Disable hardcoded MaaS curtin scripts

[kreeuwijk]

Change description

The MaaS support added to image-builder contained hardcoded hooks and scripts for curtin. However, MaaS has since evolved and now includes all those steps (and more) already builtin. The builtin steps are more powerful & flexible, and should be used instead. For example, the builtin properly reconfigures the UEFI boot order (to keep PXE at the top) and handles situations where the MaaS proxy should be used for APT package updates.

Hence, this PR comments out the copying of the hardcoded curtin files for MaaS, so that the standard curtin hooks from MaaS can be used instead.

• Is this change including a new Provider or a new OS? (y/n) n

Related issues

• Fixes issues with the UEFI boot order not getting repaired, and MaaS proxy scenarios not working for custom MaaS images generated by this builder.

Additional context

[k8s-ci-robot]

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[k8s-ci-robot]

Hi @kreeuwijk. Thanks for your PR.

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[mboersma]

/ok-to-test

[mboersma]

/retest

[AverageMarcus]

/assign @vasartori

[drew-viles]

/lgtm

@vasartori are you able to take a look at this?

[moondev]

@kreeuwijk Do you know the specific MaaS version that started including these curtin hooks by default?

However, MaaS has since evolved and now includes all those steps (and more) already builtin.

For all MaaS versions previous to this new change, it would seem leaving the hooks out would build a non bootable image. Perhaps a maas_version variable could conditionally add the hooks, or at the least call it out in the README.

The image-builder release that first included support for MaaS was July 4 https://github.com/kubernetes-sigs/image-builder/releases/tag/v0.1.45

Have the new hooks only landed in MaaS 3.7.0~beta1?

[kreeuwijk]

@moondev MaaS doesn't ship its own curtin hooks, it just installs the python3-curtin package. They are then present on the server as:

/snap/maas/current/usr/lib/python3/dist-packages/curtin/commands/curthooks.py

So that means there's no dependency on the MaaS version; any version will install the latest python3-curtin package, which has all the hooks you could wish for.

[moondev]

@moondev MaaS doesn't ship its own curtin hooks, it just installs the python3-curtin package. They are then present on the server as:

/snap/maas/current/usr/lib/python3/dist-packages/curtin/commands/curthooks.py

So that means there's no dependency on the MaaS version; any version will install the latest python3-curtin package, which has all the hooks you could wish for.

Thanks for the clarification and great to hear images won't be fragmented by their destination MaaS version. Cheers.

[drew-viles]

So I'm happy with this in theory but I'm not a user of MAAS so cannot confirm anythign from my side. I was hoping @vasartori would be able to check this out as they are the original contributor of the MAAS code.

If they don't come back soon and we're all happy I'm happy to approve this.