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// +build linux
package main
import (
"fmt"
"strconv"
"strings"
"syscall"
"github.com/opencontainers/runc/libcontainer"
"github.com/opencontainers/runtime-spec/specs-go"
"github.com/urfave/cli"
)
var checkpointCommand = cli.Command{
Name: "checkpoint",
Usage: "checkpoint a running container",
ArgsUsage: `<container-id>
Where "<container-id>" is the name for the instance of the container to be
checkpointed.`,
Description: `The checkpoint command saves the state of the container instance.`,
Flags: []cli.Flag{
cli.StringFlag{Name: "image-path", Value: "", Usage: "path for saving criu image files"},
cli.StringFlag{Name: "work-path", Value: "", Usage: "path for saving work files and logs"},
cli.BoolFlag{Name: "leave-running", Usage: "leave the process running after checkpointing"},
cli.BoolFlag{Name: "tcp-established", Usage: "allow open tcp connections"},
cli.BoolFlag{Name: "ext-unix-sk", Usage: "allow external unix sockets"},
cli.BoolFlag{Name: "shell-job", Usage: "allow shell jobs"},
cli.StringFlag{Name: "page-server", Value: "", Usage: "ADDRESS:PORT of the page server"},
cli.BoolFlag{Name: "file-locks", Usage: "handle file locks, for safety"},
cli.StringFlag{Name: "manage-cgroups-mode", Value: "", Usage: "cgroups mode: 'soft' (default), 'full' and 'strict'"},
cli.StringSliceFlag{Name: "empty-ns", Usage: "create a namespace, but don't restore its properies"},
},
Action: func(context *cli.Context) error {
if err := checkArgs(context, 1, exactArgs); err != nil {
return err
}
container, err := getContainer(context)
if err != nil {
return err
}
status, err := container.Status()
if err != nil {
return err
}
if status == libcontainer.Created {
fatalf("Container cannot be checkpointed in created state")
}
defer destroy(container)
options := criuOptions(context)
// these are the mandatory criu options for a container
setPageServer(context, options)
setManageCgroupsMode(context, options)
if err := setEmptyNsMask(context, options); err != nil {
return err
}
if err := container.Checkpoint(options); err != nil {
return err
}
return nil
},
}
func getCheckpointImagePath(context *cli.Context) string {
imagePath := context.String("image-path")
if imagePath == "" {
imagePath = getDefaultImagePath(context)
}
return imagePath
}
func setPageServer(context *cli.Context, options *libcontainer.CriuOpts) {
// xxx following criu opts are optional
// The dump image can be sent to a criu page server
if psOpt := context.String("page-server"); psOpt != "" {
addressPort := strings.Split(psOpt, ":")
if len(addressPort) != 2 {
fatal(fmt.Errorf("Use --page-server ADDRESS:PORT to specify page server"))
}
portInt, err := strconv.Atoi(addressPort[1])
if err != nil {
fatal(fmt.Errorf("Invalid port number"))
}
options.PageServer = libcontainer.CriuPageServerInfo{
Address: addressPort[0],
Port: int32(portInt),
}
}
}
func setManageCgroupsMode(context *cli.Context, options *libcontainer.CriuOpts) {
if cgOpt := context.String("manage-cgroups-mode"); cgOpt != "" {
switch cgOpt {
case "soft":
options.ManageCgroupsMode = libcontainer.CRIU_CG_MODE_SOFT
case "full":
options.ManageCgroupsMode = libcontainer.CRIU_CG_MODE_FULL
case "strict":
options.ManageCgroupsMode = libcontainer.CRIU_CG_MODE_STRICT
default:
fatal(fmt.Errorf("Invalid manage cgroups mode"))
}
}
}
var namespaceMapping = map[specs.LinuxNamespaceType]int{
specs.NetworkNamespace: syscall.CLONE_NEWNET,
}
func setEmptyNsMask(context *cli.Context, options *libcontainer.CriuOpts) error {
var nsmask int
for _, ns := range context.StringSlice("empty-ns") {
f, exists := namespaceMapping[specs.LinuxNamespaceType(ns)]
if !exists {
return fmt.Errorf("namespace %q is not supported", ns)
}
nsmask |= f
}
options.EmptyNs = uint32(nsmask)
return nil
}