Going between a 1.1.x image and the latest 1.2.x jessie preview builds results in an interface that was eth1 in 1.1.x become eth0 in 1.2.x, etc.
Changing persistent net rules in 1.2 image allows you to change back to previous index and fixes this issue, but I think people would rather not have to do that with an upgrade :)
persistent net rules is not used in vyos? where do you get that from?
it uses hw-id from config file.
Yes, I get that it's supposed to use hw-id, but using the same configuration and upgrading on my build has caused the issue unless persistent net rules is modified.
I can also replicate this on a VM with 2 NICs, where the interface index may have been edited prior. Basically I think depending on which device loads first then the underlying system causes the system to assign that interface index to it.
For example also, if we rename an interface tied to a hw-id and assign it interface index of a higher number (e.g. eth5) on a 1.1.x build, it ends up as eth0 again when updating to one of the preview builds.
@Boltsie It should be fixed in this iso: http://dev.packages.vyos.net/iso/current/amd64/vyos-999.201704290958-amd64.iso and next to follow.
Could you please test if this fixes it for you?