libcontainerd: split client and supervisor

Adds a supervisor package for starting and monitoring containerd.
Separates grpc connection allowing access from daemon.

Signed-off-by: Derek McGowan <derek@mcgstyle.net>

14 files changed, 236 insertions, 423 deletions

diff --git a/libcontainerd/client_daemon.go b/libcontainerd/client_daemon.go
index 1bea770c29..2fa7d63b3f 100644
--- a/libcontainerd/client_daemon.go
+++ b/libcontainerd/client_daemon.go
@@ -102,38 +102,34 @@ func (c *container) getOOMKilled() bool {
 type client struct {
 	sync.RWMutex // protects containers map
 
-	remote   *containerd.Client
+	client   *containerd.Client
 	stateDir string
 	logger   *logrus.Entry
+	ns       string
 
-	namespace  string
 	backend    Backend
 	eventQ     queue
 	containers map[string]*container
 }
 
-func (c *client) reconnect() error {
-	c.Lock()
-	err := c.remote.Reconnect()
-	c.Unlock()
-	return err
-}
+// NewClient creates a new libcontainerd client from a containerd client
+func NewClient(ctx context.Context, cli *containerd.Client, stateDir, ns string, b Backend) (Client, error) {
+	c := &client{
+		client:     cli,
+		stateDir:   stateDir,
+		logger:     logrus.WithField("module", "libcontainerd").WithField("namespace", ns),
+		ns:         ns,
+		backend:    b,
+		containers: make(map[string]*container),
+	}
 
-func (c *client) setRemote(remote *containerd.Client) {
-	c.Lock()
-	c.remote = remote
-	c.Unlock()
-}
+	go c.processEventStream(ctx, ns)
 
-func (c *client) getRemote() *containerd.Client {
-	c.RLock()
-	remote := c.remote
-	c.RUnlock()
-	return remote
+	return c, nil
 }
 
 func (c *client) Version(ctx context.Context) (containerd.Version, error) {
-	return c.getRemote().Version(ctx)
+	return c.client.Version(ctx)
 }
 
 // Restore loads the containerd container.
@@ -170,7 +166,7 @@ func (c *client) Restore(ctx context.Context, id string, attachStdio StdioCallba
 		err = wrapError(err)
 	}()
 
-	ctr, err := c.getRemote().LoadContainer(ctx, id)
+	ctr, err := c.client.LoadContainer(ctx, id)
 	if err != nil {
 		return false, -1, errors.WithStack(wrapError(err))
 	}
@@ -225,7 +221,7 @@ func (c *client) Create(ctx context.Context, id string, ociSpec *specs.Spec, run
 
 	c.logger.WithField("bundle", bdir).WithField("root", ociSpec.Root.Path).Debug("bundle dir created")
 
-	cdCtr, err := c.getRemote().NewContainer(ctx, id,
+	cdCtr, err := c.client.NewContainer(ctx, id,
 		containerd.WithSpec(ociSpec),
 		// TODO(mlaventure): when containerd support lcow, revisit runtime value
 		containerd.WithRuntime(fmt.Sprintf("io.containerd.runtime.v1.%s", runtime.GOOS), runtimeOptions))
@@ -268,7 +264,7 @@ func (c *client) Start(ctx context.Context, id, checkpointDir string, withStdin
 		// remove the checkpoint when we're done
 		defer func() {
 			if cp != nil {
-				err := c.getRemote().ContentStore().Delete(context.Background(), cp.Digest)
+				err := c.client.ContentStore().Delete(context.Background(), cp.Digest)
 				if err != nil {
 					c.logger.WithError(err).WithFields(logrus.Fields{
 						"ref":    checkpointDir,
@@ -571,14 +567,14 @@ func (c *client) CreateCheckpoint(ctx context.Context, containerID, checkpointDi
 	}
 	// Whatever happens, delete the checkpoint from containerd
 	defer func() {
-		err := c.getRemote().ImageService().Delete(context.Background(), img.Name())
+		err := c.client.ImageService().Delete(context.Background(), img.Name())
 		if err != nil {
 			c.logger.WithError(err).WithField("digest", img.Target().Digest).
 				Warnf("failed to delete checkpoint image")
 		}
 	}()
 
