Add glide.yaml and vendor deps

vendor/k8s.io/kubernetes/pkg/kubelet/eviction/eviction_manager.go

@@ -0,0 +1,363 @@
+/*
+Copyright 2016 The Kubernetes Authors.
+
+Licensed under the Apache License, Version 2.0 (the "License");
+you may not use this file except in compliance with the License.
+You may obtain a copy of the License at
+
+    http://www.apache.org/licenses/LICENSE-2.0
+
+Unless required by applicable law or agreed to in writing, software
+distributed under the License is distributed on an "AS IS" BASIS,
+WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+See the License for the specific language governing permissions and
+limitations under the License.
+*/
+
+package eviction
+
+import (
+	"fmt"
+	"sort"
+	"sync"
+	"time"
+
+	"github.com/golang/glog"
+	"k8s.io/kubernetes/pkg/api/resource"
+	"k8s.io/kubernetes/pkg/api/v1"
+	"k8s.io/kubernetes/pkg/client/record"
+	"k8s.io/kubernetes/pkg/kubelet/cm"
+	"k8s.io/kubernetes/pkg/kubelet/lifecycle"
+	"k8s.io/kubernetes/pkg/kubelet/qos"
+	"k8s.io/kubernetes/pkg/kubelet/server/stats"
+	"k8s.io/kubernetes/pkg/kubelet/util/format"
+	"k8s.io/kubernetes/pkg/util/clock"
+	"k8s.io/kubernetes/pkg/util/wait"
+)
+
+// managerImpl implements Manager
+type managerImpl struct {
+	//  used to track time
+	clock clock.Clock
+	// config is how the manager is configured
+	config Config
+	// the function to invoke to kill a pod
+	killPodFunc KillPodFunc
+	// the interface that knows how to do image gc
+	imageGC ImageGC
+	// protects access to internal state
+	sync.RWMutex
+	// node conditions are the set of conditions present
+	nodeConditions []v1.NodeConditionType
+	// captures when a node condition was last observed based on a threshold being met
+	nodeConditionsLastObservedAt nodeConditionsObservedAt
+	// nodeRef is a reference to the node
+	nodeRef *v1.ObjectReference
+	// used to record events about the node
+	recorder record.EventRecorder
+	// used to measure usage stats on system
+	summaryProvider stats.SummaryProvider
+	// records when a threshold was first observed
+	thresholdsFirstObservedAt thresholdsObservedAt
+	// records the set of thresholds that have been met (including graceperiod) but not yet resolved
+	thresholdsMet []Threshold
+	// resourceToRankFunc maps a resource to ranking function for that resource.
+	resourceToRankFunc map[v1.ResourceName]rankFunc
+	// resourceToNodeReclaimFuncs maps a resource to an ordered list of functions that know how to reclaim that resource.
+	resourceToNodeReclaimFuncs map[v1.ResourceName]nodeReclaimFuncs
+	// last observations from synchronize
+	lastObservations signalObservations
+	// notifiersInitialized indicates if the threshold notifiers have been initialized (i.e. synchronize() has been called once)
+	notifiersInitialized bool
+}
+
+// ensure it implements the required interface
+var _ Manager = &managerImpl{}
+
+// NewManager returns a configured Manager and an associated admission handler to enforce eviction configuration.
+func NewManager(
+	summaryProvider stats.SummaryProvider,
+	config Config,
+	killPodFunc KillPodFunc,
+	imageGC ImageGC,
+	recorder record.EventRecorder,
+	nodeRef *v1.ObjectReference,
+	clock clock.Clock) (Manager, lifecycle.PodAdmitHandler, error) {
+	manager := &managerImpl{
+		clock:           clock,
+		killPodFunc:     killPodFunc,
+		imageGC:         imageGC,
+		config:          config,
+		recorder:        recorder,
+		summaryProvider: summaryProvider,
+		nodeRef:         nodeRef,
+		nodeConditionsLastObservedAt: nodeConditionsObservedAt{},
+		thresholdsFirstObservedAt:    thresholdsObservedAt{},
+	}
+	return manager, manager, nil
+}
+
+// Admit rejects a pod if its not safe to admit for node stability.
