fix(kubelet): handle parsing of imageMaximumGCAge and imageMinimumGCAge in kubelet config

- add unit tests for image GC duration
- change the string type of the image GC field to metav1.Duration
- remove unnecessary comments

nodeup/pkg/model/kubelet.go

@@ -248,6 +248,12 @@ func buildKubeletComponentConfig(kubeletConfig *kops.KubeletConfigSpec, provider
 	if kubeletConfig.ShutdownGracePeriodCriticalPods != nil {
 		componentConfig.ShutdownGracePeriodCriticalPods = *kubeletConfig.ShutdownGracePeriodCriticalPods
 	}
+	if kubeletConfig.ImageMaximumGCAge != nil {
+		componentConfig.ImageMaximumGCAge = *kubeletConfig.ImageMaximumGCAge
+	}
+	if kubeletConfig.ImageMinimumGCAge != nil {
+		componentConfig.ImageMinimumGCAge = *kubeletConfig.ImageMinimumGCAge
+	}
 	componentConfig.MemorySwap.SwapBehavior = kubeletConfig.MemorySwapBehavior
 
 	s := runtime.NewScheme()

nodeup/pkg/model/kubelet_test.go

@@ -31,6 +31,7 @@ import (
 	"k8s.io/kops/pkg/apis/nodeup"
 	"k8s.io/kops/pkg/assets"
 	"k8s.io/kops/pkg/client/simple/vfsclientset"
+	"k8s.io/kops/pkg/flagbuilder"
 	"k8s.io/kops/pkg/pki"
 	"k8s.io/kops/pkg/testutils"
 	"k8s.io/kops/upup/pkg/fi"
@@ -399,6 +400,8 @@ func Test_BuildComponentConfigFile(t *testing.T) {
 	componentConfig := kops.KubeletConfigSpec{
 		ShutdownGracePeriod:             &metav1.Duration{Duration: 30 * time.Second},
 		ShutdownGracePeriodCriticalPods: &metav1.Duration{Duration: 10 * time.Second},
+		ImageMaximumGCAge:               &metav1.Duration{Duration: 30 * time.Hour},
+		ImageMinimumGCAge:               &metav1.Duration{Duration: 30 * time.Minute},
 	}
 
 	_, err := buildKubeletComponentConfig(&componentConfig, "")
@@ -406,3 +409,34 @@ func Test_BuildComponentConfigFile(t *testing.T) {
 		t.Errorf("Failed to build component config file: %v", err)
 	}
 }
+
+func Test_Kubelet_BuildFlags(t *testing.T) {
+	grid := []struct {
+		config   kops.KubeletConfigSpec
+		expected string
+	}{
+		{
+			kops.KubeletConfigSpec{
+				ImageMaximumGCAge: &metav1.Duration{Duration: 30 * time.Hour},
+			},
+			"",
+		},
+		{
+			kops.KubeletConfigSpec{
+				ImageMinimumGCAge: &metav1.Duration{Duration: 30 * time.Minute},
+			},
+			"",
+		},
+	}
+
+	for _, g := range grid {
+		actual, err := flagbuilder.BuildFlags(&g.config)
+		if err != nil {
+			t.Errorf("error building flags for %v: %v", g.config, err)
+			continue
+		}
+		if actual != g.expected {
+			t.Errorf("flags did not match.  actual=%q expected=%q", actual, g.expected)
+		}
+	}
+}

pkg/apis/kops/componentconfig.go

@@ -132,11 +132,11 @@ type KubeletConfigSpec struct {
 	// computed (such as IPSEC).
 	NetworkPluginMTU *int32 `json:"networkPluginMTU,omitempty" flag:"network-plugin-mtu"`
 	// imageMinimumGCAge is the minimum age for an unused image before it is garbage collected. Default: "2m"
-	ImageMinimumGCAge *string `json:"imageMinimumGCAge,omitempty" flag:"image-minimum-gc-age"`
+	ImageMinimumGCAge *metav1.Duration `json:"imageMinimumGCAge,omitempty"`
 	// imageMaximumGCAge is the maximum age an image can be unused before it is garbage collected.
 	// The default of this field is "0s", which disables this field--meaning images won't be garbage
 	// collected based on being unused for too long. Default: "0s" (disabled)
-	ImageMaximumGCAge *string `json:"imageMaximumGCAge,omitempty" flag:"image-maximum-gc-age"`
+	ImageMaximumGCAge *metav1.Duration `json:"imageMaximumGCAge,omitempty"`
 	// ImageGCHighThresholdPercent is the percent of disk usage after which
 	// image garbage collection is always run.
 	ImageGCHighThresholdPercent *int32 `json:"imageGCHighThresholdPercent,omitempty" flag:"image-gc-high-threshold"`

