Include pod /etc/hosts in ephemeral storage calculation for eviction

Author: joelsmith

pkg/kubelet/eviction/BUILD

@@ -65,6 +65,7 @@ go_library(
         "//staging/src/k8s.io/api/core/v1:go_default_library",
         "//staging/src/k8s.io/apimachinery/pkg/api/resource:go_default_library",
         "//staging/src/k8s.io/apimachinery/pkg/apis/meta/v1:go_default_library",
+        "//staging/src/k8s.io/apimachinery/pkg/types:go_default_library",
         "//staging/src/k8s.io/apimachinery/pkg/util/clock:go_default_library",
         "//staging/src/k8s.io/apiserver/pkg/util/feature:go_default_library",
         "//staging/src/k8s.io/client-go/tools/record:go_default_library",

pkg/kubelet/eviction/eviction_manager.go

@@ -26,6 +26,7 @@ import (
 
 	v1 "k8s.io/api/core/v1"
 	"k8s.io/apimachinery/pkg/api/resource"
+	"k8s.io/apimachinery/pkg/types"
 	"k8s.io/apimachinery/pkg/util/clock"
 	utilfeature "k8s.io/apiserver/pkg/util/feature"
 	"k8s.io/client-go/tools/record"
@@ -98,6 +99,8 @@ type managerImpl struct {
 	thresholdNotifiers []ThresholdNotifier
 	// thresholdsLastUpdated is the last time the thresholdNotifiers were updated.
 	thresholdsLastUpdated time.Time
+	// etcHostsPath is a function that will get the etc-hosts file's path for a pod given its UID
+	etcHostsPath func(podUID types.UID) string
 }
 
 // ensure it implements the required interface
@@ -114,6 +117,7 @@ func NewManager(
 	recorder record.EventRecorder,
 	nodeRef *v1.ObjectReference,
 	clock clock.Clock,
+	etcHostsPath func(types.UID) string,
 ) (Manager, lifecycle.PodAdmitHandler) {
 	manager := &managerImpl{
 		clock:                        clock,
@@ -129,6 +133,7 @@ func NewManager(
 		thresholdsFirstObservedAt:    thresholdsObservedAt{},
 		dedicatedImageFs:             nil,
 		thresholdNotifiers:           []ThresholdNotifier{},
+		etcHostsPath:                 etcHostsPath,
 	}
 	return manager, manager
 }
@@ -514,7 +519,7 @@ func (m *managerImpl) podEphemeralStorageLimitEviction(podStats statsapi.PodStat
 	} else {
 		fsStatsSet = []fsStatsType{fsStatsRoot, fsStatsLogs, fsStatsLocalVolumeSource}
 	}
-	podEphemeralUsage, err := podLocalEphemeralStorageUsage(podStats, pod, fsStatsSet)
+	podEphemeralUsage, err := podLocalEphemeralStorageUsage(podStats, pod, fsStatsSet, m.etcHostsPath(pod.UID))
 	if err != nil {
 		klog.Errorf("eviction manager: error getting pod disk usage %v", err)
 		return false

pkg/kubelet/eviction/helpers.go

@@ -18,6 +18,7 @@ package eviction
 
 import (
 	"fmt"
+	"os"
 	"sort"
 	"strconv"
 	"strings"
@@ -424,7 +425,7 @@ func localEphemeralVolumeNames(pod *v1.Pod) []string {
 }
 
 // podLocalEphemeralStorageUsage aggregates pod local ephemeral storage usage and inode consumption for the specified stats to measure.
-func podLocalEphemeralStorageUsage(podStats statsapi.PodStats, pod *v1.Pod, statsToMeasure []fsStatsType) (v1.ResourceList, error) {
+func podLocalEphemeralStorageUsage(podStats statsapi.PodStats, pod *v1.Pod, statsToMeasure []fsStatsType, etcHostsPath string) (v1.ResourceList, error) {
 	disk := resource.Quantity{Format: resource.BinarySI}
 	inodes := resource.Quantity{Format: resource.DecimalSI}
 
@@ -438,6 +439,12 @@ func podLocalEphemeralStorageUsage(podStats statsapi.PodStats, pod *v1.Pod, stat
 		disk.Add(podLocalVolumeUsageList[v1.ResourceEphemeralStorage])
 		inodes.Add(podLocalVolumeUsageList[resourceInodes])
 	}
+	if len(etcHostsPath) > 0 {
+		if stat, err := os.Stat(etcHostsPath); err == nil {
+			disk.Add(*resource.NewQuantity(int64(stat.Size()), resource.BinarySI))
+			inodes.Add(*resource.NewQuantity(int64(1), resource.DecimalSI))
+		}
+	}
 	return v1.ResourceList{
 		v1.ResourceEphemeralStorage: disk,
 		resourceInodes:              inodes,

pkg/kubelet/kubelet.go

@@ -772,8 +772,9 @@ func NewMainKubelet(kubeCfg *kubeletconfiginternal.KubeletConfiguration,
 	klet.backOff = flowcontrol.NewBackOff(backOffPeriod, MaxContainerBackOff)
 	klet.podKillingCh = make(chan *kubecontainer.PodPair, podKillingChannelCapacity)
 
