func NewFarm(
	kpStore kp.Store,
	rcs rcstore.Store,
	scheduler scheduler.Scheduler,
	labeler labels.Applicator,
	sessions <-chan string,
	logger logging.Logger,
	rcSelector klabels.Selector,
	alerter alerting.Alerter,
) *Farm {
	if alerter == nil {
		alerter = alerting.NewNop()
	}

	return &Farm{
		kpStore:    kpStore,
		rcStore:    rcs,
		scheduler:  scheduler,
		labeler:    labeler,
		sessions:   sessions,
		logger:     logger,
		children:   make(map[fields.ID]childRC),
		alerter:    alerter,
		rcSelector: rcSelector,
		metrics:    rcmetrics.NewMetrics(logger),
	}
}

func (f UpdateFactory) New(u roll_fields.Update, l logging.Logger, session kp.Session, alerter alerting.Alerter) Update {
	if alerter == nil {
		alerter = alerting.NewNop()
	}

	return NewUpdate(u, f.KPStore, f.RCStore, f.HealthChecker, f.Labeler, f.Scheduler, l, session, alerter)
}

func NewFarm(
	factory Factory,
	kps kp.Store,
	rls rollstore.Store,
	rcs RCGetter,
	sessions <-chan string,
	logger logging.Logger,
	labeler rc.Labeler,
	rcSelector klabels.Selector,
	alerter alerting.Alerter,
) *Farm {
	if alerter == nil {
		alerter = alerting.NewNop()
	}
	return &Farm{
		factory:    factory,
		kps:        kps,
		rls:        rls,
		rcs:        rcs,
		sessions:   sessions,
		logger:     logger,
		children:   make(map[roll_fields.ID]childRU),
		labeler:    labeler,
		rcSelector: rcSelector,
		alerter:    alerter,
	}
}

func NewFarm(
	store store,
	rcs rcstore.Store,
	scheduler scheduler.Scheduler,
	labeler Labeler,
	sessions <-chan string,
	logger logging.Logger,
	rcSelector klabels.Selector,
	alerter alerting.Alerter,
	rcWatchPauseTime time.Duration,
) *Farm {
	if alerter == nil {
		alerter = alerting.NewNop()
	}

	return &Farm{
		store:            store,
		rcStore:          rcs,
		scheduler:        scheduler,
		labeler:          labeler,
		sessions:         sessions,
		logger:           logger,
		children:         make(map[fields.ID]childRC),
		alerter:          alerter,
		rcSelector:       rcSelector,
		rcWatchPauseTime: rcWatchPauseTime,
	}
}

// Create a new Update. The kp.Store, rcstore.Store, labels.Applicator and
// scheduler.Scheduler arguments should be the same as those of the RCs themselves. The
// session must be valid for the lifetime of the Update; maintaining this is the
// responsibility of the caller.
func NewUpdate(
	f fields.Update,
	kps kp.Store,
	rcs rcstore.Store,
	hcheck checker.ConsulHealthChecker,
	labeler rc.Labeler,
	sched scheduler.Scheduler,
	logger logging.Logger,
	session kp.Session,
	alerter alerting.Alerter,
) Update {
	if alerter == nil {
		alerter = alerting.NewNop()
	}

	logger = logger.SubLogger(logrus.Fields{
		"desired_replicas": f.DesiredReplicas,
		"minimum_replicas": f.MinimumReplicas,
	})
	return &update{
		Update:  f,
		kps:     kps,
		rcs:     rcs,
		hcheck:  hcheck,
		labeler: labeler,
		sched:   sched,
		logger:  logger,
		session: session,
		alerter: alerter,
	}
}

func New(
	fields fields.RC,
	kpStore kpStore,
	rcStore rcstore.Store,
	scheduler scheduler.Scheduler,
	podApplicator labels.Applicator,
	logger logging.Logger,
	alerter alerting.Alerter,
) ReplicationController {
	if alerter == nil {
		alerter = alerting.NewNop()
	}

