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mirror of https://github.com/rancher/os.git synced 2025-07-07 11:58:38 +00:00

Use Docker exec to start User Docker

This commit is contained in:
Josh Curl 2016-05-16 15:29:42 -07:00
parent 42e48476e7
commit b2ab4d0c38
2 changed files with 85 additions and 151 deletions

View File

@ -1,32 +1,29 @@
package userdocker
import (
"bufio"
"encoding/json"
"fmt"
"io/ioutil"
"os"
"os/exec"
"os/signal"
"strings"
"strconv"
"syscall"
"time"
"golang.org/x/net/context"
log "github.com/Sirupsen/logrus"
"github.com/docker/engine-api/types"
composeClient "github.com/docker/libcompose/docker/client"
"github.com/docker/libcompose/project"
"github.com/rancher/os/cmd/control"
"github.com/rancher/os/compose"
"github.com/rancher/os/config"
"github.com/opencontainers/runc/libcontainer/cgroups"
_ "github.com/opencontainers/runc/libcontainer/nsenter"
"github.com/opencontainers/runc/libcontainer/system"
rosDocker "github.com/rancher/os/docker"
)
const (
DEFAULT_STORAGE_CONTEXT = "console"
DOCKER_PID_FILE = "/var/run/docker.pid"
DOCKER_COMMAND = "docker-init"
userDocker = "user-docker"
)
@ -36,109 +33,102 @@ func Main() {
log.Fatal(err)
}
if len(os.Args) == 1 {
if err := enter(cfg); err != nil {
log.Fatal(err)
}
} else {
if err := main(cfg); err != nil {
log.Fatal(err)
}
if err := startDocker(cfg); err != nil {
log.Fatal(err)
}
if err := setupTermHandler(); err != nil {
log.Fatal(err)
}
select {}
}
func enter(cfg *config.CloudConfig) error {
context := cfg.Rancher.Docker.StorageContext
if context == "" {
context = DEFAULT_STORAGE_CONTEXT
func startDocker(cfg *config.CloudConfig) error {
storageContext := cfg.Rancher.Docker.StorageContext
if storageContext == "" {
storageContext = DEFAULT_STORAGE_CONTEXT
}
log.Infof("Starting Docker in context: %s", context)
log.Infof("Starting Docker in context: %s", storageContext)
p, err := compose.GetProject(cfg, true)
if err != nil {
return err
}
pid, err := waitForPid(context, p)
pid, err := waitForPid(storageContext, p)
if err != nil {
return err
}
log.Infof("%s PID %d", context, pid)
log.Infof("%s PID %d", storageContext, pid)
return runNsenter(pid)
}
client, err := rosDocker.NewSystemClient()
if err != nil {
return err
}
type result struct {
Pid int `json:"Pid"`
}
if err := os.Remove(DOCKER_PID_FILE); err != nil && !os.IsNotExist(err) {
return err
}
func findProgram(searchPaths ...string) string {
prog := ""
dockerCfg := cfg.Rancher.Docker
for _, i := range searchPaths {
var err error
prog, err = exec.LookPath(i)
if err == nil {
break
args := dockerCfg.FullArgs()
log.Debugf("User Docker args: %v", args)
if dockerCfg.TLS {
log.Debug("Generating TLS certs if needed")
if err := control.Generate(true, "/etc/docker/tls", []string{"127.0.0.1", "*", "*.*", "*.*.*", "*.*.*.*"}); err != nil {
return err
}
prog = i
}
return prog
cmd := []string{"env"}
log.Info(dockerCfg.AppendEnv())
cmd = append(cmd, dockerCfg.AppendEnv()...)
cmd = append(cmd, DOCKER_COMMAND)
cmd = append(cmd, args...)
log.Infof("Running %v", cmd)
resp, err := client.ContainerExecCreate(context.Background(), storageContext, types.ExecConfig{
Privileged: true,
AttachStdin: true,
AttachStderr: true,
AttachStdout: true,
Detach: false,
Cmd: cmd,
})
if err != nil {
return err
}
if err := client.ContainerExecStart(context.Background(), resp.ID, types.ExecStartCheck{
Detach: false,
}); err != nil {
return err
}
return nil
}
func runNsenter(pid int) error {
