Code review comment for lp://staging/~ltrager/curtin/lp1640519

Thanks Lee - I agree that querying flash-kernel would be a more robust solution. I'm not sure which sets of problems you are trying to solve, and which ones are ancillary, so here's some more background/questions.

flash-kernel installs a kernel hook that runs /usr/sbin/flash-kernel on every kernel upgrade. This has caused a problem in the past, because flash-kernel will return an error on systems it does not support, causing the apt upgrade process to error. We've therefore historically had code that tries to recognize the system, and only install flash-kernel if it should run. In short - flash-kernel was the problem there, not u-boot-tools. u-boot-tools can be installed on any system innocuously. If that's the problem you are trying to address (which I don't believe is a problem anymore), then I'd suggest removing flash-kernel after this test.

Today, installing flash-kernel and/or u-boot-tools on any MAAS-supported system should be fine. The only reason I see to selectively install u-boot-tools is to save install space. If space is a concern, then this helps to address that. You could also remove flash-kernel if unneeded to save more space.

If space isn't an issue, and we believe that installing flash-kernel everywhere is safe these days, then the simplest fix might be to just install flash-kernel/u-boot-tools on all arm systems.

If you do stick with the system-matching approach, you might want to consider a more generic "optional package" install method than "if flash-kernel-supported then install u-boot-tools". flash-kernel can tell you what additional packages it requires on the target platform:

machine="$(get_cpuinfo_hardware)"
get_machine_field "$machine" "Required-Packages"

This way you would only install u-boot-tools on platforms that really need it, and also support other required packages than u-boot-tools.