Parse and handle SSH public keys in different formats

[trstringer]

Proposed Commit Message

If SSH public keys from IMDS are in the OpenSSH format, then consume them directly. Otherwise, utilize the OVF path to retrieve the OpenSSH-formatted public keys.

Additional Context

This is the long-term fix for the regression that was fixed with the temporary/short-term PR #760

Test Steps

Checklist:

• My code follows the process laid out in the documentation
• I have updated or added any unit tests accordingly
• I have updated or added any documentation accordingly

[OddBloke]

Hey Thomas, a couple of high-level observations here; I haven't had a chance to dig in in more detail yet.

[github-actions]

Hello! Thank you for this proposed change to cloud-init. This pull request is now marked as stale as it has not seen any activity in 14 days. If no activity occurs within the next 7 days, this pull request will automatically close.

If you are waiting for code review and you are seeing this message, apologies! Please reply, tagging mitechie, and he will ensure that someone takes a look soon.

(If the pull request is closed, please do feel free to reopen it if you wish to continue working on it.)

[trstringer]

@OddBloke, let me know if there's anything else you want to see changed in this PR! // @mitechie

[trstringer]

Can I get this PR re-opened? @OddBloke @mitechie

[OddBloke]

Yep, and let me remove that tag too to stop it happening again.

[github-actions]

Hello! Thank you for this proposed change to cloud-init. This pull request is now marked as stale as it has not seen any activity in 14 days. If no activity occurs within the next 7 days, this pull request will automatically close.

If you are waiting for code review and you are seeing this message, apologies! Please reply, tagging mitechie, and he will ensure that someone takes a look soon.

(If the pull request is closed and you would like to continue working on it, please do tag mitechie to reopen it.)

[trstringer]

@OddBloke, I've implemented @smoser's suggestions and this PR is ready for review. Thanks!

[OddBloke]

Thanks, Thomas, this looks good to me! I have one proposed improvement inline, but that's a nit so I think this is fine to land without it.

What I would like to see is an integration test! I know that you have other work contingent on this landing, so we can do that as a follow-up PR to make life easier. This will likely require a little framework modification, but I believe we have the broad support for it in place. I've just filed https://bugs.launchpad.net/cloud-init/+bug/1922801, I'll expand over there.

[trstringer]

Closing this PR as its code was merged in #865.