	return &replicationController{
		RC: fields,

		logger:        logger,
		kpStore:       kpStore,
		rcStore:       rcStore,
		scheduler:     scheduler,
		podApplicator: podApplicator,
		alerter:       alerter,
	}
}

func TestMultipleFarms(t *testing.T) {
	retryInterval = testFarmRetryInterval

	dsStore := dsstoretest.NewFake()
	kpStore := kptest.NewFakePodStore(make(map[kptest.FakePodStoreKey]manifest.Manifest), make(map[string]kp.WatchResult))
	applicator := labels.NewFakeApplicator()

	preparer := kptest.NewFakePreparer(kpStore, logging.DefaultLogger)
	preparer.Enable()
	defer preparer.Disable()

	session := kptest.NewSession()
	firstLogger := logging.DefaultLogger.SubLogger(logrus.Fields{
		"farm": "firstMultiple",
	})

	var allNodes []types.NodeName
	allNodes = append(allNodes, "node1", "node2", "node3")
	for i := 0; i < 10; i++ {
		nodeName := fmt.Sprintf("good_node%v", i)
		allNodes = append(allNodes, types.NodeName(nodeName))
	}
	happyHealthChecker := fake_checker.HappyHealthChecker(allNodes)

	//
	// Instantiate first farm
	//
	firstFarm := &Farm{
		dsStore:       dsStore,
		kpStore:       kpStore,
		scheduler:     scheduler.NewApplicatorScheduler(applicator),
		applicator:    applicator,
		children:      make(map[ds_fields.ID]*childDS),
		session:       session,
		logger:        firstLogger,
		alerter:       alerting.NewNop(),
		healthChecker: &happyHealthChecker,
	}
	firstQuitCh := make(chan struct{})
	defer close(firstQuitCh)
	go func() {
		go firstFarm.cleanupDaemonSetPods(firstQuitCh)
		firstFarm.mainLoop(firstQuitCh)
	}()

	//
	// Instantiate second farm
	//
	secondLogger := logging.DefaultLogger.SubLogger(logrus.Fields{
		"farm": "secondMultiple",
	})
	secondFarm := &Farm{
		dsStore:       dsStore,
		kpStore:       kpStore,
		scheduler:     scheduler.NewApplicatorScheduler(applicator),
		applicator:    applicator,
		children:      make(map[ds_fields.ID]*childDS),
		session:       session,
		logger:        secondLogger,
		alerter:       alerting.NewNop(),
		healthChecker: &happyHealthChecker,
	}
	secondQuitCh := make(chan struct{})
	defer close(secondQuitCh)
	go func() {
		go secondFarm.cleanupDaemonSetPods(secondQuitCh)
		secondFarm.mainLoop(secondQuitCh)
	}()

	// Make two daemon sets with difference node selectors
	// First daemon set
	podID := types.PodID("testPod")
	minHealth := 0
	clusterName := ds_fields.ClusterName("some_name")

	manifestBuilder := manifest.NewBuilder()
	manifestBuilder.SetID(podID)
	podManifest := manifestBuilder.GetManifest()

	nodeSelector := klabels.Everything().Add(pc_fields.AvailabilityZoneLabel, klabels.EqualsOperator, []string{"az1"})
	dsData, err := dsStore.Create(podManifest, minHealth, clusterName, nodeSelector, podID, replicationTimeout)
	Assert(t).IsNil(err, "Expected no error creating request")

	// Second daemon set
	anotherNodeSelector := klabels.Everything().Add(pc_fields.AvailabilityZoneLabel, klabels.EqualsOperator, []string{"az2"})
	anotherDSData, err := dsStore.Create(podManifest, minHealth, clusterName, anotherNodeSelector, podID, replicationTimeout)
	Assert(t).IsNil(err, "Expected no error creating request")

