Initial checkin from CRI-O repo

Signed-off-by: Matthew Heon <matthew.heon@gmail.com>

1 files changed, 748 insertions, 0 deletions

diff --git a/oci/oci.go b/oci/oci.go
new file mode 100644
index 000000000..756be44bf
--- /dev/null
+++ b/oci/oci.go
@@ -0,0 +1,748 @@
+package oci
+
+import (
+	"bytes"
+	"encoding/json"
+	"fmt"
+	"io/ioutil"
+	"os"
+	"os/exec"
+	"path/filepath"
+	"strconv"
+	"strings"
+	"syscall"
+	"time"
+
+	"github.com/containerd/cgroups"
+	"github.com/kubernetes-incubator/cri-o/utils"
+	rspec "github.com/opencontainers/runtime-spec/specs-go"
+	"github.com/sirupsen/logrus"
+	"golang.org/x/net/context"
+	"golang.org/x/sys/unix"
+	kwait "k8s.io/apimachinery/pkg/util/wait"
+)
+
+const (
+	// ContainerStateCreated represents the created state of a container
+	ContainerStateCreated = "created"
+	// ContainerStatePaused represents the paused state of a container
+	ContainerStatePaused = "paused"
+	// ContainerStateRunning represents the running state of a container
+	ContainerStateRunning = "running"
+	// ContainerStateStopped represents the stopped state of a container
+	ContainerStateStopped = "stopped"
+	// ContainerCreateTimeout represents the value of container creating timeout
+	ContainerCreateTimeout = 240 * time.Second
+
+	// CgroupfsCgroupsManager represents cgroupfs native cgroup manager
+	CgroupfsCgroupsManager = "cgroupfs"
+	// SystemdCgroupsManager represents systemd native cgroup manager
+	SystemdCgroupsManager = "systemd"
+	// ContainerExitsDir is the location of container exit dirs
+	ContainerExitsDir = "/var/run/crio/exits"
+	// ContainerAttachSocketDir is the location for container attach sockets
+	ContainerAttachSocketDir = "/var/run/crio"
+
+	// killContainerTimeout is the timeout that we wait for the container to
+	// be SIGKILLed.
+	killContainerTimeout = 2 * time.Minute
+)
+
+// New creates a new Runtime with options provided
+func New(runtimeTrustedPath string,
+	runtimeUntrustedPath string,
+	trustLevel string,
+	conmonPath string,
+	conmonEnv []string,
+	cgroupManager string,
+	containerExitsDir string,
+	logSizeMax int64,
+	noPivot bool) (*Runtime, error) {
+	r := &Runtime{
+		name:              filepath.Base(runtimeTrustedPath),
+		trustedPath:       runtimeTrustedPath,
+		untrustedPath:     runtimeUntrustedPath,
+		trustLevel:        trustLevel,
+		conmonPath:        conmonPath,
+		conmonEnv:         conmonEnv,
+		cgroupManager:     cgroupManager,
+		containerExitsDir: containerExitsDir,
+		logSizeMax:        logSizeMax,
+		noPivot:           noPivot,
+	}
+	return r, nil
+}
+
+// Runtime stores the information about a oci runtime
+type Runtime struct {
+	name              string
+	trustedPath       string
+	untrustedPath     string
+	trustLevel        string
+	conmonPath        string
+	conmonEnv         []string
+	cgroupManager     string
+	containerExitsDir string
+	logSizeMax        int64
+	noPivot           bool
+}
+
+// syncInfo is used to return data from monitor process to daemon
+type syncInfo struct {
+	Pid     int    `json:"pid"`
+	Message string `json:"message,omitempty"`
+}
+
+// exitCodeInfo is used to return the monitored process exit code to the daemon
+type exitCodeInfo struct {
+	ExitCode int32  `json:"exit_code"`
+	Message  string `json:"message,omitempty"`
+}
+
+// Name returns the name of the OCI Runtime
+func (r *Runtime) Name() string {
+	return r.name
+}
+
+// Path returns the full path the OCI Runtime executable.
+// Depending if the container is privileged and/or trusted,
+// this will return either the trusted or untrusted runtime path.
+func (r *Runtime) Path(c *Container) string {
+	if !c.trusted {
+		// We have an explicitly untrusted container.
+		if c.privileged {
+			logrus.Warnf("Running an untrusted but privileged container")
+			return r.trustedPath
+		}
+
+		if r.untrustedPath != "" {
+			return r.untrustedPath
+		}
+
+		return r.trustedPath
+	}
+
+	// Our container is trusted. Let's look at the configured trust level.
