Update KIND to v0.21.0 and document upgrade process

[killianmuldoon]

Since changes made to support KIND v0.20.0 - #8908 - the process for updating KIND as a dependency has gotten more complicated. This process should be correctly documented so the change can be done in future in a single PR.

This should include:

• bumping the version and sha of the default image e.g. 🌱 Add SHA to default KIND image used in e2e tests #8975
• adding the new image version and SHAs to the kind_mapper e.g 🐛 Add kind mapper #8880
• update kind versions in multiple places - 🌱 Update KIND to v0.20.0 #8908
• bump image versions used in Tiltfile, quickstart, clusterctl upgrade test and yamls e.g. 🌱 Update KIND to v0.20.0 #8908
• document the version change in the providers migration guide, tilt guide and the quickstart e.g. 🌱 Update KIND to v0.20.0 #8908

I may have forgotten / missed something in the above. My intention is to complete this work as part of the update to KIND v0.21.0 - the resulting documentation is likely to just be that PR and a link to the PR in some relevant place - possibly the release guide.

Note: KIND v0.21.0 has now been released https://github.com/kubernetes-sigs/kind/releases/tag/v0.21.0

/kind documentation

[killianmuldoon]

/assign

[killianmuldoon]

/triage accepted

[killianmuldoon]

/unassign

/help

This should be done during the next KIND release to ensure we have a single PR linked somewhere showing how to bump the KIND version.

[k8s-ci-robot]

@killianmuldoon:
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In response to this:

/unassign

/help

This should be done during the next KIND release to ensure we have a single PR linked somewhere showing how to bump the KIND version.

Instructions for interacting with me using PR comments are available here. If you have questions or suggestions related to my behavior, please file an issue against the kubernetes/test-infra repository.

[killianmuldoon]

@kubernetes-sigs/cluster-api-release-team maybe a task someone might be interested in picking up?

[cahillsf]

/assign

[chrischdi]

/reopen

Do we have to improve docs (as the title / description says)?

[k8s-ci-robot]

@chrischdi: Reopened this issue.

In response to this:

/reopen

Do we have to improve docs (as the title / description says)?

Instructions for interacting with me using PR comments are available here. If you have questions or suggestions related to my behavior, please file an issue against the kubernetes/test-infra repository.

[cahillsf]

Do we have to improve docs (as the title / description says)?

ah right -- i can open a followup PR, will update the k8s upgrade issue template with a link to this most recent kind bump pr. anything else that should be added? maybe some note about incrementing the Mode in the mapper file when there is a code change required in the Docker provider?

[chrischdi]

👍 That sounds awesome. Thanks!