Document auto-restart of pods on secret rotation

[ewan-chalmers]

What type of PR is this?

/kind documentation

What this PR does / why we need it: Provides guidance for users of the auto-rotation feature of Secrets Store CSI Driver on how to implement optional auto-restart of workload pods when secrets are updated.

Which issue(s) this PR fixes (optional, using fixes #<issue number>(, fixes #<issue_number>, ...) format, will close the issue(s) when the PR gets merged):
Fixes #1647

Special notes for your reviewer:

TODOs:

• squashed commits
• includes documentation
• adds unit tests

[linux-foundation-easycla]

The committers listed above are authorized under a signed CLA.

• ✅ login: ewan-chalmers / name: Ewan Chalmers (06db65b, ea92357, d830b7f, 9d930b1, bd0c93f, c2ad53a, ed41ab2, 6b943eb, 4d17d7a, ea08454, 251459e, 35070d9, 62be1fb)

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[ewan-chalmers]

I have requested and am awaiting my addition to the kubernetes CCLA

[enj]

/assign aramase nilekhc

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[ewan-chalmers]

Looking at https://deploy-preview-1648--kubernetes-sigs-secrets-store-csi-driver.netlify.app/topics/auto-restart-on-rotation, I note that mermaid source is not rendered as a diagram in the mdbook output (as it is on github).

Simplest thing is to remove the diagram, but I could also look into whether mdbook configuration can be persuaded to render mermaid diagrams.

Looking at

• provide mermaidjs rendering rust-lang/mdBook#762
• https://github.com/badboy/mdbook-mermaid (via https://github.com/rust-lang/mdBook/wiki/Third-party-plugins)

I'll provisionally attempt to add mermaid support in this same PR with an update to docs/book/Makefile and docs/book/book.toml and see if the diagram renders in the preview.

[ewan-chalmers]

Well... that took a few more tries than I expected. The diagram now renders (FWIW - not a very exciting diagram) - https://deploy-preview-1648--kubernetes-sigs-secrets-store-csi-driver.netlify.app/topics/auto-restart-on-rotation#secretproviderclasspodstatus-custom-resource

While doing this, I notice that we should probably upgrade mbook and mbook-toc versions (as well as this new mbook-mermaid). I had to go quite a way back in mbook-mermaid tags to get one that works with our mbook version.

I'm happy to extract mermaid enabling into a separate PR or remove it altogether (along with the diagram src in this PR) if preferred.

[ewan-chalmers]

I'm unfamiliar with squashing commits and looks like there are loads of different ways to do so :/

[benjaminapetersen]

From an official SIG-Auth project, should we be linking out to this in the formal docs?

[benjaminapetersen]

This seems in tone a bit like a blog post for solving a particular problem, rather than a docs site entry. 🤔

[benjaminapetersen]

Per our discussion in the sync meeting, perhaps we keep, but just note that this is not (officially) supported or tested.

[ewan-chalmers]

You could see this doc as a continuation from https://github.com/kubernetes-sigs/secrets-store-csi-driver/blob/main/docs/book/src/topics/secret-auto-rotation.md.

I aimed for similar tone.

That doc links to Reloader.

I'm open to suggestions.

My motivation here is that the solution I arrived at and implemented was

• not obvious based on existing resources
• fairly straightforward given the necessary pointers