-	b, err := content.ReadBlob(ctx, c.getRemote().ContentStore(), img.Target())
+	b, err := content.ReadBlob(ctx, c.client.ContentStore(), img.Target())
 	if err != nil {
 		return errdefs.System(errors.Wrapf(err, "failed to retrieve checkpoint data"))
 	}
@@ -598,7 +594,7 @@ func (c *client) CreateCheckpoint(ctx context.Context, containerID, checkpointDi
 		return errdefs.System(errors.Wrapf(err, "invalid checkpoint"))
 	}
 
-	rat, err := c.getRemote().ContentStore().ReaderAt(ctx, *cpDesc)
+	rat, err := c.client.ContentStore().ReaderAt(ctx, *cpDesc)
 	if err != nil {
 		return errdefs.System(errors.Wrapf(err, "failed to get checkpoint reader"))
 	}
@@ -735,7 +731,7 @@ func (c *client) processEvent(ctr *container, et EventType, ei EventInfo) {
 	})
 }
 
-func (c *client) processEventStream(ctx context.Context) {
+func (c *client) processEventStream(ctx context.Context, ns string) {
 	var (
 		err error
 		ev  *events.Envelope
@@ -746,9 +742,9 @@ func (c *client) processEventStream(ctx context.Context) {
 
 	// Filter on both namespace *and* topic. To create an "and" filter,
 	// this must be a single, comma-separated string
-	eventStream, errC := c.getRemote().EventService().Subscribe(ctx, "namespace=="+c.namespace+",topic~=|^/tasks/|")
+	eventStream, errC := c.client.EventService().Subscribe(ctx, "namespace=="+ns+",topic~=|^/tasks/|")
 
-	c.logger.WithField("namespace", c.namespace).Debug("processing event stream")
+	c.logger.Debug("processing event stream")
 
 	var oomKilled bool
 	for {
@@ -758,7 +754,7 @@ func (c *client) processEventStream(ctx context.Context) {
 				errStatus, ok := status.FromError(err)
 				if !ok || errStatus.Code() != codes.Canceled {
 					c.logger.WithError(err).Error("failed to get event")
-					go c.processEventStream(ctx)
+					go c.processEventStream(ctx, ns)
 				} else {
 					c.logger.WithError(ctx.Err()).Info("stopping event stream following graceful shutdown")
 				}
@@ -858,7 +854,7 @@ func (c *client) processEventStream(ctx context.Context) {
 }
 
 func (c *client) writeContent(ctx context.Context, mediaType, ref string, r io.Reader) (*types.Descriptor, error) {
-	writer, err := c.getRemote().ContentStore().Writer(ctx, content.WithRef(ref))
+	writer, err := c.client.ContentStore().Writer(ctx, content.WithRef(ref))
 	if err != nil {
 		return nil, err
 	}
diff --git a/libcontainerd/client_local_windows.go b/libcontainerd/client_local_windows.go
index 89d18c6ba7..85f0c18584 100644
--- a/libcontainerd/client_local_windows.go
+++ b/libcontainerd/client_local_windows.go
@@ -71,6 +71,28 @@ const (
 // of docker.
 const defaultOwner = "docker"
 
