’m guessing I did it before somehow and was never really clearing the interfaces properly from the config. So - Solved, and I learnt another useful troubleshooting tool. Thanks.