+func (m *managerImpl) Admit(attrs *lifecycle.PodAdmitAttributes) lifecycle.PodAdmitResult {
+	m.RLock()
+	defer m.RUnlock()
+	if len(m.nodeConditions) == 0 {
+		return lifecycle.PodAdmitResult{Admit: true}
+	}
+
+	// the node has memory pressure, admit if not best-effort
+	if hasNodeCondition(m.nodeConditions, v1.NodeMemoryPressure) {
+		notBestEffort := qos.BestEffort != qos.GetPodQOS(attrs.Pod)
+		if notBestEffort {
+			return lifecycle.PodAdmitResult{Admit: true}
+		}
+	}
+
+	// reject pods when under memory pressure (if pod is best effort), or if under disk pressure.
+	glog.Warningf("Failed to admit pod %v - %s", format.Pod(attrs.Pod), "node has conditions: %v", m.nodeConditions)
+	return lifecycle.PodAdmitResult{
+		Admit:   false,
+		Reason:  reason,
+		Message: fmt.Sprintf(message, m.nodeConditions),
+	}
+}
+
+// Start starts the control loop to observe and response to low compute resources.
+func (m *managerImpl) Start(diskInfoProvider DiskInfoProvider, podFunc ActivePodsFunc, monitoringInterval time.Duration) error {
+	// start the eviction manager monitoring
+	go wait.Until(func() { m.synchronize(diskInfoProvider, podFunc) }, monitoringInterval, wait.NeverStop)
+	return nil
+}
+
+// IsUnderMemoryPressure returns true if the node is under memory pressure.
+func (m *managerImpl) IsUnderMemoryPressure() bool {
+	m.RLock()
+	defer m.RUnlock()
+	return hasNodeCondition(m.nodeConditions, v1.NodeMemoryPressure)
+}
+
+// IsUnderDiskPressure returns true if the node is under disk pressure.
+func (m *managerImpl) IsUnderDiskPressure() bool {
+	m.RLock()
+	defer m.RUnlock()
+	return hasNodeCondition(m.nodeConditions, v1.NodeDiskPressure)
+}
+
+func startMemoryThresholdNotifier(thresholds []Threshold, observations signalObservations, hard bool, handler thresholdNotifierHandlerFunc) error {
+	for _, threshold := range thresholds {
+		if threshold.Signal != SignalMemoryAvailable || hard != isHardEvictionThreshold(threshold) {
+			continue
+		}
+		observed, found := observations[SignalMemoryAvailable]
+		if !found {
+			continue
+		}
+		cgroups, err := cm.GetCgroupSubsystems()
+		if err != nil {
+			return err
+		}
+		// TODO add support for eviction from --cgroup-root
+		cgpath, found := cgroups.MountPoints["memory"]
+		if !found || len(cgpath) == 0 {
+			return fmt.Errorf("memory cgroup mount point not found")
+		}
+		attribute := "memory.usage_in_bytes"
+		quantity := getThresholdQuantity(threshold.Value, observed.capacity)
+		usageThreshold := resource.NewQuantity(observed.capacity.Value(), resource.DecimalSI)
+		usageThreshold.Sub(*quantity)
+		description := fmt.Sprintf("<%s available", formatThresholdValue(threshold.Value))
+		memcgThresholdNotifier, err := NewMemCGThresholdNotifier(cgpath, attribute, usageThreshold.String(), description, handler)
+		if err != nil {
+			return err
+		}
+		go memcgThresholdNotifier.Start(wait.NeverStop)
+		return nil
+	}
+	return nil
+}
+
+// synchronize is the main control loop that enforces eviction thresholds.
+func (m *managerImpl) synchronize(diskInfoProvider DiskInfoProvider, podFunc ActivePodsFunc) {
+	// if we have nothing to do, just return
+	thresholds := m.config.Thresholds
+	if len(thresholds) == 0 {
+		return
+	}
+
+	// build the ranking functions (if not yet known)
+	// TODO: have a function in cadvisor that lets us know if global housekeeping has completed
+	if len(m.resourceToRankFunc) == 0 || len(m.resourceToNodeReclaimFuncs) == 0 {
+		// this may error if cadvisor has yet to complete housekeeping, so we will just try again in next pass.