+type client struct {
+	sync.Mutex
+
+	stateDir   string
+	backend    Backend
+	logger     *logrus.Entry
+	eventQ     queue
+	containers map[string]*container
+}
+
+// NewClient creates a new local executor for windows
+func NewClient(ctx context.Context, cli *containerd.Client, stateDir, ns string, b Backend) (Client, error) {
+	c := &client{
+		stateDir:   stateDir,
+		backend:    b,
+		logger:     logrus.WithField("module", "libcontainerd").WithField("module", "libcontainerd").WithField("namespace", ns),
+		containers: make(map[string]*container),
+	}
+
+	return c, nil
+}
+
 func (c *client) Version(ctx context.Context) (containerd.Version, error) {
 	return containerd.Version{}, errors.New("not implemented on Windows")
 }
diff --git a/libcontainerd/remote_daemon_options.go b/libcontainerd/remote_daemon_options.go
deleted file mode 100644
index f035756ed5..0000000000
--- a/libcontainerd/remote_daemon_options.go
+++ /dev/null
@@ -1,142 +0,0 @@
-// +build !windows
-
-package libcontainerd // import "github.com/docker/docker/libcontainerd"
-
-import "fmt"
-
-// WithRemoteAddr sets the external containerd socket to connect to.
-func WithRemoteAddr(addr string) RemoteOption {
-	return rpcAddr(addr)
-}
-
-type rpcAddr string
-
-func (a rpcAddr) Apply(r Remote) error {
-	if remote, ok := r.(*remote); ok {
-		remote.GRPC.Address = string(a)
-		return nil
-	}
-	return fmt.Errorf("WithRemoteAddr option not supported for this remote")
-}
-
-// WithRemoteAddrUser sets the uid and gid to create the RPC address with
-func WithRemoteAddrUser(uid, gid int) RemoteOption {
-	return rpcUser{uid, gid}
-}
-
-type rpcUser struct {
-	uid int
-	gid int
-}
-
-func (u rpcUser) Apply(r Remote) error {
-	if remote, ok := r.(*remote); ok {
-		remote.GRPC.UID = u.uid
-		remote.GRPC.GID = u.gid
-		return nil
-	}
-	return fmt.Errorf("WithRemoteAddr option not supported for this remote")
-}
-
-// WithStartDaemon defines if libcontainerd should also run containerd daemon.
-func WithStartDaemon(start bool) RemoteOption {
-	return startDaemon(start)
-}
-
-type startDaemon bool
-
-func (s startDaemon) Apply(r Remote) error {
-	if remote, ok := r.(*remote); ok {
-		remote.startDaemon = bool(s)
-		return nil
-	}
-	return fmt.Errorf("WithStartDaemon option not supported for this remote")
-}
-
-// WithLogLevel defines which log level to starts containerd with.
-// This only makes sense if WithStartDaemon() was set to true.
-func WithLogLevel(lvl string) RemoteOption {
-	return logLevel(lvl)
-}
-
-type logLevel string
-
-func (l logLevel) Apply(r Remote) error {
-	if remote, ok := r.(*remote); ok {
-		remote.Debug.Level = string(l)
-		return nil
-	}
-	return fmt.Errorf("WithDebugLog option not supported for this remote")
-}
-
-// WithDebugAddress defines at which location the debug GRPC connection
-// should be made
-func WithDebugAddress(addr string) RemoteOption {
-	return debugAddress(addr)
-}
-
-type debugAddress string
-
-func (d debugAddress) Apply(r Remote) error {
-	if remote, ok := r.(*remote); ok {
-		remote.Debug.Address = string(d)
-		return nil
-	}
-	return fmt.Errorf("WithDebugAddress option not supported for this remote")
-}
-
-// WithMetricsAddress defines at which location the debug GRPC connection
-// should be made
-func WithMetricsAddress(addr string) RemoteOption {
-	return metricsAddress(addr)
-}
-
-type metricsAddress string
-
-func (m metricsAddress) Apply(r Remote) error {
-	if remote, ok := r.(*remote); ok {
-		remote.Metrics.Address = string(m)
-		return nil
-	}