	// Make a node and verify that it was scheduled by the first daemon set
	applicator.SetLabel(labels.NODE, "node1", pc_fields.AvailabilityZoneLabel, "az1")

	labeled, err := waitForPodLabel(applicator, true, "node1/testPod")
	Assert(t).IsNil(err, "Expected pod to have a dsID label")
	dsID := labeled.Labels.Get(DSIDLabel)
	Assert(t).AreEqual(dsData.ID.String(), dsID, "Unexpected dsID labeled")

	// Make a second node and verify that it was scheduled by the second daemon set
	applicator.SetLabel(labels.NODE, "node2", pc_fields.AvailabilityZoneLabel, "az2")

	labeled, err = waitForPodLabel(applicator, true, "node2/testPod")
//.........这里部分代码省略.........

func TestCleanupPods(t *testing.T) {
	retryInterval = testFarmRetryInterval

	dsStore := dsstoretest.NewFake()
	kpStore := kptest.NewFakePodStore(make(map[kptest.FakePodStoreKey]manifest.Manifest), make(map[string]kp.WatchResult))
	applicator := labels.NewFakeApplicator()

	preparer := kptest.NewFakePreparer(kpStore, logging.DefaultLogger)
	preparer.Enable()
	defer preparer.Disable()

	// Make some dangling pod labels and instantiate a farm and expect it clean it up
	podID := types.PodID("testPod")
	manifestBuilder := manifest.NewBuilder()
	manifestBuilder.SetID(podID)
	podManifest := manifestBuilder.GetManifest()

	var allNodes []types.NodeName
	allNodes = append(allNodes)
	for i := 0; i < 10; i++ {
		nodeName := fmt.Sprintf("node%v", i)
		allNodes = append(allNodes, types.NodeName(nodeName))
	}
	happyHealthChecker := fake_checker.HappyHealthChecker(allNodes)

	for i := 0; i < 10; i++ {
		nodeName := fmt.Sprintf("node%v", i)
		id := labels.MakePodLabelKey(types.NodeName(nodeName), podID)
		err := applicator.SetLabel(labels.POD, id, DSIDLabel, "impossible_id")
		Assert(t).IsNil(err, "Expected no error labeling node")

		_, err = kpStore.SetPod(kp.INTENT_TREE, types.NodeName(nodeName), podManifest)
		Assert(t).IsNil(err, "Expected no error added pod to intent tree")
	}

	// Assert that precondition is true
	for i := 0; i < 10; i++ {
		nodeName := fmt.Sprintf("node%v", i)
		id := labels.MakePodLabelKey(types.NodeName(nodeName), podID)
		labeled, err := applicator.GetLabels(labels.POD, id)
		Assert(t).IsNil(err, "Expected no error getting labels")
		Assert(t).IsTrue(labeled.Labels.Has(DSIDLabel), "Precondition failed: Pod must have a dsID label")

		_, _, err = kpStore.Pod(kp.INTENT_TREE, types.NodeName(nodeName), podID)
		Assert(t).IsNil(err, "Expected no error getting pod from intent store")
		Assert(t).AreNotEqual(err, pods.NoCurrentManifest, "Precondition failed: Pod was not in intent store")
	}

	// Instantiate farm
	logger := logging.DefaultLogger.SubLogger(logrus.Fields{
		"farm": "cleanupPods",
	})
	dsf := &Farm{
		dsStore:       dsStore,
		kpStore:       kpStore,
		scheduler:     scheduler.NewApplicatorScheduler(applicator),
		applicator:    applicator,
		children:      make(map[ds_fields.ID]*childDS),
		session:       kptest.NewSession(),
		logger:        logger,
		alerter:       alerting.NewNop(),
		healthChecker: &happyHealthChecker,
	}
	quitCh := make(chan struct{})
	defer close(quitCh)
	go func() {
		go dsf.cleanupDaemonSetPods(quitCh)
		dsf.mainLoop(quitCh)
	}()

