KEP-2485: Production Readiness Review Questionnaire

Author: chrishenzie

keps/sig-storage/2485-read-write-once-pod-pv-access-mode/README.md

@@ -728,15 +728,13 @@ This section must be completed when targeting alpha to a release.
 Pick one of these and delete the rest.
 -->
 
-- [ ] Feature gate (also fill in values in `kep.yaml`)
-  - Feature gate name:
+- [X] Feature gate (also fill in values in `kep.yaml`)
+  - Feature gate name: ReadWriteOncePod
   - Components depending on the feature gate:
-- [ ] Other
-  - Describe the mechanism:
-  - Will enabling / disabling the feature require downtime of the control
-    plane?
-  - Will enabling / disabling the feature require downtime or reprovisioning
-    of a node? (Do not assume `Dynamic Kubelet Config` feature is enabled).
+    - kube-apiserver
+    - kube-controller-manager
+    - kube-scheduler
+    - kubelet
 
 ###### Does enabling the feature change any default behavior?
 
@@ -745,6 +743,8 @@ Any change of default behavior may be surprising to users or break existing
 automations, so be extremely careful here.
 -->
 
+No.
+
 ###### Can the feature be disabled once it has been enabled (i.e. can we roll back the enablement)?
 
 <!--
@@ -754,8 +754,16 @@ feature, can it break the existing applications?).
 NOTE: Also set `disable-supported` to `true` or `false` in `kep.yaml`.
 -->
 
+When the feature gate is disabled, existing ReadWriteOncePod volumes will
+continue working. The only allowed operation will be the deletion of
+ReadWriteOncePod volumes.
+
 ###### What happens if we reenable the feature if it was previously rolled back?
 
+Any existing ReadWriteOncePod and ReadWriteOnce volumes will continue working.
+Upon re-enabling of the feature gate, users can begin creating ReadWriteOncePod
+volumes again.
+
 ###### Are there any tests for feature enablement/disablement?
 
 <!--
@@ -765,6 +773,10 @@ with and without the feature, are necessary. At the very least, think about
 conversion tests if API types are being modified.
 -->
 
+There will be unit test coverage for API validation and mount behavior with the
+feature gate enabled and disabled. There will also be end to end test coverage
+for mount behavior (if the the feature gate is enabled).
+
 ### Rollout, Upgrade and Rollback Planning
 
 <!--
@@ -895,6 +907,8 @@ Focusing mostly on:
     heartbeats, leader election, etc.)
 -->
 
+No.
+
 ###### Will enabling / using this feature result in introducing new API types?
 
 <!--
@@ -904,6 +918,12 @@ Describe them, providing:
   - Supported number of objects per namespace (for namespace-scoped objects)
 -->
 
+No, it will introduce a new "ReadWriteOncePod" value for the
+PersistentVolumeAccessMode type, added to the [internal] and [v1] APIs.
+
+[internal]: https://github.com/kubernetes/kubernetes/blob/v1.21.0/pkg/apis/core/types.go#L503-L514
+[v1]: https://github.com/kubernetes/kubernetes/blob/v1.21.0/staging/src/k8s.io/api/core/v1/types.go#L556-L565
+
 ###### Will enabling / using this feature result in any new calls to the cloud provider?
 
 <!--
@@ -912,6 +932,8 @@ Describe them, providing:
   - Estimated increase:
 -->
 
+No.
+
 ###### Will enabling / using this feature result in increasing size or count of the existing API objects?
 
 <!--
@@ -921,6 +943,8 @@ Describe them, providing:
   - Estimated amount of new objects: (e.g., new Object X for every existing Pod)
 -->
 
+No.
+
 ###### Will enabling / using this feature result in increasing time taken by any operations covered by existing SLIs/SLOs?
 
 <!--
@@ -932,6 +956,8 @@ Think about adding additional work or introducing new steps in between
 [existing SLIs/SLOs]: https://git.k8s.io/community/sig-scalability/slos/slos.md#kubernetes-slisslos
 -->
 
+No.
+
 ###### Will enabling / using this feature result in non-negligible increase of resource usage (CPU, RAM, disk, IO, ...) in any components?
 
 <!--
@@ -944,6 +970,8 @@ This through this both in small and large cases, again with respect to the
 [supported limits]: https://git.k8s.io/community//sig-scalability/configs-and-limits/thresholds.md
 -->
 
+No, the solution will involve using the same ActualStateOfWorld cache in kubelet.
+
 ### Troubleshooting
 
 <!--

keps/sig-storage/2485-read-write-once-pod-pv-access-mode/kep.yaml

@@ -34,6 +34,12 @@ milestone:
 # The following PRR answers are required at alpha release
 # List the feature gate name and the components for which it must be enabled
 feature-gates:
+  - name: ReadWriteOncePod
+    components:
+      - kube-apiserver
+      - kube-controller-manager
+      - kube-scheduler
+      - kubelet
 disable-supported: true
 
 # The following PRR answers are required at beta release