-	return fmt.Errorf("WithMetricsAddress option not supported for this remote")
-}
-
-// WithSnapshotter defines snapshotter driver should be used
-func WithSnapshotter(name string) RemoteOption {
-	return snapshotter(name)
-}
-
-type snapshotter string
-
-func (s snapshotter) Apply(r Remote) error {
-	if remote, ok := r.(*remote); ok {
-		remote.snapshotter = string(s)
-		return nil
-	}
-	return fmt.Errorf("WithSnapshotter option not supported for this remote")
-}
-
-// WithPlugin allow configuring a containerd plugin
-// configuration values passed needs to be quoted if quotes are needed in
-// the toml format.
-// Setting the config to nil will disable a built-in plugin
-func WithPlugin(name string, conf interface{}) RemoteOption {
-	return pluginConf{
-		name: name,
-		conf: conf,
-	}
-}
-
-type pluginConf struct {
-	// Name is the name of the plugin
-	name string
-	conf interface{}
-}
-
-func (p pluginConf) Apply(r Remote) error {
-	if remote, ok := r.(*remote); ok {
-		remote.pluginConfs.Plugins[p.name] = p.conf
-		return nil
-	}
-	return fmt.Errorf("WithPlugin option not supported for this remote")
-}
diff --git a/libcontainerd/remote_daemon_options_linux.go b/libcontainerd/remote_daemon_options_linux.go
deleted file mode 100644
index a820fb3894..0000000000
--- a/libcontainerd/remote_daemon_options_linux.go
+++ /dev/null
@@ -1,18 +0,0 @@
-package libcontainerd // import "github.com/docker/docker/libcontainerd"
-
-import "fmt"
-
-// WithOOMScore defines the oom_score_adj to set for the containerd process.
-func WithOOMScore(score int) RemoteOption {
-	return oomScore(score)
-}
-
-type oomScore int
-
-func (o oomScore) Apply(r Remote) error {
-	if remote, ok := r.(*remote); ok {
-		remote.OOMScore = int(o)
-		return nil
-	}
-	return fmt.Errorf("WithOOMScore option not supported for this remote")
-}
diff --git a/libcontainerd/remote_local.go b/libcontainerd/remote_local.go
deleted file mode 100644
index 8ea5198b87..0000000000
--- a/libcontainerd/remote_local.go
+++ /dev/null
@@ -1,59 +0,0 @@
-// +build windows
-
-package libcontainerd // import "github.com/docker/docker/libcontainerd"
-
-import (
-	"sync"
-
-	"github.com/sirupsen/logrus"
-)
-
-type remote struct {
-	sync.RWMutex
-
-	logger  *logrus.Entry
-	clients []*client
-
-	// Options
-	rootDir  string
-	stateDir string
-}
-
-// New creates a fresh instance of libcontainerd remote.
-func New(rootDir, stateDir string, options ...RemoteOption) (Remote, error) {
-	return &remote{
-		logger:   logrus.WithField("module", "libcontainerd"),
-		rootDir:  rootDir,
-		stateDir: stateDir,
-	}, nil
-}
-
-type client struct {
-	sync.Mutex
-
-	rootDir    string
-	stateDir   string
-	backend    Backend
-	logger     *logrus.Entry
-	eventQ     queue
-	containers map[string]*container
-}
-
-func (r *remote) NewClient(ns string, b Backend) (Client, error) {
-	c := &client{
-		rootDir:    r.rootDir,
-		stateDir:   r.stateDir,
-		backend:    b,
-		logger:     r.logger.WithField("namespace", ns),
-		containers: make(map[string]*container),
-	}
-	r.Lock()
-	r.clients = append(r.clients, c)
-	r.Unlock()
-
-	return c, nil
-}
-
-func (r *remote) Cleanup() {
-	// Nothing to do
-}
diff --git a/libcontainerd/remote_daemon.go b/libcontainerd/supervisor/remote_daemon.go
index 07c0ea6bc6..b520d48671 100644
--- a/libcontainerd/remote_daemon.go
+++ b/libcontainerd/supervisor/remote_daemon.go
@@ -1,6 +1,4 @@
-// +build !windows
-
-package libcontainerd // import "github.com/docker/docker/libcontainerd"
+package supervisor // import "github.com/docker/docker/libcontainerd/supervisor"
 