	// Make there are no nodes left
	for i := 0; i < 10; i++ {
		nodeName := fmt.Sprintf("node%v", i)
		id := labels.MakePodLabelKey(types.NodeName(nodeName), podID)
		_, err := waitForPodLabel(applicator, false, id)
		Assert(t).IsNil(err, "Expected pod not to have a dsID label")

		condition := func() error {
			_, _, err = kpStore.Pod(kp.INTENT_TREE, types.NodeName(nodeName), podID)
			if err != pods.NoCurrentManifest {
				return util.Errorf("Expected pod to be deleted in intent store")
			}
			return nil
		}
		err = waitForCondition(condition)
		Assert(t).IsNil(err, "Error cleaning up pods")
	}
}

// Tests dsContends for changes to both daemon sets and nodes
func TestContendNodes(t *testing.T) {
	retryInterval = testFarmRetryInterval

	//
	// Instantiate farm
	//
	dsStore := dsstoretest.NewFake()
	kpStore := kptest.NewFakePodStore(make(map[kptest.FakePodStoreKey]manifest.Manifest), make(map[string]kp.WatchResult))
	applicator := labels.NewFakeApplicator()
	logger := logging.DefaultLogger.SubLogger(logrus.Fields{
		"farm": "contendNodes",
	})
	preparer := kptest.NewFakePreparer(kpStore, logging.DefaultLogger)
	preparer.Enable()
	defer preparer.Disable()

	var allNodes []types.NodeName
	allNodes = append(allNodes, "node1")
	happyHealthChecker := fake_checker.HappyHealthChecker(allNodes)

	dsf := &Farm{
		dsStore:       dsStore,
		kpStore:       kpStore,
		scheduler:     scheduler.NewApplicatorScheduler(applicator),
		applicator:    applicator,
		children:      make(map[ds_fields.ID]*childDS),
		session:       kptest.NewSession(),
		logger:        logger,
		alerter:       alerting.NewNop(),
		healthChecker: &happyHealthChecker,
	}
	quitCh := make(chan struct{})
	defer close(quitCh)
	go func() {
		go dsf.cleanupDaemonSetPods(quitCh)
		dsf.mainLoop(quitCh)
	}()

	//
	// Check for contention between two daemon sets among their nodes
	//
	// Make a daemon set
	podID := types.PodID("testPod")
	minHealth := 0
	clusterName := ds_fields.ClusterName("some_name")

	manifestBuilder := manifest.NewBuilder()
	manifestBuilder.SetID(podID)
	podManifest := manifestBuilder.GetManifest()

	nodeSelector := klabels.Everything().Add(pc_fields.AvailabilityZoneLabel, klabels.EqualsOperator, []string{"az1"})
	dsData, err := dsStore.Create(podManifest, minHealth, clusterName, nodeSelector, podID, replicationTimeout)
	Assert(t).IsNil(err, "Expected no error creating request")
	err = waitForCreate(dsf, dsData.ID)
	Assert(t).IsNil(err, "Expected daemon set to be created")

	// Make a node and verify that it was scheduled
	applicator.SetLabel(labels.NODE, "node1", pc_fields.AvailabilityZoneLabel, "az1")

	labeled, err := waitForPodLabel(applicator, true, "node1/testPod")
	Assert(t).IsNil(err, "Expected pod to have a dsID label")
	dsID := labeled.Labels.Get(DSIDLabel)
	Assert(t).AreEqual(dsData.ID.String(), dsID, "Unexpected dsID labeled")

