This is to track the changes we still want to make to the [`ServerSideApply`](https://github.com/kubernetes/enhancements/issues/555) alpha feature, now that it's feature branch has merged into master. These were previously tracked in a Working Group Apply sprint planning spreadsheet, but are being moved here for more transparency.

Dry-run and `kubectl diff` features are tracked separately:
- Dry-run: #68514
- `kubectl diff`: #68526

## Beta 2
Topics are mostly sorted by priorities.

### Scalability
- [ ] Reduce further the number of allocations performed when tracking field ownership: @apelisse
  - [x] Improve benchmarks to be closer to real-life and cover more scenarios
  - [x] https://github.com/kubernetes-sigs/structured-merge-diff/pull/129
- [ ] Reduce the serialized size of the managedFields @jennybuckley 
  - [x] Write document/KEP? to describe new format/approach
  - [x] Generate a map of field names to numbers **help wanted**
  - [ ] Implement the new serialization/deserialization format
  - [ ] Replace field names with integers to further reduce size
  - [ ] Test implementation
  - [ ] Document new format
- [ ] Test scalability with 50% of requests tracking managedFIelds
- [ ] Remove managedFIelds from very large objects (close to etcd object size limit)

### Declarative Manager
- [ ] Allow setting "fieldManager" declaratively (add it as a field): KEP (https://github.com/kubernetes/enhancements/pull/923), #75917 @kwiesmueller 

### Topology
- [ ] Understand, test and document how topology changes affect types compatibility (e.g. setting a list from atomic to associative-list, and many other combinations)
- [ ] Document CRD can use list-type and list-map-keys https://github.com/kubernetes-sigs/structured-merge-diff/issues/115 @apelisse
- [ ] API user targeted documentation (what is an asso. list and why) https://github.com/kubernetes/website/issues/16725 @apelisse
- [ ] Update KEP to explain `x-kubernetes-list-type` and other markers @apelisse

### Documentation
- [ ] Write documentation re: PATCH content type changes (document wire format)

### Miscellaneous
- [ ] Return code if Apply didn't change the object: https://github.com/kubernetes/kubernetes/issues/85750
- [ ] Find out what to do for objects that go over the size limit BECAUSE of SSA
- [ ] Add listType validation (set, maps) to CRDs even if SSA is disabled #84724
- [ ] Add `Apply()` to client-go (and potentially other clients) @joshmsamuels 
- [ ] Add apply functions to kubebuilder https://github.com/kubernetes-sigs/controller-runtime/issues/347 @mariantalla 
- [ ] Scale sub-resource doesn't update managedFields for replicas: #82046 @julianvmodesto  @mariantalla 
- [ ] server-side apply takes ownership of fields that don't get set due to status wiping #75564 https://github.com/kubernetes/enhancements/pull/1123 @kwiesmueller @joshmsamuels https://github.com/kubernetes-sigs/structured-merge-diff/pull/133
- [ ] Skip `proto.Schema` and go from v3 to smd schema directly
   - [ ] Surface schema parsing errors from CRD handler to users who don't understand why their CRD isn't being handled by apply like they expect (Related to #82438)
- [ ] Defaulted associative keys are missing @jennybuckley https://github.com/kubernetes-sigs/structured-merge-diff/pull/83
- [ ] Integrate with controller-runtime: https://github.com/kubernetes-sigs/controller-runtime/issues/347
- [ ] Merge annotations available in kube-builder https://github.com/kubernetes-sigs/controller-runtime/issues/638 @apelisse 
- [ ] Decide what to do with mutating admission controllers @kwiesmueller #78469
- [ ] Validation ratcheting: https://github.com/kubernetes/kubernetes/issues/64841#issuecomment-413263824
- [ ] Think about removing feature branch altogether, or archive it somehow
- [ ] Make a set of test cases in an easy-to-consume place (separate package?) so it's easy to test in both integration and e2e. (from [this comment](https://github.com/kubernetes/kubernetes/blob/master/test/integration/apiserver/apply/apply_test.go#L57))

### Unions and Immutability
- [ ] Design and implement API Union types: https://github.com/kubernetes/enhancements/pull/926/, https://github.com/kubernetes-sigs/structured-merge-diff/pull/72 #77370 #77770 
- [ ] Immutable Fields API: @sttts  @jpbetz  https://github.com/kubernetes/enhancements/pull/1099
- [ ] In `kube-openapi/schemaconv`, we could do a better job of detecting bad unions **help wanted**

### Declarative Field Removal
- [ ] Design a way to remove specific fields or values

### Enabling SSA by default on Kubectl
- [ ] KEP Review: https://github.com/kubernetes/enhancements/pull/1382
- [ ] Bug: getting conflict when creating with apply an atomic list @jennybuckley 
- [ ] Handle default values that are optional but  part of a key  (`protocol` in `containerPorts`) 
- [ ] Age-out pathway: how to prevent cruft: design doc
- [ ] Support upgrade from lastApplied annotation to managedFields (outlined in [this doc](https://goo.gl/fg7tUW#heading=h.gf5xewvom24o))
- [ ] How do people start using the feature: coming from client-side apply