 import (
 	"context"
@@ -13,7 +11,6 @@ import (
 	"strconv"
 	"strings"
 	"sync"
-	"syscall"
 	"time"
 
 	"github.com/BurntSushi/toml"
@@ -28,6 +25,7 @@ const (
 	maxConnectionRetryCount = 3
 	healthCheckTimeout      = 3 * time.Second
 	shutdownTimeout         = 15 * time.Second
+	startupTimeout          = 15 * time.Second
 	configFile              = "containerd.toml"
 	binaryName              = "docker-containerd"
 	pidFile                 = "docker-containerd.pid"
@@ -44,28 +42,26 @@ type remote struct {
 	daemonPid int
 	logger    *logrus.Entry
 
-	daemonWaitCh    chan struct{}
-	clients         []*client
-	shutdownContext context.Context
-	shutdownCancel  context.CancelFunc
-	shutdown        bool
+	daemonWaitCh  chan struct{}
+	daemonStartCh chan struct{}
+	daemonStopCh  chan struct{}
 
-	// Options
-	startDaemon bool
 	rootDir     string
 	stateDir    string
-	snapshotter string
 	pluginConfs pluginConfigs
 }
 
-// New creates a fresh instance of libcontainerd remote.
-func New(rootDir, stateDir string, options ...RemoteOption) (rem Remote, err error) {
-	defer func() {
-		if err != nil {
-			err = errors.Wrap(err, "Failed to connect to containerd")
-		}
-	}()
+// Daemon represents a running containerd daemon
+type Daemon interface {
+	WaitTimeout(time.Duration) error
+	Address() string
+}
+
+// DaemonOpt allows to configure parameters of container daemons
+type DaemonOpt func(c *remote) error
 
+// Start starts a containerd daemon and monitors it
+func Start(ctx context.Context, rootDir, stateDir string, opts ...DaemonOpt) (Daemon, error) {
 	r := &remote{
 		rootDir:  rootDir,
 		stateDir: stateDir,
@@ -73,86 +69,47 @@ func New(rootDir, stateDir string, options ...RemoteOption) (rem Remote, err err
 			Root:  filepath.Join(rootDir, "daemon"),
 			State: filepath.Join(stateDir, "daemon"),
 		},
-		pluginConfs: pluginConfigs{make(map[string]interface{})},
-		daemonPid:   -1,
-		logger:      logrus.WithField("module", "libcontainerd"),
+		pluginConfs:   pluginConfigs{make(map[string]interface{})},
+		daemonPid:     -1,
+		logger:        logrus.WithField("module", "libcontainerd"),
+		daemonStartCh: make(chan struct{}),
+		daemonStopCh:  make(chan struct{}),
 	}
-	r.shutdownContext, r.shutdownCancel = context.WithCancel(context.Background())
 
-	rem = r
-	for _, option := range options {
-		if err = option.Apply(r); err != nil {
-			return
+	for _, opt := range opts {
+		if err := opt(r); err != nil {
+			return nil, err
 		}
 	}
 	r.setDefaults()
 
-	if err = system.MkdirAll(stateDir, 0700, ""); err != nil {
-		return
+	if err := system.MkdirAll(stateDir, 0700, ""); err != nil {
+		return nil, err
 	}
 
-	if r.startDaemon {
-		os.Remove(r.GRPC.Address)
-		if err = r.startContainerd(); err != nil {
-			return
-		}
-		defer func() {
-			if err != nil {
-				r.Cleanup()
-			}
-		}()
-	}
+	go r.monitorDaemon(ctx)
 
-	// This connection is just used to monitor the connection
-	client, err := containerd.New(r.GRPC.Address)
-	if err != nil {
-		return
-	}
-	if _, err := client.Version(context.Background()); err != nil {
-		system.KillProcess(r.daemonPid)
-		return nil, errors.Wrapf(err, "unable to get containerd version")
+	select {
+	case <-time.After(startupTimeout):
+		return nil, errors.New("timeout waiting for containerd to start")
+	case <-r.daemonStartCh:
 	}
 
-	go r.monitorConnection(client)
-
 	return r, nil
 }
-
-func (r *remote) NewClient(ns string, b Backend) (Client, error) {
-	c := &client{
-		stateDir:   r.stateDir,
-		logger:     r.logger.WithField("namespace", ns),
-		namespace:  ns,
-		backend:    b,
-		containers: make(map[string]*container),
+func (r *remote) WaitTimeout(d time.Duration) error {
+	select {
+	case <-time.After(d):
+		return errors.New("timeout waiting for containerd to stop")
+	case <-r.daemonStopCh:
 	}
 
-	rclient, err := containerd.New(r.GRPC.Address, containerd.WithDefaultNamespace(ns))
-	if err != nil {
-		return nil, err
-	}
-	c.remote = rclient
-
-	go c.processEventStream(r.shutdownContext)
-
-	r.Lock()
-	r.clients = append(r.clients, c)
-	r.Unlock()
-	return c, nil
+	return nil
 }
 
-func (r *remote) Cleanup() {
-	if r.daemonPid != -1 {
-		r.shutdownCancel()
-		r.stopDaemon()
-	}
-
-	// cleanup some files
-	os.Remove(filepath.Join(r.stateDir, pidFile))
-
-	r.platformCleanup()
+func (r *remote) Address() string {
+	return r.GRPC.Address
 }
-
 func (r *remote) getContainerdPid() (int, error) {
 	pidFile := filepath.Join(r.stateDir, pidFile)
 	f, err := os.OpenFile(pidFile, os.O_RDWR, 0600)
@@ -265,85 +222,90 @@ func (r *remote) startContainerd() error {
 	return nil
 }
 