	// Make another daemon set with a contending AvailabilityZoneLabel and verify
	// that it gets disabled and that the node label does not change
	anotherDSData, err := dsStore.Create(podManifest, minHealth, clusterName, nodeSelector, podID, replicationTimeout)
	Assert(t).AreNotEqual(dsData.ID.String(), anotherDSData.ID.String(), "Precondition failed")
	Assert(t).IsNil(err, "Expected no error creating request")
	err = waitForCreate(dsf, anotherDSData.ID)
	Assert(t).IsNil(err, "Expected daemon set to be created")

	labeled, err = waitForPodLabel(applicator, true, "node1/testPod")
	Assert(t).IsNil(err, "Expected pod to have a dsID label")
	anotherDSID := labeled.Labels.Get(DSIDLabel)
	Assert(t).AreEqual(dsData.ID.String(), anotherDSID, "Expected pod label not to be overwritten")

	// Expect the new daemon set to be disabled both in the farm and in the dsStore
	err = waitForDisabled(dsf, dsStore, anotherDSData.ID, true)
	Assert(t).IsNil(err, "Error disabling daemon set!")

	//
	// Make a third daemon set and update its node selector to force a contend,
	// then verify that it has been disabled and the node hasn't been overwritten
	//
	anotherSelector := klabels.Everything().Add(pc_fields.AvailabilityZoneLabel, klabels.EqualsOperator, []string{"undefined"})
	badDS, err := dsStore.Create(podManifest, minHealth, clusterName, anotherSelector, podID, replicationTimeout)
	Assert(t).IsNil(err, "Expected no error creating request")
	err = waitForCreate(dsf, badDS.ID)
	Assert(t).IsNil(err, "Expected daemon set to be created")

	mutator := func(dsToUpdate ds_fields.DaemonSet) (ds_fields.DaemonSet, error) {
		dsToUpdate.NodeSelector = nodeSelector
		return dsToUpdate, nil
	}

	badDS, err = dsStore.MutateDS(badDS.ID, mutator)
	Assert(t).IsNil(err, "Expected no error mutating daemon set")
	err = waitForMutateSelector(dsf, badDS)
//.........这里部分代码省略.........

// Tests dsContends for NodeSelectors
func TestContendSelectors(t *testing.T) {
	retryInterval = testFarmRetryInterval

	//
	// Instantiate farm
	//
	dsStore := dsstoretest.NewFake()
	kpStore := kptest.NewFakePodStore(make(map[kptest.FakePodStoreKey]manifest.Manifest), make(map[string]kp.WatchResult))
	applicator := labels.NewFakeApplicator()
	logger := logging.DefaultLogger.SubLogger(logrus.Fields{
		"farm": "contendSelectors",
	})
	preparer := kptest.NewFakePreparer(kpStore, logging.DefaultLogger)
	preparer.Enable()
	defer preparer.Disable()

	var allNodes []types.NodeName
	happyHealthChecker := fake_checker.HappyHealthChecker(allNodes)

	dsf := &Farm{
		dsStore:       dsStore,
		kpStore:       kpStore,
		scheduler:     scheduler.NewApplicatorScheduler(applicator),
		applicator:    applicator,
		children:      make(map[ds_fields.ID]*childDS),
		session:       kptest.NewSession(),
		logger:        logger,
		alerter:       alerting.NewNop(),
		healthChecker: &happyHealthChecker,
	}
	quitCh := make(chan struct{})
	defer close(quitCh)
	go func() {
		go dsf.cleanupDaemonSetPods(quitCh)
		dsf.mainLoop(quitCh)
	}()

	//
	// Make two daemon sets with a everything selector and verify that they trivially
	// contend and that only the second daemon set gets disabled
	//
	// Make a daemon set
	podID := types.PodID("testPod")
	minHealth := 0
	clusterName := ds_fields.ClusterName("some_name")

	manifestBuilder := manifest.NewBuilder()
	manifestBuilder.SetID(podID)
	podManifest := manifestBuilder.GetManifest()

	everythingSelector := klabels.Everything()
	firstDSData, err := dsStore.Create(podManifest, minHealth, clusterName, everythingSelector, podID, replicationTimeout)
	Assert(t).IsNil(err, "Expected no error creating request")
	err = waitForCreate(dsf, firstDSData.ID)
	Assert(t).IsNil(err, "Expected daemon set to be created")

	secondDSData, err := dsStore.Create(podManifest, minHealth, clusterName, everythingSelector, podID, replicationTimeout)
	Assert(t).IsNil(err, "Expected no error creating request")
	err = waitForCreate(dsf, secondDSData.ID)
	Assert(t).IsNil(err, "Expected daemon set to be created")

