// Start the container manager.
func (self *manager) Start() error {

	if *enableLoadReader {
		// Create cpu load reader.
		cpuLoadReader, err := cpuload.New()
		if err != nil {
			// TODO(rjnagal): Promote to warning once we support cpu load inside namespaces.
			glog.Infof("Could not initialize cpu load reader: %s", err)
		} else {
			err = cpuLoadReader.Start()
			if err != nil {
				glog.Warning("Could not start cpu load stat collector: %s", err)
			} else {
				self.loadReader = cpuLoadReader
			}
		}
	}

	// Watch for OOMs.
	err := self.watchForNewOoms()
	if err != nil {
		glog.Errorf("Failed to start OOM watcher, will not get OOM events: %v", err)
	}

	// If there are no factories, don't start any housekeeping and serve the information we do have.
	if !container.HasFactories() {
		return nil
	}

	// Create root and then recover all containers.
	err = self.createContainer("/")
	if err != nil {
		return err
	}
	glog.Infof("Starting recovery of all containers")
	err = self.detectSubcontainers("/")
	if err != nil {
		return err
	}
	glog.Infof("Recovery completed")

	// Watch for new container.
	quitWatcher := make(chan error)
	err = self.watchForNewContainers(quitWatcher)
	if err != nil {
		return err
	}
	self.quitChannels = append(self.quitChannels, quitWatcher)

	// Look for new containers in the main housekeeping thread.
	quitGlobalHousekeeping := make(chan error)
	self.quitChannels = append(self.quitChannels, quitGlobalHousekeeping)
	go self.globalHousekeeping(quitGlobalHousekeeping)

	return nil
}

// Start the container manager.
func (self *manager) Start() error {
	err := docker.Register(self, self.fsInfo, self.ignoreMetrics)
	if err != nil {
		glog.Errorf("Docker container factory registration failed: %v.", err)
	}

	err = rkt.Register(self, self.fsInfo, self.ignoreMetrics)
	if err != nil {
		glog.Errorf("Registration of the rkt container factory failed: %v", err)
	}

	err = systemd.Register(self, self.fsInfo, self.ignoreMetrics)
	if err != nil {
		glog.Errorf("Registration of the systemd container factory failed: %v", err)
	}

	err = raw.Register(self, self.fsInfo, self.ignoreMetrics)
	if err != nil {
		glog.Errorf("Registration of the raw container factory failed: %v", err)
	}

	self.DockerInfo()
	self.DockerImages()

	if *enableLoadReader {
		// Create cpu load reader.
		cpuLoadReader, err := cpuload.New()
		if err != nil {
			// TODO(rjnagal): Promote to warning once we support cpu load inside namespaces.
			glog.Infof("Could not initialize cpu load reader: %s", err)
		} else {
			err = cpuLoadReader.Start()
			if err != nil {
				glog.Warningf("Could not start cpu load stat collector: %s", err)
			} else {
				self.loadReader = cpuLoadReader
			}
		}
	}

	// Watch for OOMs.
	err = self.watchForNewOoms()
	if err != nil {
		glog.Warningf("Could not configure a source for OOM detection, disabling OOM events: %v", err)
	}

	// If there are no factories, don't start any housekeeping and serve the information we do have.
	if !container.HasFactories() {
		return nil
	}

	// Create root and then recover all containers.
	err = self.createContainer("/")
	if err != nil {
		return err
	}
	glog.Infof("Starting recovery of all containers")
	err = self.detectSubcontainers("/")
	if err != nil {
		return err
	}
	glog.Infof("Recovery completed")

	// Watch for new container.
	quitWatcher := make(chan error)
	err = self.watchForNewContainers(quitWatcher)
	if err != nil {
		return err
	}
	self.quitChannels = append(self.quitChannels, quitWatcher)

	// Look for new containers in the main housekeeping thread.
	quitGlobalHousekeeping := make(chan error)
	self.quitChannels = append(self.quitChannels, quitGlobalHousekeeping)
	go self.globalHousekeeping(quitGlobalHousekeeping)

	return nil
}

// Start the container manager.
func (self *manager) Start() error {
	err := docker.Register(self, self.fsInfo, self.ignoreMetrics)
	if err != nil {
		glog.Warningf("Docker container factory registration failed: %v.", err)
	}

	err = rkt.Register(self, self.fsInfo, self.ignoreMetrics)
	if err != nil {
		glog.Warningf("Registration of the rkt container factory failed: %v", err)
	} else {
		watcher, err := rktwatcher.NewRktContainerWatcher()
		if err != nil {
			return err
		}
		self.containerWatchers = append(self.containerWatchers, watcher)
	}

	err = systemd.Register(self, self.fsInfo, self.ignoreMetrics)
	if err != nil {
		glog.Warningf("Registration of the systemd container factory failed: %v", err)
	}

	err = raw.Register(self, self.fsInfo, self.ignoreMetrics)
	if err != nil {
		glog.Errorf("Registration of the raw container factory failed: %v", err)
	}

	rawWatcher, err := rawwatcher.NewRawContainerWatcher()
	if err != nil {
		return err
	}
	self.containerWatchers = append(self.containerWatchers, rawWatcher)

	// Watch for OOMs.
	err = self.watchForNewOoms()
	if err != nil {
		glog.Warningf("Could not configure a source for OOM detection, disabling OOM events: %v", err)
	}

	// If there are no factories, don't start any housekeeping and serve the information we do have.
	if !container.HasFactories() {
		return nil
	}

	// Create root and then recover all containers.
	err = self.createContainer("/", watcher.Raw)
	if err != nil {
		return err
	}
	glog.Infof("Starting recovery of all containers")
	err = self.detectSubcontainers("/")
	if err != nil {
		return err
	}
	glog.Infof("Recovery completed")

	// Watch for new container.
	quitWatcher := make(chan error)
	err = self.watchForNewContainers(quitWatcher)
	if err != nil {
		return err
	}
	self.quitChannels = append(self.quitChannels, quitWatcher)

	// Look for new containers in the main housekeeping thread.
	quitGlobalHousekeeping := make(chan error)
	self.quitChannels = append(self.quitChannels, quitGlobalHousekeeping)
	go self.globalHousekeeping(quitGlobalHousekeeping)

	return nil
}