Add AllowSidecarResizePolicy to relax resize policy validation check of sidecar containers

pkg/api/pod/util.go

@@ -416,6 +416,8 @@ func GetValidationOptionsFromPodSpecAndMeta(podSpec, oldPodSpec *api.PodSpec, po
 		}
 
 		opts.AllowPodLifecycleSleepActionZeroValue = opts.AllowPodLifecycleSleepActionZeroValue || podLifecycleSleepActionZeroValueInUse(podSpec)
+		// If oldPod has resize policy set on the restartable init container, we must allow it
+		opts.AllowSidecarResizePolicy = hasRestartableInitContainerResizePolicy(oldPodSpec)
 	}
 	if oldPodMeta != nil && !opts.AllowInvalidPodDeletionCost {
 		// This is an update, so validate only if the existing object was valid.
@@ -1373,3 +1375,17 @@ func useOnlyRecursiveSELinuxChangePolicy(oldPodSpec *api.PodSpec) bool {
 	// No feature gate + no value in the old object -> only Recursive is allowed
 	return true
 }
+
+// hasRestartableInitContainerResizePolicy returns true if the pod spec is non-nil and
+// it has any init container with ContainerRestartPolicyAlways and non-nil ResizePolicy.
+func hasRestartableInitContainerResizePolicy(podSpec *api.PodSpec) bool {
+	if podSpec == nil {
+		return false
+	}
+	for _, c := range podSpec.InitContainers {
+		if IsRestartableInitContainer(&c) && len(c.ResizePolicy) > 0 {
+			return true
+		}
+	}
+	return false
+}