RFC: handling kernel cmdline options in gadget snaps

[Alexander Sack]

On Tue, Jul 7, 2015 at 8:05 PM, Sergio Schvezov
<sergio.schvezov at canonical.com> wrote:
> On Tue, Jul 07, 2015 at 11:37:12AM -0600, Ben Howard wrote:
>>
>> What about making /etc/default/grub.d a writable path? Then a user would
>> simply need to provide a config with
>> GRUB_CMDLINE_LINUX_DEFAULT="console=tty1".
>>
>> But I think that this highlights the need for providing a simple way for
>> users to populate the writable paths at build time. As I have been
>> building Cloud Images, its a PITA to populate the writable paths. I
>> think that having a "--writable <tarball>" option that takes <tarball>
>> and populates /writable with the contents could solve a lot of pain.
>> Having this feature would mean that instead of having to support the
>> never-ending whack-a-mole requirements of "--<whatever>", users could
>> use "--writable <tarball>".
>
> I;m lobbying for doing most of this through snappy config. A big blob of
> config to setup and I don't mind having a syntax that looks like:
>
>     ubuntu-device-flash core 15.04 --config config.yaml ...
>
> For what it's worth, those grub dirs have become irrelevant and snappy
> has complete control of the bootloader in the development series. You
> can easily write your own grub.cfg from the gadget today.

I agree that snappy config feels the way to go. That's how you do it
after first boot and how you do things when producing factory images
(through config in gadget). Having and overwrite option in udf for
when developing your custom gadget sounds super sensible too and doing
this will avoid adding more and more special config flags in udf.

Thanks!