+		hasDedicatedImageFs, err := diskInfoProvider.HasDedicatedImageFs()
+		if err != nil {
+			return
+		}
+		m.resourceToRankFunc = buildResourceToRankFunc(hasDedicatedImageFs)
+		m.resourceToNodeReclaimFuncs = buildResourceToNodeReclaimFuncs(m.imageGC, hasDedicatedImageFs)
+	}
+
+	// make observations and get a function to derive pod usage stats relative to those observations.
+	observations, statsFunc, err := makeSignalObservations(m.summaryProvider)
+	if err != nil {
+		glog.Errorf("eviction manager: unexpected err: %v", err)
+		return
+	}
+
+	// attempt to create a threshold notifier to improve eviction response time
+	if !m.notifiersInitialized {
+		m.notifiersInitialized = true
+		// start soft memory notification
+		err = startMemoryThresholdNotifier(m.config.Thresholds, observations, false, func(desc string) {
+			glog.Infof("soft memory eviction threshold crossed at %s", desc)
+			// TODO wait grace period for soft memory limit
+			m.synchronize(diskInfoProvider, podFunc)
+		})
+		if err != nil {
+			glog.Warningf("eviction manager: failed to create hard memory threshold notifier: %v", err)
+		}
+		// start hard memory notification
+		err = startMemoryThresholdNotifier(m.config.Thresholds, observations, true, func(desc string) {
+			glog.Infof("hard memory eviction threshold crossed at %s", desc)
+			m.synchronize(diskInfoProvider, podFunc)
+		})
+		if err != nil {
+			glog.Warningf("eviction manager: failed to create soft memory threshold notifier: %v", err)
+		}
+	}
+
+	// determine the set of thresholds met independent of grace period
+	thresholds = thresholdsMet(thresholds, observations, false)
+
+	// determine the set of thresholds previously met that have not yet satisfied the associated min-reclaim
+	if len(m.thresholdsMet) > 0 {
+		thresholdsNotYetResolved := thresholdsMet(m.thresholdsMet, observations, true)
+		thresholds = mergeThresholds(thresholds, thresholdsNotYetResolved)
+	}
+
+	// determine the set of thresholds whose stats have been updated since the last sync
+	thresholds = thresholdsUpdatedStats(thresholds, observations, m.lastObservations)
+
+	// track when a threshold was first observed
+	now := m.clock.Now()
+	thresholdsFirstObservedAt := thresholdsFirstObservedAt(thresholds, m.thresholdsFirstObservedAt, now)
+
+	// the set of node conditions that are triggered by currently observed thresholds
+	nodeConditions := nodeConditions(thresholds)
+
+	// track when a node condition was last observed
+	nodeConditionsLastObservedAt := nodeConditionsLastObservedAt(nodeConditions, m.nodeConditionsLastObservedAt, now)
+
+	// node conditions report true if it has been observed within the transition period window
+	nodeConditions = nodeConditionsObservedSince(nodeConditionsLastObservedAt, m.config.PressureTransitionPeriod, now)
+
+	// determine the set of thresholds we need to drive eviction behavior (i.e. all grace periods are met)
+	thresholds = thresholdsMetGracePeriod(thresholdsFirstObservedAt, now)
+
+	// update internal state
+	m.Lock()
+	m.nodeConditions = nodeConditions
+	m.thresholdsFirstObservedAt = thresholdsFirstObservedAt
+	m.nodeConditionsLastObservedAt = nodeConditionsLastObservedAt
+	m.thresholdsMet = thresholds
+	m.lastObservations = observations
+	m.Unlock()
+
+	// determine the set of resources under starvation
+	starvedResources := getStarvedResources(thresholds)
+	if len(starvedResources) == 0 {
+		glog.V(3).Infof("eviction manager: no resources are starved")
+		return
+	}
+
+	// rank the resources to reclaim by eviction priority
+	sort.Sort(byEvictionPriority(starvedResources))
+	resourceToReclaim := starvedResources[0]
+	glog.Warningf("eviction manager: attempting to reclaim %v", resourceToReclaim)
+
+	// determine if this is a soft or hard eviction associated with the resource
+	softEviction := isSoftEvictionThresholds(thresholds, resourceToReclaim)
+
+	// record an event about the resources we are now attempting to reclaim via eviction
+	m.recorder.Eventf(m.nodeRef, v1.EventTypeWarning, "EvictionThresholdMet", "Attempting to reclaim %s", resourceToReclaim)
+
+	// check if there are node-level resources we can reclaim to reduce pressure before evicting end-user pods.