+	if r.trustLevel == "trusted" {
+		return r.trustedPath
+	}
+
+	// Our container is trusted, but we are running untrusted.
+	// We will use the untrusted container runtime if it's set
+	// and if it's not a privileged container.
+	if c.privileged || r.untrustedPath == "" {
+		return r.trustedPath
+	}
+
+	return r.untrustedPath
+}
+
+// Version returns the version of the OCI Runtime
+func (r *Runtime) Version() (string, error) {
+	runtimeVersion, err := getOCIVersion(r.trustedPath, "-v")
+	if err != nil {
+		return "", err
+	}
+	return runtimeVersion, nil
+}
+
+func getOCIVersion(name string, args ...string) (string, error) {
+	out, err := utils.ExecCmd(name, args...)
+	if err != nil {
+		return "", err
+	}
+
+	firstLine := out[:strings.Index(out, "\n")]
+	v := firstLine[strings.LastIndex(firstLine, " ")+1:]
+	return v, nil
+}
+
+// CreateContainer creates a container.
+func (r *Runtime) CreateContainer(c *Container, cgroupParent string) (err error) {
+	var stderrBuf bytes.Buffer
+	parentPipe, childPipe, err := newPipe()
+	childStartPipe, parentStartPipe, err := newPipe()
+	if err != nil {
+		return fmt.Errorf("error creating socket pair: %v", err)
+	}
+	defer parentPipe.Close()
+	defer parentStartPipe.Close()
+
+	var args []string
+	if r.cgroupManager == SystemdCgroupsManager {
+		args = append(args, "-s")
+	}
+	args = append(args, "-c", c.id)
+	args = append(args, "-u", c.id)
+	args = append(args, "-r", r.Path(c))
+	args = append(args, "-b", c.bundlePath)
+	args = append(args, "-p", filepath.Join(c.bundlePath, "pidfile"))
+	args = append(args, "-l", c.logPath)
+	args = append(args, "--exit-dir", r.containerExitsDir)
+	args = append(args, "--socket-dir-path", ContainerAttachSocketDir)
+	if r.logSizeMax >= 0 {
+		args = append(args, "--log-size-max", fmt.Sprintf("%v", r.logSizeMax))
+	}
+	if r.noPivot {
+		args = append(args, "--no-pivot")
+	}
+	if c.terminal {
+		args = append(args, "-t")
+	} else if c.stdin {
+		args = append(args, "-i")
+	}
+	logrus.WithFields(logrus.Fields{
+		"args": args,
+	}).Debugf("running conmon: %s", r.conmonPath)
+
+	cmd := exec.Command(r.conmonPath, args...)
+	cmd.Dir = c.bundlePath
+	cmd.SysProcAttr = &syscall.SysProcAttr{
+		Setpgid: true,
+	}
+	cmd.Stdin = os.Stdin
+	cmd.Stdout = os.Stdout
+	cmd.Stderr = os.Stderr
+	if c.terminal {
+		cmd.Stderr = &stderrBuf
+	}
+	cmd.ExtraFiles = append(cmd.ExtraFiles, childPipe, childStartPipe)
+	// 0, 1 and 2 are stdin, stdout and stderr
+	cmd.Env = append(r.conmonEnv, fmt.Sprintf("_OCI_SYNCPIPE=%d", 3))
+	cmd.Env = append(cmd.Env, fmt.Sprintf("_OCI_STARTPIPE=%d", 4))
+
+	err = cmd.Start()
+	if err != nil {
+		childPipe.Close()
+		return err
+	}
+
+	// We don't need childPipe on the parent side
+	childPipe.Close()
+	childStartPipe.Close()
+
+	// Move conmon to specified cgroup
+	if r.cgroupManager == SystemdCgroupsManager {
+		logrus.Infof("Running conmon under slice %s and unitName %s", cgroupParent, createUnitName("crio-conmon", c.id))
+		if err = utils.RunUnderSystemdScope(cmd.Process.Pid, cgroupParent, createUnitName("crio-conmon", c.id)); err != nil {
+			logrus.Warnf("Failed to add conmon to systemd sandbox cgroup: %v", err)
+		}
+	} else {
+		control, err := cgroups.New(cgroups.V1, cgroups.StaticPath(filepath.Join(cgroupParent, "/crio-conmon-"+c.id)), &rspec.LinuxResources{})
+		if err != nil {
+			logrus.Warnf("Failed to add conmon to cgroupfs sandbox cgroup: %v", err)
+		} else {
+			// Here we should defer a crio-connmon- cgroup hierarchy deletion, but it will
+			// always fail as conmon's pid is still there.
