move minGCAge to ImageGCPolicy and make it configurable

cmd/kubelet/app/options/options.go

@@ -87,6 +87,7 @@ func NewKubeletServer() *KubeletServer {
 			HostPIDSources:              kubetypes.AllSource,
 			HostIPCSources:              kubetypes.AllSource,
 			HTTPCheckFrequency:          unversioned.Duration{20 * time.Second},
+			ImageMinimumGCAge:           unversioned.Duration{2 * time.Minute},
 			ImageGCHighThresholdPercent: 90,
 			ImageGCLowThresholdPercent:  80,
 			LowDiskSpaceThresholdMB:     256,
@@ -182,6 +183,7 @@ func (s *KubeletServer) AddFlags(fs *pflag.FlagSet) {
 	fs.DurationVar(&s.NodeStatusUpdateFrequency.Duration, "node-status-update-frequency", s.NodeStatusUpdateFrequency.Duration, "Specifies how often kubelet posts node status to master. Note: be cautious when changing the constant, it must work with nodeMonitorGracePeriod in nodecontroller. Default: 10s")
 	bindableNodeLabels := util.ConfigurationMap(s.NodeLabels)
 	fs.Var(&bindableNodeLabels, "node-labels", "<Warning: Alpha feature> Labels to add when registering the node in the cluster.  Labels must are key=value pairs seperated by ','.")
+	fs.DurationVar(&s.ImageMinimumGCAge.Duration, "minimum-image-ttl-duration", s.ImageMinimumGCAge.Duration, "Minimum age for a unused image before it is garbage collected.  Examples: '300ms', '10s' or '2h45m'. Default: '2m'")
 	fs.IntVar(&s.ImageGCHighThresholdPercent, "image-gc-high-threshold", s.ImageGCHighThresholdPercent, "The percent of disk usage after which image garbage collection is always run. Default: 90%")
 	fs.IntVar(&s.ImageGCLowThresholdPercent, "image-gc-low-threshold", s.ImageGCLowThresholdPercent, "The percent of disk usage before which image garbage collection is never run. Lowest disk usage to garbage collect to. Default: 80%")
 	fs.IntVar(&s.LowDiskSpaceThresholdMB, "low-diskspace-threshold-mb", s.LowDiskSpaceThresholdMB, "The absolute free disk space, in MB, to maintain. When disk space falls below this threshold, new pods would be rejected. Default: 256")

cmd/kubelet/app/server.go

@@ -154,6 +154,7 @@ func UnsecuredKubeletConfig(s *options.KubeletServer) (*KubeletConfig, error) {
 	}
 
 	imageGCPolicy := kubelet.ImageGCPolicy{
+		MinAge:               s.ImageMinimumGCAge.Duration,
 		HighThresholdPercent: s.ImageGCHighThresholdPercent,
 		LowThresholdPercent:  s.ImageGCLowThresholdPercent,
 	}

