Migration Design: Rename Bundle to ClusterBundle

Signed-off-by: Erik Godding Boye <[email protected]>

design/20241124-rename-bunde-to-clusterbundle.md

@@ -0,0 +1,82 @@
+# Design: Renaming Bundle to ClusterBundle
+
+- [Release Signoff Checklist](#release-signoff-checklist)
+- [Summary](#summary)
+- [Motivation](#motivation)
+  - [Goals](#goals)
+  - [Non-Goals](#non-goals)
+- [Proposal](#proposal)
+  - [Risks and Mitigations](#risks-and-mitigations)
+- [Design Details](#design-details)
+  - [Test Plan](#test-plan)
+  - [Upgrade / Downgrade Strategy](#upgrade--downgrade-strategy)
+- [Alternatives](#alternatives)
+- [Future Work](#future-work)
+
+## Release Signoff Checklist
+
+This checklist contains actions which must be completed before a PR implementing this design can be
+merged.
+
+- [ ] This design doc has been discussed and approved
+- [ ] Test plan has been agreed upon and the tests implemented
+- [ ] User-facing documentation has been PR-ed against the release branch in [cert-manager/website]
+
+## Summary
+
+TODO
+
+## Motivation
+
+TODO
+
+### Goals
+
+- `Bundle` resource is renamed to `ClusterBundle`
+
+TODO: add more goals
+
+### Non-Goals
+
+- Change/fix/improve `Bundle`/`ClusterBundle` while renaming
+
+TODO: add more non-goals
+
+## Proposal
+
+TODO
+
+### Risks and Mitigations
+
+#### Target configmaps/secrets are accidentally deleted
+
+Since using owner references in this project, we need to be extra careful when performing changes like this.
+
+TODO: describe mitigation
+
+## Design Details
+
+### Test Plan
+
+TODO
+
+### Upgrade / Downgrade Strategy
+
+TODO
+
+## Alternatives
+
+### Just rename resource between releases
+
+Since the `Bundle` API version is `v1alpha1`, we could justify just doing the simplest thing and rename.
+This approach could cause potentially catastrophic failures in user clusters when the `Bundle` CRD is deleted
+since all target configmaps/secrets are owned by bundle and would be deleted by the Kubernetes garbage collector.
+
+### Doing Nothing
+
+See "Motivation" above.
+
+## Future Work
+
+- Introduce a **namespace-scoped** `Bundle` resource.
+- Integration with upstream [ClusterTrustBundle API](https://kubernetes.io/docs/reference/access-authn-authz/certificate-signing-requests/#cluster-trust-bundles).