-func (r *remote) monitorConnection(monitor *containerd.Client) {
-	var transientFailureCount = 0
+func (r *remote) monitorDaemon(ctx context.Context) {
+	var (
+		transientFailureCount = 0
+		client                *containerd.Client
+		err                   error
+		delay                 <-chan time.Time
+		started               bool
+	)
+
+	defer func() {
+		if r.daemonPid != -1 {
+			r.stopDaemon()
+		}
+
+		// cleanup some files
+		os.Remove(filepath.Join(r.stateDir, pidFile))
+
+		r.platformCleanup()
+
+		close(r.daemonStopCh)
+	}()
 
 	for {
 		select {
-		case <-r.shutdownContext.Done():
+		case <-ctx.Done():
 			r.logger.Info("stopping healthcheck following graceful shutdown")
-			monitor.Close()
+			if client != nil {
+				client.Close()
+			}
 			return
-		case <-time.After(500 * time.Millisecond):
+		case <-delay:
+		default:
+		}
+
+		if r.daemonPid == -1 {
+			if r.daemonWaitCh != nil {
+				<-r.daemonWaitCh
+			}
+
+			os.RemoveAll(r.GRPC.Address)
+			if err := r.startContainerd(); err != nil {
+				r.logger.WithError(err).Error("failed starting containerd")
+				delay = time.After(50 * time.Millisecond)
+				continue
+			}
+
+			client, err = containerd.New(r.GRPC.Address)
+			if err != nil {
+				r.logger.WithError(err).Error("failed connecting to containerd")
+				delay = time.After(100 * time.Millisecond)
+				continue
+			}
 		}
 
-		ctx, cancel := context.WithTimeout(r.shutdownContext, healthCheckTimeout)
-		_, err := monitor.IsServing(ctx)
+		tctx, cancel := context.WithTimeout(ctx, healthCheckTimeout)
+		_, err := client.IsServing(tctx)
 		cancel()
 		if err == nil {
+			if !started {
+				close(r.daemonStartCh)
+				started = true
+			}
+
 			transientFailureCount = 0
+			delay = time.After(500 * time.Millisecond)
 			continue
 		}
 
-		select {
-		case <-r.shutdownContext.Done():
-			r.logger.Info("stopping healthcheck following graceful shutdown")
-			monitor.Close()
-			return
-		default:
-		}
-
 		r.logger.WithError(err).WithField("binary", binaryName).Debug("daemon is not responding")
 
-		if r.daemonPid == -1 {
-			continue
-		}
-
 		transientFailureCount++
 		if transientFailureCount < maxConnectionRetryCount || system.IsProcessAlive(r.daemonPid) {
+			delay = time.After(time.Duration(transientFailureCount) * 200 * time.Millisecond)
 			continue
 		}
 
-		transientFailureCount = 0
 		if system.IsProcessAlive(r.daemonPid) {
 			r.logger.WithField("pid", r.daemonPid).Info("killing and restarting containerd")
-			// Try to get a stack trace
-			syscall.Kill(r.daemonPid, syscall.SIGUSR1)
-			<-time.After(100 * time.Millisecond)
-			system.KillProcess(r.daemonPid)
-		}
-		if r.daemonWaitCh != nil {
-			<-r.daemonWaitCh
-		}
-
-		os.Remove(r.GRPC.Address)
-		if err := r.startContainerd(); err != nil {
-			r.logger.WithError(err).Error("failed restarting containerd")
-			continue
+			r.killDaemon()
 		}
 
