On the new and upcoming Ubuntu Core 18 systems we will use the 4.15 version of the linux kernel. This raise the question how we specific this in the model assertion. Right now (in Ubuntu Core 16) we have e.g.:
kernel: pi2-kernel
in the model assertion for the pi2.
The core-pi2-18.model assertion will need to contain something to specify that we want a different version. I can see some options:
kernel: pi2-kernel
kernel-track: 4.15
kernel: pi2-kernel/4.15 # specify track inline
kernel: pi2-kernel-4.15 # totally different snap name for ver 4.15
Option 1 looks the cleanest. Option 2 feels like an unusual spelling of a channel, where the track usually precedes the risk but in this case is succeeding a snap name.
Seems reasonable to have that. We just need to watch out for the points above: once we allow tracks to be specified, they need to be respected. Otherwise we’ll open a gap and will be locked out into a backward compatibility issue.
After some further deliberations we decided to use the following form to specify the kernel-track. So instead of the explicit kernel-track: track we now do: