Lost interface on upgrading 1.4-rolling

I’m running a virtual VyOS in Proxmox, with two interfaces:

  • eth0 paravirtualized VirtIO bridge, 10 GbE (LAN)
  • eth1 pass-through 1 GbE Ethernet (WAN)

When rebooting after downloading a new system image, going from 1.4-rolling-202203300217 to 1.4-rolling-202204190217, my eth0 was suddenly called e3 instead. And of course the config failed because eth0 was missing.

Rolling back to 1.4-rolling-202203300217 didn’t resolve the problem.

After adding hw-id to the eth0 interface in /config/config.boot and rebooting it came up as expected. And I was able to update and boot the 1.4-rolling-202204190217 system image successfully.

My question is: why did eth0 suddenly become e3, and is it good practice to always define each interface by it’s hw-id?

Update: The MAC address on eth0 in Proxmox is static and hasn’t changed.