+			// Fortunately, kubelet takes care of deleting this for us, so the leak will
+			// only happens in corner case where one does a manual deletion of the container
+			// through e.g. runc. This should be handled by implementing a conmon monitoring
+			// routine that does the cgroup cleanup once conmon is terminated.
+			if err := control.Add(cgroups.Process{Pid: cmd.Process.Pid}); err != nil {
+				logrus.Warnf("Failed to add conmon to cgroupfs sandbox cgroup: %v", err)
+			}
+		}
+	}
+
+	/* We set the cgroup, now the child can start creating children */
+	someData := []byte{0}
+	_, err = parentStartPipe.Write(someData)
+	if err != nil {
+		return err
+	}
+
+	/* Wait for initial setup and fork, and reap child */
+	err = cmd.Wait()
+	if err != nil {
+		return err
+	}
+
+	// We will delete all container resources if creation fails
+	defer func() {
+		if err != nil {
+			r.DeleteContainer(c)
+		}
+	}()
+
+	// Wait to get container pid from conmon
+	type syncStruct struct {
+		si  *syncInfo
+		err error
+	}
+	ch := make(chan syncStruct)
+	go func() {
+		var si *syncInfo
+		if err = json.NewDecoder(parentPipe).Decode(&si); err != nil {
+			ch <- syncStruct{err: err}
+			return
+		}
+		ch <- syncStruct{si: si}
+	}()
+
+	select {
+	case ss := <-ch:
+		if ss.err != nil {
+			return fmt.Errorf("error reading container (probably exited) json message: %v", ss.err)
+		}
+		logrus.Debugf("Received container pid: %d", ss.si.Pid)
+		if ss.si.Pid == -1 {
+			if ss.si.Message != "" {
+				logrus.Errorf("Container creation error: %s", ss.si.Message)
+				return fmt.Errorf("container create failed: %s", ss.si.Message)
+			}
+			logrus.Errorf("Container creation failed")
+			return fmt.Errorf("container create failed")
+		}
+	case <-time.After(ContainerCreateTimeout):
+		logrus.Errorf("Container creation timeout (%v)", ContainerCreateTimeout)
+		return fmt.Errorf("create container timeout")
+	}
+	return nil
+}
+
+func createUnitName(prefix string, name string) string {
+	return fmt.Sprintf("%s-%s.scope", prefix, name)
+}
+
+// StartContainer starts a container.
+func (r *Runtime) StartContainer(c *Container) error {
+	c.opLock.Lock()
+	defer c.opLock.Unlock()
+	if err := utils.ExecCmdWithStdStreams(os.Stdin, os.Stdout, os.Stderr, r.Path(c), "start", c.id); err != nil {
+		return err
+	}
+	c.state.Started = time.Now()
+	return nil
+}
+
+// ExecSyncResponse is returned from ExecSync.
+type ExecSyncResponse struct {
+	Stdout   []byte
+	Stderr   []byte
+	ExitCode int32
+}
+
+// ExecSyncError wraps command's streams, exit code and error on ExecSync error.
+type ExecSyncError struct {
+	Stdout   bytes.Buffer
+	Stderr   bytes.Buffer
+	ExitCode int32
+	Err      error
+}
+
+func (e ExecSyncError) Error() string {
+	return fmt.Sprintf("command error: %+v, stdout: %s, stderr: %s, exit code %d", e.Err, e.Stdout.Bytes(), e.Stderr.Bytes(), e.ExitCode)
+}
+
+func prepareExec() (pidFile, parentPipe, childPipe *os.File, err error) {
+	parentPipe, childPipe, err = os.Pipe()
+	if err != nil {
+		return nil, nil, nil, err
+	}
+
+	pidFile, err = ioutil.TempFile("", "pidfile")
+	if err != nil {
+		parentPipe.Close()
+		childPipe.Close()
+		return nil, nil, nil, err
+	}
+
+	return
+}
+
+func parseLog(log []byte) (stdout, stderr []byte) {
+	// Split the log on newlines, which is what separates entries.
+	lines := bytes.SplitAfter(log, []byte{'\n'})
+	for _, line := range lines {
+		// Ignore empty lines.
+		if len(line) == 0 {
+			continue
+		}
+
+		// The format of log lines is "DATE pipe REST".
