fix(ubuntu): Configure arm64 to use archive.ubuntu.com

[waveform80]

Note: I have not added unit tests, as the test suite still passes (on my local machine). Also, no documentation changes appear to be necessary (this is purely an infrastructure configuration change).

• I have signed the CLA: https://ubuntu.com/legal/contributors
• I have included a comprehensive commit message using the guide below
• I have added unit tests to cover the new behavior under tests/unittests/
  • Test files should map to source files i.e. a source file cloudinit/example.py should be tested by tests/unittests/test_example.py
  • Run unit tests with tox -e py3
• I have kept the change small, avoiding unnecessary whitespace or non-functional changes.
• I have added a reference to issues that this PR relates to in the PR message (Refs integration: do not LXD bind mount /etc/cloud/cloud.cfg.d #1234, Fixes integration: do not LXD bind mount /etc/cloud/cloud.cfg.d #1234)
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  • Cloud-config documentation is generated from the jsonschema.
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Proposed Commit Message

fix(ubuntu): Configure arm64 to use archive.ubuntu.com

Fixes GH-6825
LP: #2147101

Merge type

• Squash merge using "Proposed Commit Message"
• Rebase and merge unique commits. Requires commit messages per-commit each referencing the pull request number (#<PR_NUM>)

[blackboxsw]

Thanks @waveform80 for the submittal and @utkarsh2102 context.

The changeset looks good. Note that this fix will only configure new instance launches with the appropriate archive.ubuntu.com mirror.

In the absence of an additional debian postinst change, cloud-init will NOT update the config in /etc/apt/sources.list.d/ubuntu.sources across package upgrade or system reboot because cloud-init only writes this out on first boot.

QUESTION:
Do we want this change to take place across cloud-init package upgrade as well?
If so we'll need to also provide a patch to ubuntu/devel: cloud-init-base.postinst to sed the mirror URI value in /etc/apt/sources.list.d/ubuntu.sources.

[waveform80]

Probably not -- for new installs, the image build (either livecd-rootfs or ubuntu-image) handles configuring ubuntu.sources. For release upgraders, u-r-u should gain a quirk to handle migrating setups, but I don't think we want to do anything to regular upgrades.

However, @utkarsh2102 feel free to contradict me!

[blackboxsw]

I'll merge this and we can resolve any discussion about need to migrate across pkg upgrade path afterwards.

1. Also @utkarsh2102 @waveform80 shall we presume we'd like this in resolute? If so we can generate and upload a snapshot once integration tests are clear on our daily PPA ppa:cloud-init-dev/daily to allow dailies to get some exposure before final release.