Switching from Ubuntu version to another leaves the selected kernel version stuck, resulting in incorrect path

[Christian Grabowski]

Related thread here: https://discourse.maas.io/t/select-image-used-for-commission-per-commission/4784

When commissioning a machine with one given version, for instance, Bionic, and then switching to another version, say Focal, and a minimum kernel version was selected, the UI will display no minimum kernel is selected, while the prior kernel version is in fact selected, leading to invalid paths for the given kernel.

[Evan Sikorski (evan.sikorski)]

This is impactful to my company's environment for the following reasons

1. Many machine were built a year ago or more using 18.x as the commission/ephemeral image. (4000 machines at least)
2. New machines have required 20.x in order to detect the hardware
3. We don't deploy Ubuntu, so the options to pick during deploy/erase/etc are NOT available

The only way to remediate this is to either:

1. Manually edit each node's hwe entry to match the current comission version
2. Create symlinks in the image directories that redirect systems looking for wrong A in right B, which feels like it could end up causing issues later down the line.

[Jerzy Husakowski (jhusakowski)]

It seems that MAAS is not treating the minimum kernel version as a true "minimum", but as a required version, leading to invalid paths.