+		parts := bytes.SplitN(line, []byte{' '}, 3)
+		if len(parts) < 3 {
+			// Ignore the line if it's formatted incorrectly, but complain
+			// about it so it can be debugged.
+			logrus.Warnf("hit invalid log format: %q", string(line))
+			continue
+		}
+
+		pipe := string(parts[1])
+		content := parts[2]
+
+		switch pipe {
+		case "stdout":
+			stdout = append(stdout, content...)
+		case "stderr":
+			stderr = append(stderr, content...)
+		default:
+			// Complain about unknown pipes.
+			logrus.Warnf("hit invalid log format [unknown pipe %s]: %q", pipe, string(line))
+			continue
+		}
+	}
+
+	return stdout, stderr
+}
+
+// ExecSync execs a command in a container and returns it's stdout, stderr and return code.
+func (r *Runtime) ExecSync(c *Container, command []string, timeout int64) (resp *ExecSyncResponse, err error) {
+	pidFile, parentPipe, childPipe, err := prepareExec()
+	if err != nil {
+		return nil, ExecSyncError{
+			ExitCode: -1,
+			Err:      err,
+		}
+	}
+	defer parentPipe.Close()
+	defer func() {
+		if e := os.Remove(pidFile.Name()); e != nil {
+			logrus.Warnf("could not remove temporary PID file %s", pidFile.Name())
+		}
+	}()
+
+	logFile, err := ioutil.TempFile("", "crio-log-"+c.id)
+	if err != nil {
+		return nil, ExecSyncError{
+			ExitCode: -1,
+			Err:      err,
+		}
+	}
+	logPath := logFile.Name()
+	defer func() {
+		logFile.Close()
+		os.RemoveAll(logPath)
+	}()
+
+	f, err := ioutil.TempFile("", "exec-process")
+	if err != nil {
+		return nil, ExecSyncError{
+			ExitCode: -1,
+			Err:      err,
+		}
+	}
+	defer os.RemoveAll(f.Name())
+
+	var args []string
+	args = append(args, "-c", c.id)
+	args = append(args, "-r", r.Path(c))
+	args = append(args, "-p", pidFile.Name())
+	args = append(args, "-e")
+	if c.terminal {
+		args = append(args, "-t")
+	}
+	if timeout > 0 {
+		args = append(args, "-T")
+		args = append(args, fmt.Sprintf("%d", timeout))
+	}
+	args = append(args, "-l", logPath)
+	args = append(args, "--socket-dir-path", ContainerAttachSocketDir)
+
+	pspec := c.Spec().Process
+	pspec.Env = append(pspec.Env, r.conmonEnv...)
+	pspec.Args = command
+	processJSON, err := json.Marshal(pspec)
+	if err != nil {
+		return nil, ExecSyncError{
+			ExitCode: -1,
+			Err:      err,
+		}
+	}
+
+	if err := ioutil.WriteFile(f.Name(), processJSON, 0644); err != nil {
+		return nil, ExecSyncError{
+			ExitCode: -1,
+			Err:      err,
+		}
+	}
+
+	args = append(args, "--exec-process-spec", f.Name())
+
+	cmd := exec.Command(r.conmonPath, args...)
+
+	var stdoutBuf, stderrBuf bytes.Buffer
+	cmd.Stdout = &stdoutBuf
+	cmd.Stderr = &stderrBuf
+	cmd.ExtraFiles = append(cmd.ExtraFiles, childPipe)
+	// 0, 1 and 2 are stdin, stdout and stderr
+	cmd.Env = append(r.conmonEnv, fmt.Sprintf("_OCI_SYNCPIPE=%d", 3))
+
+	err = cmd.Start()
+	if err != nil {
+		childPipe.Close()
+		return nil, ExecSyncError{
+			Stdout:   stdoutBuf,
+			Stderr:   stderrBuf,
+			ExitCode: -1,
+			Err:      err,
+		}
+	}
+
+	// We don't need childPipe on the parent side
+	childPipe.Close()
+
+	err = cmd.Wait()
+	if err != nil {
+		if exitErr, ok := err.(*exec.ExitError); ok {
+			if status, ok := exitErr.Sys().(unix.WaitStatus); ok {
+				return nil, ExecSyncError{
+					Stdout:   stdoutBuf,
+					Stderr:   stderrBuf,
+					ExitCode: int32(status.ExitStatus()),
+					Err:      err,
+				}
+			}
+		} else {
+			return nil, ExecSyncError{
+				Stdout:   stdoutBuf,
+				Stderr:   stderrBuf,
+				ExitCode: -1,
+				Err:      err,
+			}
+		}
+	}
+
+	var ec *exitCodeInfo
+	if err := json.NewDecoder(parentPipe).Decode(&ec); err != nil {
+		return nil, ExecSyncError{
+			Stdout:   stdoutBuf,
+			Stderr:   stderrBuf,
+			ExitCode: -1,
+			Err:      err,
+		}
+	}
+
+	logrus.Infof("Received container exit code: %v, message: %s", ec.ExitCode, ec.Message)
+
+	if ec.ExitCode == -1 {
+		return nil, ExecSyncError{
+			Stdout:   stdoutBuf,
+			Stderr:   stderrBuf,
+			ExitCode: -1,
+			Err:      fmt.Errorf(ec.Message),
+		}
+	}
+
+	// The actual logged output is not the same as stdoutBuf and stderrBuf,
+	// which are used for getting error information. For the actual
+	// ExecSyncResponse we have to read the logfile.