+	etcHostsPathFunc := func(podUID types.UID) string { return getEtcHostsPath(klet.getPodDir(podUID)) }
 	// setup eviction manager
-	evictionManager, evictionAdmitHandler := eviction.NewManager(klet.resourceAnalyzer, evictionConfig, killPodNow(klet.podWorkers, kubeDeps.Recorder), klet.podManager.GetMirrorPodByPod, klet.imageManager, klet.containerGC, kubeDeps.Recorder, nodeRef, klet.clock)
+	evictionManager, evictionAdmitHandler := eviction.NewManager(klet.resourceAnalyzer, evictionConfig, killPodNow(klet.podWorkers, kubeDeps.Recorder), klet.podManager.GetMirrorPodByPod, klet.imageManager, klet.containerGC, kubeDeps.Recorder, nodeRef, klet.clock, etcHostsPathFunc)
 
 	klet.evictionManager = evictionManager
 	klet.admitHandlers.AddPodAdmitHandler(evictionAdmitHandler)

pkg/kubelet/kubelet_pods.go

@@ -288,11 +288,16 @@ func translateMountPropagation(mountMode *v1.MountPropagationMode) (runtimeapi.M
 	}
 }
 
+// getEtcHostsPath returns the full host-side path to a pod's generated /etc/hosts file
+func getEtcHostsPath(podDir string) string {
+	return path.Join(podDir, "etc-hosts")
+}
+
 // makeHostsMount makes the mountpoint for the hosts file that the containers
 // in a pod are injected with. podIPs is provided instead of podIP as podIPs
 // are present even if dual-stack feature flag is not enabled.
 func makeHostsMount(podDir string, podIPs []string, hostName, hostDomainName string, hostAliases []v1.HostAlias, useHostNetwork bool) (*kubecontainer.Mount, error) {
-	hostsFilePath := path.Join(podDir, "etc-hosts")
+	hostsFilePath := getEtcHostsPath(podDir)
 	if err := ensureHostsFile(hostsFilePath, podIPs, hostName, hostDomainName, hostAliases, useHostNetwork); err != nil {
 		return nil, err
 	}

pkg/kubelet/kubelet_test.go

@@ -292,8 +292,9 @@ func newTestKubeletWithImageList(
 		UID:       types.UID(kubelet.nodeName),
 		Namespace: "",
 	}
+	etcHostsPathFunc := func(podUID types.UID) string { return getEtcHostsPath(kubelet.getPodDir(podUID)) }
 	// setup eviction manager
-	evictionManager, evictionAdmitHandler := eviction.NewManager(kubelet.resourceAnalyzer, eviction.Config{}, killPodNow(kubelet.podWorkers, fakeRecorder), kubelet.podManager.GetMirrorPodByPod, kubelet.imageManager, kubelet.containerGC, fakeRecorder, nodeRef, kubelet.clock)
+	evictionManager, evictionAdmitHandler := eviction.NewManager(kubelet.resourceAnalyzer, eviction.Config{}, killPodNow(kubelet.podWorkers, fakeRecorder), kubelet.podManager.GetMirrorPodByPod, kubelet.imageManager, kubelet.containerGC, fakeRecorder, nodeRef, kubelet.clock, etcHostsPathFunc)
 
 	kubelet.evictionManager = evictionManager
 	kubelet.admitHandlers.AddPodAdmitHandler(evictionAdmitHandler)

pkg/kubelet/runonce_test.go

@@ -126,7 +126,8 @@ func TestRunOnce(t *testing.T) {
 		return nil
 	}
 	fakeMirrodPodFunc := func(*v1.Pod) (*v1.Pod, bool) { return nil, false }
-	evictionManager, evictionAdmitHandler := eviction.NewManager(kb.resourceAnalyzer, eviction.Config{}, fakeKillPodFunc, fakeMirrodPodFunc, nil, nil, kb.recorder, nodeRef, kb.clock)
+	etcHostsPathFunc := func(podUID types.UID) string { return getEtcHostsPath(kb.getPodDir(podUID)) }
+	evictionManager, evictionAdmitHandler := eviction.NewManager(kb.resourceAnalyzer, eviction.Config{}, fakeKillPodFunc, fakeMirrodPodFunc, nil, nil, kb.recorder, nodeRef, kb.clock, etcHostsPathFunc)
 
 	kb.evictionManager = evictionManager
 	kb.admitHandlers.AddPodAdmitHandler(evictionAdmitHandler)