• Determine approach and format for warnings:
  • determine when to emit warnings: on creation, on update that would change generation / spec
  • Use field.Path format
  • for deprecated values, indicate replacement, deprecation and target removal release
• Add warnings for deprecated fields
  • Pod templates
    • beta os/arch/zone/region labels in node selectors / affinity - Add field-level warning plumbing and add pod spec warnings #101688
    • alpha seccomp annotations (Add warning messages about deprecated seccomp annotation usage #94365) - Add field-level warning plumbing and add pod spec warnings #101688
    • alpha sysctl annotations (Promote sysctl annotations to fields #63717) - Add field-level warning plumbing and add pod spec warnings #101688
  • PersistentVolumeSpec
    • deprecated node labels in volume node affinity - add deprecated warning for node beta labels in pv/sc/rc/csi storage capacity #108554
  • StorageClass
    • deprecated node labels - add deprecated warning for node beta labels in pv/sc/rc/csi storage capacity #108554
  • CSIStorageCapacity
    • deprecated node labels - add deprecated warning for node beta labels in pv/sc/rc/csi storage capacity #108554
  • RuntimeClass
    • deprecated node labels - add deprecated warning for node beta labels in pv/sc/rc/csi storage capacity #108554
• Add warnings for known bad values
  • PVC, PV, PVC template in statefulset and inline ephemeral volume
    • fractional byte storage requests (PVCs specified with quantity containing suffix m are not counted in ResourceQuota and block ResourceQuota updates #94313)
  • Pod templates
    • fractional byte requests/limits - Add field-level warning plumbing and add pod spec warnings #101688
    • duplicate hostAliases (kubectl apply drops all hostAlias entries when removing a duplicate entry from an existing object #91670, kubectl apply (client-side) removes all entries when attempting to remove a single duplicated entry in a persisted object #58477) - Add field-level warning plumbing and add pod spec warnings #101688
    • duplicate imagePullSecrets (kubectl apply removes all imagePullSecrets when user attempts to remove duplicate secrets #91629, kubectl apply (client-side) removes all entries when attempting to remove a single duplicated entry in a persisted object #58477) - Add field-level warning plumbing and add pod spec warnings #101688
    • duplicate containers[*].env (this issue, Failed to create three way merge patch when container environment variable specified multiple times #86163, Deployment objects using optional envs with the same name are unexpectedly removed during updates - but exist out of the box #93266, kubectl apply (client-side) removes all entries when attempting to remove a single duplicated entry in a persisted object #58477) - Add field-level warning plumbing and add pod spec warnings #101688
    • duplicate volumes (kubectl apply admits Deployment with duplicate volumes then fails when renaming duplicate #78266, kubectl apply (client-side) removes all entries when attempting to remove a single duplicated entry in a persisted object #58477) - Add field-level warning plumbing and add pod spec warnings #101688
    • duplicate containers[*].ports (Container Ports for pods vanishing #86273, Duplicate ports in deployment results in non-deterministic port assignment #93952, kubectl apply (client-side) removes all entries when attempting to remove a single duplicated entry in a persisted object #58477)
    • pods setting both linux and windows options? (if multi-OS images are not possible. xref fix windows container root validate #92355 (comment))
    • imagePullSecrets or volume source entries with empty secret or configmap name (Kubelet fails to retrieve secret with empty name #99454 (comment))
  • Service
    • duplicate {port,protocol} items in ports list (apiserver allows duplicate service port #59119, kubectl apply (client-side) removes all entries when attempting to remove a single duplicated entry in a persisted object #58477, PATCH merges Services with same port, different protocol #47249)
  • ... issues linked from Validation Tightening is not Generally Possible #64841 (comment)

See:

• Warning mechanism for use of deprecated APIs enhancements#1693
• https://github.com/kubernetes/enhancements/tree/master/keps/sig-api-machinery/1693-warnings
• https://kubernetes.io/blog/2020/09/03/warnings/#future-possibilities
• kubectl apply (client-side) removes all entries when attempting to remove a single duplicated entry in a persisted object #58477

/assign
/sig api-machinery
/milestone v1.20
See:

• Warning mechanism for use of deprecated APIs enhancements#1693
• https://github.com/kubernetes/enhancements/tree/master/keps/sig-api-machinery/1693-warnings
• https://kubernetes.io/blog/2020/09/03/warnings/#future-possibilities
• kubectl apply (client-side) removes all entries when attempting to remove a single duplicated entry in a persisted object #58477

/assign
/sig api-machinery
/milestone v1.20
See:

• Warning mechanism for use of deprecated APIs enhancements#1693
• https://github.com/kubernetes/enhancements/tree/master/keps/sig-api-machinery/1693-warnings
• https://kubernetes.io/blog/2020/09/03/warnings/#future-possibilities
• kubectl apply (client-side) removes all entries when attempting to remove a single duplicated entry in a persisted object #58477

/assign
/sig api-machinery
/milestone v1.20