pkg/apis/kops/v1alpha2/componentconfig.go

@@ -132,11 +132,11 @@ type KubeletConfigSpec struct {
 	// computed (such as IPSEC).
 	NetworkPluginMTU *int32 `json:"networkPluginMTU,omitempty" flag:"network-plugin-mtu"`
 	// imageMinimumGCAge is the minimum age for an unused image before it is garbage collected. Default: "2m"
-	ImageMinimumGCAge *string `json:"imageMinimumGCAge,omitempty" flag:"image-minimum-gc-age"`
+	ImageMinimumGCAge *metav1.Duration `json:"imageMinimumGCAge,omitempty"`
 	// imageMaximumGCAge is the maximum age an image can be unused before it is garbage collected.
 	// The default of this field is "0s", which disables this field--meaning images won't be garbage
 	// collected based on being unused for too long. Default: "0s" (disabled)
-	ImageMaximumGCAge *string `json:"imageMaximumGCAge,omitempty" flag:"image-maximum-gc-age"`
+	ImageMaximumGCAge *metav1.Duration `json:"imageMaximumGCAge,omitempty"`
 	// ImageGCHighThresholdPercent is the percent of disk usage after which
 	// image garbage collection is always run.
 	ImageGCHighThresholdPercent *int32 `json:"imageGCHighThresholdPercent,omitempty" flag:"image-gc-high-threshold"`

pkg/apis/kops/v1alpha2/zz_generated.deepcopy.go

@@ -4197,12 +4197,12 @@ func (in *KubeletConfigSpec) DeepCopyInto(out *KubeletConfigSpec) {
 	}
 	if in.ImageMinimumGCAge != nil {
 		in, out := &in.ImageMinimumGCAge, &out.ImageMinimumGCAge
-		*out = new(string)
+		*out = new(v1.Duration)
 		**out = **in
 	}
 	if in.ImageMaximumGCAge != nil {
 		in, out := &in.ImageMaximumGCAge, &out.ImageMaximumGCAge
-		*out = new(string)
+		*out = new(v1.Duration)
 		**out = **in
 	}
 	if in.ImageGCHighThresholdPercent != nil {

pkg/apis/kops/v1alpha3/componentconfig.go

@@ -131,11 +131,11 @@ type KubeletConfigSpec struct {
 	// computed (such as IPSEC).
 	NetworkPluginMTU *int32 `json:"networkPluginMTU,omitempty" flag:"network-plugin-mtu"`
 	// imageMinimumGCAge is the minimum age for an unused image before it is garbage collected. Default: "2m"
-	ImageMinimumGCAge *string `json:"imageMinimumGCAge,omitempty" flag:"image-minimum-gc-age"`
+	ImageMinimumGCAge *metav1.Duration `json:"imageMinimumGCAge,omitempty"`
 	// imageMaximumGCAge is the maximum age an image can be unused before it is garbage collected.
 	// The default of this field is "0s", which disables this field--meaning images won't be garbage
 	// collected based on being unused for too long. Default: "0s" (disabled)
-	ImageMaximumGCAge *string `json:"imageMaximumGCAge,omitempty" flag:"image-maximum-gc-age"`
+	ImageMaximumGCAge *metav1.Duration `json:"imageMaximumGCAge,omitempty"`
 	// ImageGCHighThresholdPercent is the percent of disk usage after which
 	// image garbage collection is always run.
 	ImageGCHighThresholdPercent *int32 `json:"imageGCHighThresholdPercent,omitempty" flag:"image-gc-high-threshold"`

pkg/apis/kops/v1alpha3/zz_generated.deepcopy.go

@@ -4176,12 +4176,12 @@ func (in *KubeletConfigSpec) DeepCopyInto(out *KubeletConfigSpec) {
 	}
 	if in.ImageMinimumGCAge != nil {
 		in, out := &in.ImageMinimumGCAge, &out.ImageMinimumGCAge
-		*out = new(string)
+		*out = new(v1.Duration)
 		**out = **in
 	}
 	if in.ImageMaximumGCAge != nil {
 		in, out := &in.ImageMaximumGCAge, &out.ImageMaximumGCAge
-		*out = new(string)
+		*out = new(v1.Duration)
 		**out = **in
 	}
 	if in.ImageGCHighThresholdPercent != nil {

pkg/apis/kops/zz_generated.deepcopy.go

@@ -4279,12 +4279,12 @@ func (in *KubeletConfigSpec) DeepCopyInto(out *KubeletConfigSpec) {
 	}
 	if in.ImageMinimumGCAge != nil {
 		in, out := &in.ImageMinimumGCAge, &out.ImageMinimumGCAge
-		*out = new(string)
+		*out = new(v1.Duration)
 		**out = **in
 	}
 	if in.ImageMaximumGCAge != nil {
 		in, out := &in.ImageMaximumGCAge, &out.ImageMaximumGCAge
-		*out = new(string)
+		*out = new(v1.Duration)
 		**out = **in
 	}
 	if in.ImageGCHighThresholdPercent != nil {