+	// XXX: Currently runC dups the same console over both stdout and stderr,
+	//      so we can't differentiate between the two.
+
+	logBytes, err := ioutil.ReadFile(logPath)
+	if err != nil {
+		return nil, ExecSyncError{
+			Stdout:   stdoutBuf,
+			Stderr:   stderrBuf,
+			ExitCode: -1,
+			Err:      err,
+		}
+	}
+
+	// We have to parse the log output into {stdout, stderr} buffers.
+	stdoutBytes, stderrBytes := parseLog(logBytes)
+	return &ExecSyncResponse{
+		Stdout:   stdoutBytes,
+		Stderr:   stderrBytes,
+		ExitCode: ec.ExitCode,
+	}, nil
+}
+
+func waitContainerStop(ctx context.Context, c *Container, timeout time.Duration) error {
+	done := make(chan struct{})
+	// we could potentially re-use "done" channel to exit the loop on timeout
+	// but we use another channel "chControl" so that we won't never incur in the
+	// case the "done" channel is closed in the "default" select case and we also
+	// reach the timeout in the select below. If that happens we could raise
+	// a panic closing a closed channel so better be safe and use another new
+	// channel just to control the loop.
+	chControl := make(chan struct{})
+	go func() {
+		for {
+			select {
+			case <-chControl:
+				return
+			default:
+				// Check if the process is still around
+				err := unix.Kill(c.state.Pid, 0)
+				if err == unix.ESRCH {
+					close(done)
+					return
+				}
+				time.Sleep(100 * time.Millisecond)
+			}
+		}
+	}()
+	select {
+	case <-done:
+		return nil
+	case <-ctx.Done():
+		close(chControl)
+		return ctx.Err()
+	case <-time.After(timeout):
+		close(chControl)
+		err := unix.Kill(c.state.Pid, unix.SIGKILL)
+		if err != nil && err != unix.ESRCH {
+			return fmt.Errorf("failed to kill process: %v", err)
+		}
+	}
+
+	c.state.Finished = time.Now()
+	return nil
+}
+
+// StopContainer stops a container. Timeout is given in seconds.
+func (r *Runtime) StopContainer(ctx context.Context, c *Container, timeout int64) error {
+	c.opLock.Lock()
+	defer c.opLock.Unlock()
+
+	// Check if the process is around before sending a signal
+	err := unix.Kill(c.state.Pid, 0)
+	if err == unix.ESRCH {
+		c.state.Finished = time.Now()
+		return nil
+	}
+
+	if timeout > 0 {
+		if err := utils.ExecCmdWithStdStreams(os.Stdin, os.Stdout, os.Stderr, r.Path(c), "kill", c.id, c.GetStopSignal()); err != nil {
+			return fmt.Errorf("failed to stop container %s, %v", c.id, err)
+		}
+		err = waitContainerStop(ctx, c, time.Duration(timeout)*time.Second)
+		if err == nil {
+			return nil
+		}
+		logrus.Warnf("Stop container %q timed out: %v", c.ID(), err)
+	}
+
+	if err := utils.ExecCmdWithStdStreams(os.Stdin, os.Stdout, os.Stderr, r.Path(c), "kill", "--all", c.id, "KILL"); err != nil {
+		return fmt.Errorf("failed to stop container %s, %v", c.id, err)
+	}
+
+	return waitContainerStop(ctx, c, killContainerTimeout)
+}
+
+// DeleteContainer deletes a container.
