Fix serialization of EnforceNodeAllocatable

EnforceNodeAllocatable being `nil` and `[]` are treated in different ways by kubelet. Namely, `nil` is replaced with `[]string{"pods"}` by the defaulting mechanism. E.g. if you run kubelet in Docker-in-Docker environment you may need to run it with the following options: `--cgroups-per-qos=false --enforce-node-allocatable=` (this corresponds to EnforceNodeAllocatable being empty array and not null) If you then grab kubelet configuration via /configz and try to reuse it for dynamic kubelet config, kubelet will think that EnforceNodeAllocatable is null, failing to run in the Docker-in-Docker environment. Encountered this while updating Virtlet for Kubernetes 1.6 (the dev environment is based on kubeadm-dind-cluster)

Fix serialization of EnforceNodeAllocatable
ef85747e · Ivan Shvedunov · ff3a847d · ef85747e · ef85747e
Commit ef85747e authored Apr 18, 2017 by Ivan Shvedunov
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Showing with 6 additions and 2 deletions

types.go pkg/apis/componentconfig/v1alpha1/types.go +1 -1

zz_generated.conversion.go pkg/apis/componentconfig/v1alpha1/zz_generated.conversion.go +5 -1

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--- a/pkg/apis/componentconfig/v1alpha1/types.go
+++ b/pkg/apis/componentconfig/v1alpha1/types.go
@@ -601,7 +601,7 @@ type KubeletConfiguration struct {
 	// This flag specifies the various Node Allocatable enforcements that Kubelet needs to perform.
 	// This flag accepts a list of options. Acceptible options are `pods`, `system-reserved` & `kube-reserved`.
 	// Refer to [Node Allocatable](https://github.com/kubernetes/community/blob/master/contributors/design-proposals/node-allocatable.md) doc for more information.
-	EnforceNodeAllocatable []string `json:"enforceNodeAllocatable,omitempty"`
+	EnforceNodeAllocatable []string `json:"enforceNodeAllocatable"`
 	// This flag, if set, will avoid including `EvictionHard` limits while computing Node Allocatable.
 	// Refer to [Node Allocatable](https://github.com/kubernetes/community/blob/master/contributors/design-proposals/node-allocatable.md) doc for more information.
 	ExperimentalNodeAllocatableIgnoreEvictionThreshold bool `json:"experimentalNodeAllocatableIgnoreEvictionThreshold,omitempty"`

--- a/pkg/apis/componentconfig/v1alpha1/zz_generated.conversion.go
+++ b/pkg/apis/componentconfig/v1alpha1/zz_generated.conversion.go
@@ -729,7 +729,11 @@ func autoConvert_componentconfig_KubeletConfiguration_To_v1alpha1_KubeletConfigu
 	out.KubeReserved = *(*map[string]string)(unsafe.Pointer(&in.KubeReserved))
 	out.SystemReservedCgroup = in.SystemReservedCgroup
 	out.KubeReservedCgroup = in.KubeReservedCgroup
-	out.EnforceNodeAllocatable = *(*[]string)(unsafe.Pointer(&in.EnforceNodeAllocatable))
+	if in.EnforceNodeAllocatable == nil {
+		out.EnforceNodeAllocatable = make([]string, 0)
+	} else {
+		out.EnforceNodeAllocatable = *(*[]string)(unsafe.Pointer(&in.EnforceNodeAllocatable))
+	}
 	out.ExperimentalNodeAllocatableIgnoreEvictionThreshold = in.ExperimentalNodeAllocatableIgnoreEvictionThreshold
 	return nil
 }