	// Verify that only the second daemon set is disabled
	err = waitForDisabled(dsf, dsStore, firstDSData.ID, false)
	Assert(t).IsNil(err, "First daemon set should not be disabled")

	err = waitForDisabled(dsf, dsStore, secondDSData.ID, true)
	Assert(t).IsNil(err, "Error disabling second daemon set")

	// Add another daemon set with different selector and verify it gets disabled
	someSelector := klabels.Everything().
		Add(pc_fields.AvailabilityZoneLabel, klabels.EqualsOperator, []string{"nowhere"})
	thirdDSData, err := dsStore.Create(podManifest, minHealth, clusterName, someSelector, podID, replicationTimeout)
	Assert(t).IsNil(err, "Expected no error creating request")
	err = waitForCreate(dsf, thirdDSData.ID)
	Assert(t).IsNil(err, "Expected daemon set to be created")

	err = waitForDisabled(dsf, dsStore, thirdDSData.ID, true)
	Assert(t).IsNil(err, "Error disabling third daemon set")

	//
	// Disable first daemon set, then enable second and third daemon sets in that order
	// and then there should be a contend on the third daemon set
	//
	disableMutator := func(dsToUpdate ds_fields.DaemonSet) (ds_fields.DaemonSet, error) {
		dsToUpdate.Disabled = true
		return dsToUpdate, nil
	}

	enableMutator := func(dsToUpdate ds_fields.DaemonSet) (ds_fields.DaemonSet, error) {
		dsToUpdate.Disabled = false
		return dsToUpdate, nil
	}

	// Disable first ds and verify it is disabled
	_, err = dsStore.MutateDS(firstDSData.ID, disableMutator)
	Assert(t).IsNil(err, "Expected no error getting daemon set")

	err = waitForDisabled(dsf, dsStore, firstDSData.ID, true)
	Assert(t).IsNil(err, "Error disabling first daemon set")
//.........这里部分代码省略.........

func (r rctlParams) RollingUpdate(oldID, newID string, want, need int, pagerdutyServiceKey string) {
	if want < need {
		r.logger.WithFields(logrus.Fields{
			"want": want,
			"need": need,
		}).Fatalln("Cannot run update with desired replicas less than minimum replicas")
	}
	sessions := make(chan string)
	quit := make(chan struct{})

	go consulutil.SessionManager(api.SessionEntry{
		Name:      SessionName(),
		LockDelay: 5 * time.Second,
		Behavior:  api.SessionBehaviorDelete,
		TTL:       "15s",
	}, r.baseClient, sessions, quit, r.logger)

	sessionID := <-sessions
	if sessionID == "" {
		r.logger.NoFields().Fatalln("Could not acquire session")
	}
	session := r.kps.NewUnmanagedSession(sessionID, "")

	alerter := alerting.NewNop()
	if pagerdutyServiceKey != "" {
		var err error
		alerter, err = alerting.NewPagerduty(pagerdutyServiceKey, r.httpClient)
		if err != nil {
			r.logger.WithError(err).Fatalln("Could not initialize pagerduty alerter")
		}
	}

	result := make(chan bool, 1)
	go func() {
		result <- roll.NewUpdate(roll_fields.Update{
			OldRC:           rc_fields.ID(oldID),
			NewRC:           rc_fields.ID(newID),
			DesiredReplicas: want,
			MinimumReplicas: need,
		}, r.kps, r.rcs, r.hcheck, r.labeler, r.sched, r.logger, session, alerter).Run(quit)
		close(result)
	}()

	signals := make(chan os.Signal, 2)
	signal.Notify(signals, syscall.SIGTERM, os.Interrupt)