## Completed/Canceled
- ~[ ] Consider removing union logic in update pathways (manager identification would need to always be unique)~ 
- [x] Serialization of fieldsets in managedFields should always be the same #82042
- [x] Move FieldManager test where it'll be less flaky: https://github.com/kubernetes/kubernetes/pull/78738/files#r317326938 @tedyu #82135
- [x] Fix int or float bug when deserializing to Object @kwiesmueller
- [x] Update API docs because they mention "Alpha" everywhere @apelisse #82548
- [x] Fail if apply specifies `ManagedFields` and/or document if it does, and write a test @joshmsamuels #81453
- [x] Improve field manager semantics documentation: what does owning mean, for lists, across versions, etc... https://github.com/kubernetes/website/pull/15948
- [x] Use the schema provided by a CRD if it exists (from [this comment](https://github.com/kubernetes/kubernetes/blob/master/staging/src/k8s.io/apiserver/pkg/endpoints/handlers/fieldmanager/internal/typeconverter.go#L46)) @jennybuckley #77354
  - [x] Add a test for applying CRDs
- [x] Make sure we don't write to etcd when applying has no changes: verified locally, but needs test #81673
- [x] Verify and maybe document? how to wipe out managedFields: should we have a sub-resources to change managedFields? @kwiesmueller https://github.com/kubernetes/website/pull/15700/
- [x] Scalability issue with server-side apply enabled: #76219 https://github.com/kubernetes/enhancements/pull/1110 @jennybuckley @apelisse @lavalamp  
  - [ ] ~Hide `ManagedFields` by default: @apelisse https://github.com/kubernetes/enhancements/pull/1081/~ @apelisse We've decided not to do that.
  - [x] Write benchmarks for each step and for the full-flow
  - [x] Write issue with scalability findings and possible solutions
  - [x] Make API change
  - [x] Would it make sense to use "RawMessage", does it have a protobuf equivalent?
  - [x] Consider etcd storage limits (objects close to maximum)
- [ ] ~RBAC for dry-run (ability to dry-run without write permission): https://github.com/kubernetes/enhancements/pull/893~ @apelisse 
- [x] Kubectl server-side apply shouldn't fallback on client-side apply if not available. TODO: check if this is done. @joshmsamuels 
- [x] Not fail on update failures (and monitor the errors) @apelisse #77987
- [x] Handle conversions for managedFields for versions that are no longer served (https://github.com/kubernetes/kubernetes/issues/77519)
- [x] Add cross group/version test: https://github.com/kubernetes/kubernetes/pull/75302#issuecomment-472227136: @julianvmodesto https://github.com/kubernetes/kubernetes/pull/76468
- [x] Define openapi future strategy (https://github.com/kubernetes/kube-openapi/pull/147#issuecomment-466549008): @jennybuckley 
- [x] Handle RawExtension / CRDs more consistently, as non-atomic Untyped (https://github.com/kubernetes-sigs/structured-merge-diff/pull/71)
- [x] Merge feature-serverside-apply branch into master (#72947)
- [x] Test-grid stayed green after the PR was merged.
- [x] Make sure no tests are broken when the feature is enabled (#73763)
- [x] Fix apply for RawExtensions by updating kube-openapi vendor (https://github.com/kubernetes/kubernetes/pull/71223)
- [x] Handle removed API type versions correctly in managedFields (https://github.com/kubernetes-sigs/structured-merge-diff/pull/63)
- [x] Strip selected fields from managedFields (#73681)
- [x] Revert #73763 when https://github.com/kubernetes/kube-openapi/pull/133 is vendored in (#73974)
- [x] Kubectl doesn't print nice conflict errors because of json manager name (#73976)
- [x] Applying with server-side apply fails for Service (#73759, #73831)
- [x] Make sure forceAllowCreate works for all the custom storage implementations (#65925, might be the cause of #73759)
- [X] Update reviewers/approvers for the feature (#73865)
- [x] Changing container port doesn't remove dangling item (https://github.com/kubernetes-sigs/structured-merge-diff/pull/65)
- [x] Review existing test suite and improve it, add more tests! (https://github.com/kubernetes-sigs/structured-merge-diff/pull/64, https://github.com/kubernetes-sigs/structured-merge-diff/pull/69, https://github.com/kubernetes-sigs/structured-merge-diff/pull/68)
- [x] Strip additional fields from `FieldManager` (#74206)
- [x] Update vendor to pull in changes to smd (#74981)
- [x] Sort `ManagedFields` by `(operation_type, timestamp, manager)` (#74721, #75075)
- [x] Add monitoring for various endpoints/verbs/content-types (#74997)
- [x] Figure out where workflow IDs will come from (outlined in [this doc](https://docs.google.com/document/d/1hNYwQAKDig-ljS8jvV8WtVBssWfG_4WHrsLJgZg_wgQ/edit)) (~#74171~, #74760)
- [x] Fix versionconverter bug (#75151)
- [x] Explicitly check that patchObj is in the proper version (from [this comment](https://github.com/kubernetes/kubernetes/blob/master/staging/src/k8s.io/apiserver/pkg/endpoints/handlers/fieldmanager/fieldmanager.go#L155)) (#75135, #75157)
- [x] Preserve int/float distinction by not going through unstructured on patch bytes (#75277)
- [x] Release note and Documentation for new feature (https://github.com/kubernetes/website/pull/13077)

cc @apelisse @lavalamp @kwiesmueller 
/sig api-machinery