Merge pull request #24047 from derekwaynecarr/reuse_summary_provider

Automatic merge from submit-queue

Expose SummaryProvider for reuse by other parts of kubelet

To support out of resource killing in the kubelet, we will introduce a new top-level module that will ensure node stability by checking if eviction thresholds have been met for memory and file-system usage on the node.  In addition, it will then need information about pod memory and disk usage in order to make an eviction selection.  Currently, this information is collected in `SummaryProvider` but it's hidden away and not available for re-use by other top-level modules of the kubelet.  This initial refactor adds the ability to get summary stat information from the `ResourceAnalyzer` so it can be reused by other top-level modules.

I suspect we will further re-factor this area as code evolves, but this unblocks further progress on out-of-resource killing.

/cc @vishh @timothysc @kubernetes/sig-node @kubernetes/rh-cluster-infra

pkg/kubelet/server/stats/handler.go

@@ -55,8 +55,8 @@ type handler struct {
 	summaryProvider SummaryProvider
 }
 
-func CreateHandlers(provider StatsProvider, resourceAnalyzer ResourceAnalyzer) *restful.WebService {
-	h := &handler{provider, NewSummaryProvider(provider, resourceAnalyzer)}
+func CreateHandlers(provider StatsProvider, summaryProvider SummaryProvider) *restful.WebService {
+	h := &handler{provider, summaryProvider}
 
 	ws := &restful.WebService{}
 	ws.Path("/stats/").

pkg/kubelet/server/stats/resource_analyzer.go

@@ -23,18 +23,22 @@ type ResourceAnalyzer interface {
 	Start()
 
 	fsResourceAnalyzerInterface
+	SummaryProvider
 }
 
 // resourceAnalyzer implements ResourceAnalyzer
 type resourceAnalyzer struct {
 	*fsResourceAnalyzer
+	SummaryProvider
 }
 
 var _ ResourceAnalyzer = &resourceAnalyzer{}
 
 // NewResourceAnalyzer returns a new ResourceAnalyzer
 func NewResourceAnalyzer(statsProvider StatsProvider, calVolumeFrequency time.Duration) ResourceAnalyzer {
-	return &resourceAnalyzer{newFsResourceAnalyzer(statsProvider, calVolumeFrequency)}
+	fsAnalyzer := newFsResourceAnalyzer(statsProvider, calVolumeFrequency)
+	summaryProvider := NewSummaryProvider(statsProvider, fsAnalyzer)
+	return &resourceAnalyzer{fsAnalyzer, summaryProvider}
 }
 
 // Start starts background functions necessary for the ResourceAnalyzer to function

pkg/kubelet/server/stats/summary.go

@@ -43,17 +43,17 @@ type SummaryProvider interface {
 }
 
 type summaryProviderImpl struct {
-	provider         StatsProvider
-	resourceAnalyzer ResourceAnalyzer
+	provider           StatsProvider
+	fsResourceAnalyzer fsResourceAnalyzerInterface
 }
 
 var _ SummaryProvider = &summaryProviderImpl{}
 
 // NewSummaryProvider returns a new SummaryProvider
-func NewSummaryProvider(statsProvider StatsProvider, resourceAnalyzer ResourceAnalyzer) SummaryProvider {
+func NewSummaryProvider(statsProvider StatsProvider, fsResourceAnalyzer fsResourceAnalyzerInterface) SummaryProvider {
 	stackBuff := []byte{}
 	runtime.Stack(stackBuff, false)
-	return &summaryProviderImpl{statsProvider, resourceAnalyzer}
+	return &summaryProviderImpl{statsProvider, fsResourceAnalyzer}
 }
 
 // Get implements the SummaryProvider interface
@@ -84,18 +84,18 @@ func (sp *summaryProviderImpl) Get() (*stats.Summary, error) {
 		return nil, err
 	}
 
-	sb := &summaryBuilder{sp.resourceAnalyzer, node, nodeConfig, rootFsInfo, imageFsInfo, infos}
+	sb := &summaryBuilder{sp.fsResourceAnalyzer, node, nodeConfig, rootFsInfo, imageFsInfo, infos}
 	return sb.build()
 }
 
 // summaryBuilder aggregates the datastructures provided by cadvisor into a Summary result
 type summaryBuilder struct {
-	resourceAnalyzer ResourceAnalyzer
-	node             *api.Node
-	nodeConfig       cm.NodeConfig
-	rootFsInfo       cadvisorapiv2.FsInfo
-	imageFsInfo      cadvisorapiv2.FsInfo
-	infos            map[string]cadvisorapiv2.ContainerInfo
+	fsResourceAnalyzer fsResourceAnalyzerInterface
+	node               *api.Node
+	nodeConfig         cm.NodeConfig
+	rootFsInfo         cadvisorapiv2.FsInfo
+	imageFsInfo        cadvisorapiv2.FsInfo
+	infos              map[string]cadvisorapiv2.ContainerInfo
 }
 
 // build returns a Summary from aggregating the input data
@@ -222,7 +222,7 @@ func (sb *summaryBuilder) buildSummaryPods() []stats.PodStats {
 	for _, podStats := range podToStats {
 		// Lookup the volume stats for each pod
 		podUID := types.UID(podStats.PodRef.UID)
-		if vstats, found := sb.resourceAnalyzer.GetPodVolumeStats(podUID); found {
+		if vstats, found := sb.fsResourceAnalyzer.GetPodVolumeStats(podUID); found {
 			podStats.VolumeStats = vstats.Volumes
 		}
 		result = append(result, *podStats)