-		if err := monitor.Reconnect(); err != nil {
-			r.logger.WithError(err).Error("failed connect to containerd")
-			continue
-		}
-
-		var wg sync.WaitGroup
-
-		for _, c := range r.clients {
-			wg.Add(1)
-
-			go func(c *client) {
-				defer wg.Done()
-				c.logger.WithField("namespace", c.namespace).Debug("creating new containerd remote client")
-				if err := c.reconnect(); err != nil {
-					r.logger.WithError(err).Error("failed to connect to containerd")
-					// TODO: Better way to handle this?
-					// This *shouldn't* happen, but this could wind up where the daemon
-					// is not able to communicate with an eventually up containerd
-				}
-			}(c)
-
-			wg.Wait()
-		}
+		client.Close()
+		r.daemonPid = -1
+		delay = nil
+		transientFailureCount = 0
 	}
 }
diff --git a/libcontainerd/remote_daemon_linux.go b/libcontainerd/supervisor/remote_daemon_linux.go
index e3d9640cea..1ea91d2b5d 100644
--- a/libcontainerd/remote_daemon_linux.go
+++ b/libcontainerd/supervisor/remote_daemon_linux.go
@@ -1,4 +1,4 @@
-package libcontainerd // import "github.com/docker/docker/libcontainerd"
+package supervisor // import "github.com/docker/docker/libcontainerd/supervisor"
 
 import (
 	"os"
@@ -38,10 +38,6 @@ func (r *remote) setDefaults() {
 			delete(r.pluginConfs.Plugins, key)
 		}
 	}
-
-	if r.snapshotter == "" {
-		r.snapshotter = "overlay"
-	}
 }
 
 func (r *remote) stopDaemon() {
@@ -61,6 +57,13 @@ func (r *remote) stopDaemon() {
 	}
 }
 
+func (r *remote) killDaemon() {
+	// Try to get a stack trace
+	syscall.Kill(r.daemonPid, syscall.SIGUSR1)
+	<-time.After(100 * time.Millisecond)
+	system.KillProcess(r.daemonPid)
+}
+
 func (r *remote) platformCleanup() {
 	os.Remove(filepath.Join(r.stateDir, sockFile))
 }
diff --git a/libcontainerd/supervisor/remote_daemon_options.go b/libcontainerd/supervisor/remote_daemon_options.go
new file mode 100644
index 0000000000..4c9387d6ce
--- /dev/null
+++ b/libcontainerd/supervisor/remote_daemon_options.go
@@ -0,0 +1,55 @@
+package supervisor // import "github.com/docker/docker/libcontainerd/supervisor"
+
+// WithRemoteAddr sets the external containerd socket to connect to.
+func WithRemoteAddr(addr string) DaemonOpt {
+	return func(r *remote) error {
+		r.GRPC.Address = addr
+		return nil
+	}
+}
+
+// WithRemoteAddrUser sets the uid and gid to create the RPC address with
+func WithRemoteAddrUser(uid, gid int) DaemonOpt {
+	return func(r *remote) error {
+		r.GRPC.UID = uid
+		r.GRPC.GID = gid
+		return nil
+	}
+}
+
+// WithLogLevel defines which log level to starts containerd with.
+// This only makes sense if WithStartDaemon() was set to true.
+func WithLogLevel(lvl string) DaemonOpt {
+	return func(r *remote) error {
+		r.Debug.Level = lvl
+		return nil
+	}
+}
+
+// WithDebugAddress defines at which location the debug GRPC connection
+// should be made
+func WithDebugAddress(addr string) DaemonOpt {
+	return func(r *remote) error {
+		r.Debug.Address = addr
+		return nil
+	}
+}
+
+// WithMetricsAddress defines at which location the debug GRPC connection
+// should be made
+func WithMetricsAddress(addr string) DaemonOpt {
+	return func(r *remote) error {
+		r.Metrics.Address = addr
+		return nil
+	}
+}
+
+// WithPlugin allow configuring a containerd plugin
+// configuration values passed needs to be quoted if quotes are needed in
+// the toml format.
+func WithPlugin(name string, conf interface{}) DaemonOpt {
+	return func(r *remote) error {
+		r.pluginConfs.Plugins[name] = conf
+		return nil
+	}
+}
diff --git a/libcontainerd/supervisor/remote_daemon_options_linux.go b/libcontainerd/supervisor/remote_daemon_options_linux.go
new file mode 100644
index 0000000000..14511dbf93
--- /dev/null
+++ b/libcontainerd/supervisor/remote_daemon_options_linux.go
@@ -0,0 +1,9 @@
+package supervisor // import "github.com/docker/docker/libcontainerd/supervisor"
+
+// WithOOMScore defines the oom_score_adj to set for the containerd process.
+func WithOOMScore(score int) DaemonOpt {
+	return func(r *remote) error {
+		r.OOMScore = score
+		return nil
+	}
+}
diff --git a/libcontainerd/remote_daemon_windows.go b/libcontainerd/supervisor/remote_daemon_windows.go
index 69cd1ac30c..bcdc9529e0 100644
--- a/libcontainerd/remote_daemon_windows.go
+++ b/libcontainerd/supervisor/remote_daemon_windows.go
@@ -1,9 +1,9 @@
-// +build remote_daemon
-
-package libcontainerd // import "github.com/docker/docker/libcontainerd"
+package supervisor // import "github.com/docker/docker/libcontainerd/supervisor"
 