args := []string{findProgram(userDocker), "main"}
r, w, err := os.Pipe()
func setupTermHandler() error {
pidBytes, err := waitForFile(DOCKER_PID_FILE)
if err != nil {
return err
}
cmd := &exec.Cmd{
Path: args[0],
Args: args,
Stdin: os.Stdin,
Stdout: os.Stdout,
Stderr: os.Stderr,
ExtraFiles: []*os.File{w},
Env: append(os.Environ(),
"_LIBCONTAINER_INITPIPE=3",
fmt.Sprintf("_LIBCONTAINER_INITPID=%d", pid),
),
}
if err := cmd.Start(); err != nil {
return err
}
w.Close()
var result result
if err := json.NewDecoder(r).Decode(&result); err != nil {
return err
}
if err := cmd.Wait(); err != nil {
return err
}
log.Infof("Docker PID %d", result.Pid)
p, err := os.FindProcess(result.Pid)
dockerPid, err := strconv.Atoi(string(pidBytes))
if err != nil {
return err
}
handleTerm(p)
if err := switchCgroup(result.Pid, pid); err != nil {
process, err := os.FindProcess(dockerPid)
if err != nil {
return err
}
_, err = p.Wait()
return err
handleTerm(process)
return nil
}
func handleTerm(p *os.Process) {
@ -147,9 +137,24 @@ func handleTerm(p *os.Process) {
go func() {
<-term
p.Signal(syscall.SIGTERM)
os.Exit(0)
}()
}
func waitForFile(file string) ([]byte, error) {
for {
contents, err := ioutil.ReadFile(file)
if os.IsNotExist(err) {
log.Infof("Waiting for %s", file)
time.Sleep(1 * time.Second)
} else if err != nil {
return nil, err
} else {
return contents, nil
}
}
}
func waitForPid(service string, project *project.Project) (int, error) {
log.Infof("Getting PID for service: %s", service)
for {
@ -200,71 +205,3 @@ func getPid(service string, project *project.Project) (int, error) {
return 0, nil
}
func main(cfg *config.CloudConfig) error {
os.Unsetenv("_LIBCONTAINER_INITPIPE")
os.Unsetenv("_LIBCONTAINER_INITPID")
if err := system.ParentDeathSignal(syscall.SIGKILL).Set(); err != nil {
return err
}
if err := os.Remove("/var/run/docker.pid"); err != nil && !os.IsNotExist(err) {
return err
}
dockerCfg := cfg.Rancher.Docker
args := dockerCfg.FullArgs()
log.Debugf("User Docker args: %v", args)
if dockerCfg.TLS {
log.Debug("Generating TLS certs if needed")
if err := control.Generate(true, "/etc/docker/tls", []string{"127.0.0.1", "*", "*.*", "*.*.*", "*.*.*.*"}); err != nil {
return err
}
}
prog := findProgram("docker-init", "dockerlaunch", "docker")
if strings.Contains(prog, "dockerlaunch") {
args = append([]string{prog, "docker"}, args...)
} else {
args = append([]string{prog}, args...)
}
log.Infof("Running %v", args)
return syscall.Exec(args[0], args, dockerCfg.AppendEnv())
}
func switchCgroup(src, target int) error {
cgroupFile := fmt.Sprintf("/proc/%d/cgroup", target)
f, err := os.Open(cgroupFile)
if err != nil {
return err
}
defer f.Close()
targetCgroups := map[string]string{}
s := bufio.NewScanner(f)
for s.Scan() {
text := s.Text()
parts := strings.Split(text, ":")
subparts := strings.Split(parts[1], "=")
subsystem := subparts[0]
if len(subparts) > 1 {
subsystem = subparts[1]
}
targetPath := fmt.Sprintf("/host/sys/fs/cgroup/%s%s", subsystem, parts[2])
log.Infof("Moving Docker to cgroup %s", targetPath)
targetCgroups[subsystem] = targetPath
}
if err := s.Err(); err != nil {
return err
}
return cgroups.EnterPid(targetCgroups, src)
}

View File

@ -107,9 +107,6 @@ func (s *Service) shouldRebuild(ctx context.Context) (bool, error) {
rebuilding := false
if outOfSync {
if s.Name() != "console" {
continue
}
if cfg.Rancher.ForceConsoleRebuild && s.Name() == "console" {
cfg.Rancher.ForceConsoleRebuild = false
if err := cfg.Save(); err != nil {