FFE: maas support for hardware enabement kernels (HWE)

[Scott Moser]

[Description]
MAAS does not currently support installation of Hardware Enablement kernels [1]. This is essential function to support Ubuntu LTS releases of 12.04 and 14.04.
  --
  [1] https://wiki.ubuntu.com/Kernel/LTSEnablementStack

[Proposed Changes]
The full design and implementation are not yet finalized. The end result will allow users of maas to utilize the hardware enablement kernels for each of
In order to support the HardwareEnablementStack effort, MAAS needs to allow the user to be able to Enlist, Commission, and Deploy systems with an HWE kernels. For development and support purposes it also needs to allow site-customized kernels to be used. This is essential when bringing up new hardwa
re that isn't fully supported in Ubuntu.

The general plan is to enhance the simple streams data that is available on maas.ubuntu.com/images to list HWE kernels and also make it better able to describe what "subarch" are supported by a given kernel.

We also plan to make "fat initramfs" available to support booting a single ephemeral image with multiple different kernels. This is necessary because keeping a 1:1 relationship of kernel to ephemeral image is not supporatable given the download size. This is the reason for the cloud-initramfs-tools task.

The MAAS team will work in conjuction with Ubuntu teams and other Canonical teams to bring these features in.

See bug 1281881 for MAAS FFe

[Dave Walker (davewalker)]

Please can you provide more information on the status of the 'fat initrd', is this feature developing well? Has this concept been proved against the 12.04 HWE options as reference, in particular arm based servers. Can you confirm that arm based deploying is no-worse than current.

Thanks