Add nsinit support for checkpoint and restore

Signed-off-by: Michael Crosby <crosbymichael@gmail.com>

container_linux.go

@@ -110,7 +110,6 @@ func (c *linuxContainer) Start(process *Process) error {
 	}
 	process.ops = parent
 	if doInit {
-
 		c.updateState(parent)
 	}
 	return nil
@@ -257,9 +256,13 @@ func (c *linuxContainer) NotifyOOM() (<-chan struct{}, error) {
 }
 
 func (c *linuxContainer) Checkpoint() error {
+	dir := filepath.Join(c.root, "checkpoint")
+	if err := os.Mkdir(dir, 0655); err != nil {
+		return err
+	}
 	args := []string{
 		"dump", "-v4",
-		"-D", filepath.Join(c.root, "checkpoint"),
+		"-D", dir,
 		"-o", "dump.log",
 		"--root", c.config.Rootfs,
 		"--manage-cgroups", "--evasive-devices",

nsinit/checkpoint.go

@@ -0,0 +1,20 @@
+package main
+
+import "github.com/codegangsta/cli"
+
+var checkpointCommand = cli.Command{
+	Name:  "checkpoint",
+	Usage: "checkpoint a running container",
+	Flags: []cli.Flag{
+		cli.StringFlag{Name: "id", Value: "nsinit", Usage: "specify the ID for a container"},
+	},
+	Action: func(context *cli.Context) {
+		container, err := getContainer(context)
+		if err != nil {
+			fatal(err)
+		}
+		if err := container.Checkpoint(); err != nil {
+			fatal(err)
+		}
+	},
+}

nsinit/main.go

@@ -13,19 +13,22 @@ func main() {
 	app.Version = "2"
 	app.Author = "libcontainer maintainers"
 	app.Flags = []cli.Flag{
-		cli.StringFlag{Name: "root", Value: "/var/run/nsinit", Usage: "root directory for containers"},
-		cli.StringFlag{Name: "log-file", Value: "", Usage: "set the log file to output logs to"},
 		cli.BoolFlag{Name: "debug", Usage: "enable debug output in the logs"},
+		cli.StringFlag{Name: "root", Value: "/var/run/nsinit", Usage: "root directory for containers"},
+		cli.StringFlag{Name: "log-file", Usage: "set the log file to output logs to"},
+		cli.StringFlag{Name: "criu", Usage: "path to the criu binary for checkpoint and restore"},
 	}
 	app.Commands = []cli.Command{
+		checkpointCommand,
 		configCommand,
 		execCommand,
 		initCommand,
 		oomCommand,
 		pauseCommand,
+		stateCommand,
 		statsCommand,
 		unpauseCommand,
-		stateCommand,
+		restoreCommand,
 	}
 	app.Before = func(context *cli.Context) error {
 		if context.GlobalBool("debug") {

nsinit/restore.go

@@ -0,0 +1,20 @@
+package main
+
+import "github.com/codegangsta/cli"
+
+var restoreCommand = cli.Command{
+	Name:  "restore",
+	Usage: "restore a container from a previous checkpoint",
+	Flags: []cli.Flag{
+		cli.StringFlag{Name: "id", Value: "nsinit", Usage: "specify the ID for a container"},
+	},
+	Action: func(context *cli.Context) {
+		container, err := getContainer(context)
+		if err != nil {
+			fatal(err)
+		}
+		if err := container.Restore(); err != nil {
+			fatal(err)
+		}
+	},
+}

nsinit/utils.go

@@ -3,9 +3,10 @@ package main
 import (
 	"encoding/json"
 	"fmt"
-	"github.com/Sirupsen/logrus"
 	"os"
 
+	"github.com/Sirupsen/logrus"
+
 	"github.com/codegangsta/cli"
 	"github.com/docker/libcontainer"
 	"github.com/docker/libcontainer/cgroups/systemd"
@@ -39,7 +40,10 @@ func loadFactory(context *cli.Context) (libcontainer.Factory, error) {
 			logrus.Warn("systemd cgroup flag passed, but systemd support for managing cgroups is not available.")
 		}
 	}
-	return libcontainer.New(context.GlobalString("root"), cgm)
+	return libcontainer.New(context.GlobalString("root"), cgm, func(l *libcontainer.LinuxFactory) error {
+		l.CriuPath = context.GlobalString("criu")
+		return nil
+	})
 }
 
 func getContainer(context *cli.Context) (libcontainer.Container, error) {