+	if m.reclaimNodeLevelResources(resourceToReclaim, observations) {
+		glog.Infof("eviction manager: able to reduce %v pressure without evicting pods.", resourceToReclaim)
+		return
+	}
+
+	glog.Infof("eviction manager: must evict pod(s) to reclaim %v", resourceToReclaim)
+
+	// rank the pods for eviction
+	rank, ok := m.resourceToRankFunc[resourceToReclaim]
+	if !ok {
+		glog.Errorf("eviction manager: no ranking function for resource %s", resourceToReclaim)
+		return
+	}
+
+	// the only candidates viable for eviction are those pods that had anything running.
+	activePods := podFunc()
+	if len(activePods) == 0 {
+		glog.Errorf("eviction manager: eviction thresholds have been met, but no pods are active to evict")
+		return
+	}
+
+	// rank the running pods for eviction for the specified resource
+	rank(activePods, statsFunc)
+
+	glog.Infof("eviction manager: pods ranked for eviction: %s", format.Pods(activePods))
+
+	// we kill at most a single pod during each eviction interval
+	for i := range activePods {
+		pod := activePods[i]
+		status := v1.PodStatus{
+			Phase:   v1.PodFailed,
+			Message: fmt.Sprintf(message, resourceToReclaim),
+			Reason:  reason,
+		}
+		// record that we are evicting the pod
+		m.recorder.Eventf(pod, v1.EventTypeWarning, reason, fmt.Sprintf(message, resourceToReclaim))
+		gracePeriodOverride := int64(0)
+		if softEviction {
+			gracePeriodOverride = m.config.MaxPodGracePeriodSeconds
+		}
+		// this is a blocking call and should only return when the pod and its containers are killed.
+		err := m.killPodFunc(pod, status, &gracePeriodOverride)
+		if err != nil {
+			glog.Infof("eviction manager: pod %s failed to evict %v", format.Pod(pod), err)
+			continue
+		}
+		// success, so we return until the next housekeeping interval
+		glog.Infof("eviction manager: pod %s evicted successfully", format.Pod(pod))
+		return
+	}
+	glog.Infof("eviction manager: unable to evict any pods from the node")
+}
+
+// reclaimNodeLevelResources attempts to reclaim node level resources.  returns true if thresholds were satisfied and no pod eviction is required.
+func (m *managerImpl) reclaimNodeLevelResources(resourceToReclaim v1.ResourceName, observations signalObservations) bool {
+	nodeReclaimFuncs := m.resourceToNodeReclaimFuncs[resourceToReclaim]
+	for _, nodeReclaimFunc := range nodeReclaimFuncs {
+		// attempt to reclaim the pressured resource.
+		reclaimed, err := nodeReclaimFunc()
+		if err == nil {
+			// update our local observations based on the amount reported to have been reclaimed.
+			// note: this is optimistic, other things could have been still consuming the pressured resource in the interim.
+			signal := resourceToSignal[resourceToReclaim]
+			value, ok := observations[signal]
+			if !ok {
+				glog.Errorf("eviction manager: unable to find value associated with signal %v", signal)
+				continue
+			}
+			value.available.Add(*reclaimed)
+
+			// evaluate all current thresholds to see if with adjusted observations, we think we have met min reclaim goals
+			if len(thresholdsMet(m.thresholdsMet, observations, true)) == 0 {
+				return true
+			}
+		} else {
+			glog.Errorf("eviction manager: unexpected error when attempting to reduce %v pressure: %v", resourceToReclaim, err)
+		}
+	}
+	return false
+}