+func (r *Runtime) DeleteContainer(c *Container) error {
+	c.opLock.Lock()
+	defer c.opLock.Unlock()
+	_, err := utils.ExecCmd(r.Path(c), "delete", "--force", c.id)
+	return err
+}
+
+// SetStartFailed sets the container state appropriately after a start failure
+func (r *Runtime) SetStartFailed(c *Container, err error) {
+	c.opLock.Lock()
+	defer c.opLock.Unlock()
+	// adjust finished and started times
+	c.state.Finished, c.state.Started = c.state.Created, c.state.Created
+	c.state.Error = err.Error()
+}
+
+// UpdateStatus refreshes the status of the container.
+func (r *Runtime) UpdateStatus(c *Container) error {
+	c.opLock.Lock()
+	defer c.opLock.Unlock()
+	out, err := exec.Command(r.Path(c), "state", c.id).CombinedOutput()
+	if err != nil {
+		// there are many code paths that could lead to have a bad state in the
+		// underlying runtime.
+		// On any error like a container went away or we rebooted and containers
+		// went away we do not error out stopping kubernetes to recover.
+		// We always populate the fields below so kube can restart/reschedule
+		// containers failing.
+		c.state.Status = ContainerStateStopped
+		c.state.Finished = time.Now()
+		c.state.ExitCode = 255
+		return nil
+	}
+	if err := json.NewDecoder(bytes.NewBuffer(out)).Decode(&c.state); err != nil {
+		return fmt.Errorf("failed to decode container status for %s: %s", c.id, err)
+	}
+
+	if c.state.Status == ContainerStateStopped {
+		exitFilePath := filepath.Join(r.containerExitsDir, c.id)
+		var fi os.FileInfo
+		err = kwait.ExponentialBackoff(
+			kwait.Backoff{
+				Duration: 500 * time.Millisecond,
+				Factor:   1.2,
+				Steps:    6,
+			},
+			func() (bool, error) {
+				var err error
+				fi, err = os.Stat(exitFilePath)
+				if err != nil {
+					// wait longer
+					return false, nil
+				}
+				return true, nil
+			})
+		if err != nil {
+			logrus.Warnf("failed to find container exit file: %v", err)
+			c.state.ExitCode = -1
+		} else {
+			c.state.Finished = getFinishedTime(fi)
+			statusCodeStr, err := ioutil.ReadFile(exitFilePath)
+			if err != nil {
+				return fmt.Errorf("failed to read exit file: %v", err)
+			}
+			statusCode, err := strconv.Atoi(string(statusCodeStr))
+			if err != nil {
+				return fmt.Errorf("status code conversion failed: %v", err)
+			}
+			c.state.ExitCode = int32(statusCode)
+		}
+
+		oomFilePath := filepath.Join(c.bundlePath, "oom")
+		if _, err = os.Stat(oomFilePath); err == nil {
+			c.state.OOMKilled = true
+		}
+	}
+
+	return nil
+}
+
+// ContainerStatus returns the state of a container.
+func (r *Runtime) ContainerStatus(c *Container) *ContainerState {
+	c.opLock.Lock()
+	defer c.opLock.Unlock()
+	return c.state
+}
+
+// newPipe creates a unix socket pair for communication
+func newPipe() (parent *os.File, child *os.File, err error) {
+	fds, err := unix.Socketpair(unix.AF_LOCAL, unix.SOCK_STREAM|unix.SOCK_CLOEXEC, 0)
+	if err != nil {
+		return nil, nil, err
+	}
+	return os.NewFile(uintptr(fds[1]), "parent"), os.NewFile(uintptr(fds[0]), "child"), nil
+}
+
+// RuntimeReady checks if the runtime is up and ready to accept
+// basic containers e.g. container only needs host network.
+func (r *Runtime) RuntimeReady() (bool, error) {
+	return true, nil
+}
+
+// NetworkReady checks if the runtime network is up and ready to
+// accept containers which require container network.
+func (r *Runtime) NetworkReady() (bool, error) {
+	return true, nil
+}
+
+// PauseContainer pauses a container.
+func (r *Runtime) PauseContainer(c *Container) error {
+	c.opLock.Lock()
+	defer c.opLock.Unlock()
+	_, err := utils.ExecCmd(r.Path(c), "pause", c.id)
+	return err
+}
+
+// UnpauseContainer unpauses a container.
+func (r *Runtime) UnpauseContainer(c *Container) error {
+	c.opLock.Lock()
+	defer c.opLock.Unlock()
+	_, err := utils.ExecCmd(r.Path(c), "resume", c.id)
+	return err
+}