docs/admin/kubelet.md

@@ -116,6 +116,7 @@ kubelet
       --maximum-dead-containers=100: Maximum number of old instances of containers to retain globally.  Each container takes up some disk space.  Default: 100.
       --maximum-dead-containers-per-container=2: Maximum number of old instances to retain per container.  Each container takes up some disk space.  Default: 2.
       --minimum-container-ttl-duration=1m0s: Minimum age for a finished container before it is garbage collected.  Examples: '300ms', '10s' or '2h45m'
+      --minimum-image-ttl-duration=2m0s: Minimum age for a unused image before it is garbage collected.  Examples: '300ms', '10s' or '2h45m'. Default: '2m'
       --network-plugin="": <Warning: Alpha feature> The name of the network plugin to be invoked for various events in kubelet/pod lifecycle
       --network-plugin-dir="/usr/libexec/kubernetes/kubelet-plugins/net/exec/": <Warning: Alpha feature> The full path of the directory in which to search for network plugins
       --node-ip="": IP address of the node. If set, kubelet will use this IP address for the node
@@ -151,7 +152,7 @@ kubelet
       --volume-stats-agg-period=1m0s: Specifies interval for kubelet to calculate and cache the volume disk usage for all pods and volumes.  To disable volume calculations, set to 0.  Default: '1m'
 ```
 
-###### Auto generated by spf13/cobra on 12-Feb-2016
+###### Auto generated by spf13/cobra on 15-Feb-2016
 
 
 <!-- BEGIN MUNGE: GENERATED_ANALYTICS -->

hack/verify-flags/known-flags.txt

@@ -229,6 +229,7 @@ min-pr-number
 min-request-timeout
 min-resync-period
 minimum-container-ttl-duration
+minimum-image-ttl-duration
 minion-max-log-age
 minion-max-log-backups
 minion-max-log-size

pkg/apis/componentconfig/types.go

@@ -197,6 +197,9 @@ type KubeletConfiguration struct {
 	// status to master. Note: be cautious when changing the constant, it
 	// must work with nodeMonitorGracePeriod in nodecontroller.
 	NodeStatusUpdateFrequency unversioned.Duration `json:"nodeStatusUpdateFrequency"`
+	// minimumGCAge is the minimum age for a unused image before it is
+	// garbage collected.
+	ImageMinimumGCAge unversioned.Duration `json:"imageMinimumGCAge"`
 	// imageGCHighThresholdPercent is the percent of disk usage after which
 	// image garbage collection is always run.
 	ImageGCHighThresholdPercent int `json:"imageGCHighThresholdPercent"`

pkg/kubelet/image_manager.go

@@ -32,10 +32,6 @@ import (
 	"k8s.io/kubernetes/pkg/util/wait"
 )
 
-const (
-	defaultGCAge = time.Minute * 1
-)
-
 // Manages lifecycle of all images.
 //
 // Implementation is thread-safe.
@@ -62,6 +58,9 @@ type ImageGCPolicy struct {
 	// Any usage below this threshold will never trigger garbage collection.
 	// This is the lowest threshold we will try to garbage collect to.
 	LowThresholdPercent int
+
+	// Minimum age at which a image can be garbage collected.
+	MinAge time.Duration
 }
 
 type realImageManager struct {
@@ -75,10 +74,6 @@ type realImageManager struct {
 	// The image garbage collection policy in use.
 	policy ImageGCPolicy
 
-	// Minimum age at which a image can be garbage collected, zero for no limit.
-	// TODO(mqliang): move it to ImageGCPolicy and make it configurable
-	minAge time.Duration
-
 	// cAdvisor instance.
 	cadvisor cadvisor.Interface
 
@@ -118,7 +113,6 @@ func newImageManager(runtime container.Runtime, cadvisorInterface cadvisor.Inter
 	im := &realImageManager{
 		runtime:      runtime,
 		policy:       policy,
-		minAge:       defaultGCAge,
 		imageRecords: make(map[string]*imageRecord),
 		cadvisor:     cadvisorInterface,
 		recorder:     recorder,
@@ -279,7 +273,8 @@ func (im *realImageManager) freeSpace(bytesToFree int64, freeTime time.Time) (in
 
 		// Avoid garbage collect the image if the image is not old enough.
 		// In such a case, the image may have just been pulled down, and will be used by a container right away.
-		if freeTime.Sub(image.firstDetected) < im.minAge {
+
+		if freeTime.Sub(image.firstDetected) < im.policy.MinAge {
 			continue
 		}
 

pkg/kubelet/image_manager_test.go

@@ -38,7 +38,6 @@ func newRealImageManager(policy ImageGCPolicy) (*realImageManager, *container.Fa
 	return &realImageManager{
 		runtime:      fakeRuntime,
 		policy:       policy,
-		minAge:       0,
 		imageRecords: make(map[string]*imageRecord),
 		cadvisor:     mockCadvisor,
 		recorder:     &record.FakeRecorder{},
@@ -406,13 +405,13 @@ func TestGarbageCollectImageNotOldEnough(t *testing.T) {
 	policy := ImageGCPolicy{
 		HighThresholdPercent: 90,
 		LowThresholdPercent:  80,
+		MinAge:               time.Minute * 1,
 	}
 	fakeRuntime := &container.FakeRuntime{}
 	mockCadvisor := new(cadvisor.Mock)
 	manager := &realImageManager{
 		runtime:      fakeRuntime,
 		policy:       policy,
-		minAge:       defaultGCAge,
 		imageRecords: make(map[string]*imageRecord),
 		cadvisor:     mockCadvisor,
 		recorder:     &record.FakeRecorder{},
@@ -443,7 +442,7 @@ func TestGarbageCollectImageNotOldEnough(t *testing.T) {
 	assert.Len(fakeRuntime.ImageList, 2)
 
 	// move clock by minAge duration, then 1 image will be garbage collected
-	fakeClock.Step(manager.minAge)
+	fakeClock.Step(policy.MinAge)
 	spaceFreed, err = manager.freeSpace(1024, fakeClock.Now())
 	require.NoError(t, err)
 	assert.EqualValues(1024, spaceFreed)