LOOP:
	for {
		select {
		case <-signals:
			// try to clean up locks on ^C
			close(quit)
			// do not exit right away - the session and result channels will be
			// closed after the quit is requested, ensuring that the locks held
			// by the farm were released.
			r.logger.NoFields().Errorln("Got signal, exiting")
		case <-sessions:
			r.logger.NoFields().Fatalln("Lost session")
		case res := <-result:
			// done, either due to ^C (already printed message above) or
			// clean finish
			if res {
				r.logger.NoFields().Infoln("Done")
			}
			break LOOP
		}
	}
}

func main() {
	// Parse custom flags + standard Consul routing options
	kingpin.Version(version.VERSION)
	_, opts := flags.ParseWithConsulOptions()

	// Set up the logger
	logger := logging.NewLogger(logrus.Fields{})
	logger.Logger.Formatter = new(logrus.TextFormatter)
	if *logLevel != "" {
		lv, err := logrus.ParseLevel(*logLevel)
		if err != nil {
			logger.WithErrorAndFields(err, logrus.Fields{"level": *logLevel}).
				Fatalln("Could not parse log level")
		}
		logger.Logger.Level = lv
	}

	// Initialize the myriad of different storage components
	httpClient := cleanhttp.DefaultClient()
	client := kp.NewConsulClient(opts)
	kpStore := kp.NewConsulStore(client)
	rcStore := rcstore.NewConsul(client, RetryCount)
	rollStore := rollstore.NewConsul(client, nil)
	healthChecker := checker.NewConsulHealthChecker(client)
	labeler := labels.NewConsulApplicator(client, RetryCount)
	var sched scheduler.Scheduler
	if *labelEndpoint != "" {
		endpoint, err := url.Parse(*labelEndpoint)
		if err != nil {
			logger.WithErrorAndFields(err, logrus.Fields{
				"url": *labelEndpoint,
			}).Fatalln("Could not parse URL from label endpoint")
		}
		httpLabeler, err := labels.NewHttpApplicator(opts.Client, endpoint)
		if err != nil {
			logger.WithError(err).Fatalln("Could not create label applicator from endpoint")
		}
		sched = scheduler.NewApplicatorScheduler(httpLabeler)
	} else {
		sched = scheduler.NewApplicatorScheduler(labeler)
	}

	// Start acquiring sessions
	sessions := make(chan string)
	go consulutil.SessionManager(api.SessionEntry{
		Name:      SessionName(),
		LockDelay: 5 * time.Second,
		Behavior:  api.SessionBehaviorDelete,
		TTL:       "15s",
	}, client, sessions, nil, logger)
	pub := stream.NewStringValuePublisher(sessions, "")

	alerter := alerting.NewNop()
	if *pagerdutyServiceKey != "" {
		var err error
		alerter, err = alerting.NewPagerduty(*pagerdutyServiceKey, httpClient)
		if err != nil {
			logger.WithError(err).Fatalln(
				"Unable to initialize pagerduty alerter",
			)
		}
	}

	// Run the farms!
	go rc.NewFarm(
		kpStore,
		rcStore,
		sched,
		labeler,
		pub.Subscribe().Chan(),
		logger,
		klabels.Everything(),
		alerter,
	).Start(nil)
	roll.NewFarm(
		roll.UpdateFactory{
			KPStore:       kpStore,
			RCStore:       rcStore,
			HealthChecker: healthChecker,
			Labeler:       labeler,
			Scheduler:     sched,
		},
		kpStore,
		rollStore,
		rcStore,
		pub.Subscribe().Chan(),
		logger,
		labeler,
		klabels.Everything(),
		alerter,
	).Start(nil)
}