 import (
 	"os"
+
+	"github.com/docker/docker/pkg/system"
 )
 
 const (
@@ -18,9 +18,6 @@ func (r *remote) setDefaults() {
 	if r.Debug.Address == "" {
 		r.Debug.Address = debugPipeName
 	}
-	if r.snapshotter == "" {
-		r.snapshotter = "naive" // TODO(mlaventure): switch to "windows" once implemented
-	}
 }
 
 func (r *remote) stopDaemon() {
@@ -42,6 +39,10 @@ func (r *remote) stopDaemon() {
 	}
 }
 
+func (r *remote) killDaemon() {
+	system.KillProcess(r.daemonPid)
+}
+
 func (r *remote) platformCleanup() {
 	// Nothing to do
 }
diff --git a/libcontainerd/utils_linux.go b/libcontainerd/supervisor/utils_linux.go
index ce17d1963d..32ac27f327 100644
--- a/libcontainerd/utils_linux.go
+++ b/libcontainerd/supervisor/utils_linux.go
@@ -1,4 +1,4 @@
-package libcontainerd // import "github.com/docker/docker/libcontainerd"
+package supervisor // import "github.com/docker/docker/libcontainerd/supervisor"
 
 import "syscall"
 
diff --git a/libcontainerd/supervisor/utils_windows.go b/libcontainerd/supervisor/utils_windows.go
new file mode 100644
index 0000000000..987d32bd23
--- /dev/null
+++ b/libcontainerd/supervisor/utils_windows.go
@@ -0,0 +1,9 @@
+package supervisor // import "github.com/docker/docker/libcontainerd/supervisor"
+
+import "syscall"
+
+// containerdSysProcAttr returns the SysProcAttr to use when exec'ing
+// containerd
+func containerdSysProcAttr() *syscall.SysProcAttr {
+	return nil
+}
diff --git a/libcontainerd/types.go b/libcontainerd/types.go
index 96ffbe2676..c4de5e674d 100644
--- a/libcontainerd/types.go
+++ b/libcontainerd/types.go
@@ -46,23 +46,6 @@ const (
 	StatusUnknown Status = "unknown"
 )
 
-// Remote on Linux defines the accesspoint to the containerd grpc API.
-// Remote on Windows is largely an unimplemented interface as there is
-// no remote containerd.
-type Remote interface {
-	// Client returns a new Client instance connected with given Backend.
-	NewClient(namespace string, backend Backend) (Client, error)
-	// Cleanup stops containerd if it was started by libcontainerd.
-	// Note this is not used on Windows as there is no remote containerd.
-	Cleanup()
-}
-
-// RemoteOption allows to configure parameters of remotes.
-// This is unused on Windows.
-type RemoteOption interface {
-	Apply(Remote) error
-}
-
 // EventInfo contains the event info
 type EventInfo struct {
 	ContainerID string
diff --git a/libcontainerd/utils_windows.go b/libcontainerd/utils_windows.go
index fbf243d4f9..aabb9aeaaa 100644
--- a/libcontainerd/utils_windows.go
+++ b/libcontainerd/utils_windows.go
@@ -3,8 +3,6 @@ package libcontainerd // import "github.com/docker/docker/libcontainerd"
 import (
 	"strings"
 
-	"syscall"
-
 	opengcs "github.com/Microsoft/opengcs/client"
 )
 
@@ -38,9 +36,3 @@ func (c *container) debugGCS() {
 	}
 	cfg.DebugGCS()
 }
-
-// containerdSysProcAttr returns the SysProcAttr to use when exec'ing
-// containerd
-func containerdSysProcAttr() *syscall.SysProcAttr {
-	return nil
-}