KEP 4210: add a feature gate

Signed-off-by: Peter Hunt <[email protected]>

keps/sig-node/4210-max-image-gc-age/README.md

@@ -66,7 +66,7 @@ Items marked with (R) are required *prior to targeting to a milestone / release*
 ## Summary
 
 Add an option ImageMaximumGCAge, which allows an admin to specify a time after which unused images will be garbage collected
-by the Kubelet, regardless of disk usage.
+by the Kubelet, regardless of disk usage, as well as an associated feature gate to toggle the behavior.
 
 ## Motivation
 
@@ -81,7 +81,7 @@ through the disk usage condition, they will needlessly occupy disk space before
 
 ### Goals
 
-- Introduce an option to the Kubelet ImageMaximumGCAge
+- Introduce an option to the Kubelet ImageMaximumGCAge and a feature gate ImageMaximumGCAge
 
 ### Non-Goals
 
@@ -115,6 +115,8 @@ The proposal of this KEP is to add an option to the KubeletConfiguration object
 
 To begin, this option will be set to 0, which will be interpreted as "disabled". In the future, a more reasonable default may be chosen.
 
+This option will only be adhered to if the feature gate ImageMaximumGCAge is configured for the Kubelet.
+
 ### User Stories (Optional)
 
 #### Story 1
@@ -238,18 +240,15 @@ Version skew is not a worry assuming the internal Kubelet changes are synchroniz
 
 ###### How can this feature be enabled / disabled in a live cluster?
 
-- [ ] Feature gate (also fill in values in `kep.yaml`)
-  - Feature gate name:
-  - Components depending on the feature gate:
-- [x] Other
+- [x] Feature gate (also fill in values in `kep.yaml`)
+  - Feature gate name: ImageGCMaximumAge
+  - Components depending on the feature gate: kubelet
+- [ ] Other
   - Describe the mechanism:
-    - Kubelet configuration field
   - Will enabling / disabling the feature require downtime of the control
     plane?
-    - No, it's a kubelet only configuration
   - Will enabling / disabling the feature require downtime or reprovisioning
     of a node?
-    - Potentially, to restart the Kubelet.
 
 ###### Does enabling the feature change any default behavior?
 

keps/sig-node/4210-max-image-gc-age/kep.yaml

@@ -28,6 +28,7 @@ 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: ImageGCMaximumAge
 disable-supported: true
 
 # The following PRR answers are required at beta release