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containerd
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Finish port of shim package 

Signed-off-by: Michael Crosby <crosbymichael@gmail.com>
This commit is contained in:
Michael Crosby 2016-10-05 15:07:20 -07:00
parent 0f33efb1f7
commit c76f883ccd
5 changed files with 424 additions and 90 deletions
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5
container.go
View File

@ -126,6 +126,11 @@ func (c *Container) Path() string {
return c.path
}
// Spec returns the OCI runtime spec for the container
func (c *Container) Spec() *specs.Spec {
return c.s
}
// Create will create the container on the system by running the runtime's
// initial setup and process waiting for the user process to be started
func (c *Container) Create() error {

6
containerd-shim/main.go
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@ -139,6 +139,7 @@ func start(log *os.File) error {
p.stdinCloser.Close()
}
case 1:
// resize
if p.console == nil {
continue
}
@ -147,6 +148,11 @@ func start(log *os.File) error {
Height: uint16(msg.Height),
}
term.SetWinsize(p.console.Fd(), &ws)
case 2:
// signal
if err := syscall.Kill(p.pid(), msg.Width); err != nil {
writeMessage(log, "warn", err)
}
}
}
}

10
oci/oci.go
View File

@ -2,6 +2,7 @@ package oci
import (
"encoding/json"
"errors"
"fmt"
"io/ioutil"
"os"
@ -13,6 +14,8 @@ import (
"github.com/docker/containerkit"
)
var ErrRootEmpty = errors.New("oci: runtime root cannot be an empty string")
type Opts struct {
Name string
Root string
@ -20,6 +23,9 @@ type Opts struct {
}
func New(opts Opts) (*OCIRuntime, error) {
if opts.Root == "" {
return nil, ErrRootEmpty
}
if err := os.MkdirAll(opts.Root, 0711); err != nil {
return nil, err
}
@ -44,6 +50,10 @@ func (r *OCIRuntime) Name() string {
return r.name
}
func (r *OCIRuntime) Args() []string {
return r.args
}
func (r *OCIRuntime) Create(c *containerkit.Container) (containerkit.ProcessDelegate, error) {
pidFile := fmt.Sprintf("%s/%s.pid", filepath.Join(r.root, c.ID()), "init")
cmd := r.Command("create", "--pid-file", pidFile, "--bundle", c.Path(), c.ID())

264
shim/process.go
View File

@ -1,4 +1,4 @@
package process
package shim
import (
"encoding/json"
@ -16,13 +16,90 @@ import (
"time"
"github.com/Sirupsen/logrus"
"github.com/docker/containerkit"
specs "github.com/opencontainers/runtime-spec/specs-go"
"golang.org/x/sys/unix"
)
var errInvalidPidInt = errors.New("containerd: process pid is invalid")
var (
ErrContainerStartTimeout = errors.New("shim: container did not start before the specified timeout")
ErrContainerNotStarted = errors.New("shim: container not started")
ErrProcessNotExited = errors.New("containerd: process has not exited")
ErrShimExited = errors.New("containerd: shim exited before container process was started")
errInvalidPidInt = errors.New("shim: process pid is invalid")
)
const UnknownStatus = 255
func newProcess(root string, noPivotRoot bool, checkpoint string, c *containerkit.Container, cmd *exec.Cmd) (*process, error) {
var (
spec = c.Spec()
stdin, stdout, stderr string
)
uid, gid, err := getRootIDs(spec)
if err != nil {
return nil, err
}
for _, t := range []struct {
path *string
v interface{}
}{
{
path: &stdin,
v: c.Stdin,
},
{
path: &stdout,
v: c.Stdout,
},
{
path: &stderr,
v: c.Stderr,
},
} {
p, err := getFifoPath(t.v)
if err != nil {
return nil, err
}
*t.path = p
}
p := &process{
root: root,
cmd: cmd,
done: make(chan struct{}),
spec: spec.Process,
exec: false,
rootUid: uid,
rootGid: gid,
noPivotRoot: noPivotRoot,
checkpoint: checkpoint,
stdin: stdin,
stdout: stdout,
stderr: stderr,
}
f, err := os.Create(filepath.Join(root, "process.json"))
if err != nil {
return nil, err
}
err = json.NewEncoder(f).Encode(p)
f.Close()
if err != nil {
return nil, err
}
exit, err := getExitPipe(filepath.Join(root, "exit"))
if err != nil {
return nil, err
}
control, err := getControlPipe(filepath.Join(root, "control"))
if err != nil {
return nil, err
}
p.exit, p.control = exit, control
return p, nil
}
// TODO: control and exit fifo
type process struct {
name string
root string
cmd *exec.Cmd
done chan struct{}
@ -30,7 +107,100 @@ type process struct {
startTime string
mu sync.Mutex
containerPid int
timeout time.Duration
exit *os.File
control *os.File
spec specs.Process
noPivotRoot bool
exec bool
rootUid int
rootGid int
checkpoint string
stdin string
stdout string
stderr string
}
type processState struct {
specs.Process
Exec bool `json:"exec"`
RootUID int `json:"rootUID"`
RootGID int `json:"rootGID"`
Checkpoint string `json:"checkpoint"`
NoPivotRoot bool `json:"noPivotRoot"`
RuntimeArgs []string `json:"runtimeArgs"`
// Stdin fifo filepath
Stdin string `json:"stdin"`
// Stdout fifo filepath
Stdout string `json:"stdout"`
// Stderr fifo filepath
Stderr string `json:"stderr"`
}
func (p *process) MarshalJSON() ([]byte, error) {
ps := processState{
Process: p.spec,
NoPivotRoot: p.noPivotRoot,
Checkpoint: p.checkpoint,
RootUID: p.rootUid,
RootGID: p.rootGid,
Exec: p.exec,
Stdin: p.stdin,
Stdout: p.stdout,
Stderr: p.stderr,
}
return json.Marshal(ps)
}
func (p *process) UnmarshalJSON(b []byte) error {
var ps processState
if err := json.Unmarshal(b, &ps); err != nil {
return err
}
p.spec = ps.Process
p.noPivotRoot = ps.NoPivotRoot
p.rootGid = ps.RootGID
p.rootUid = ps.RootUID
p.checkpoint = ps.Checkpoint
p.exec = ps.Exec
p.stdin = ps.Stdin
p.stdout = ps.Stdout
p.stderr = ps.Stderr
// TODO: restore pid/exit/control and stuff ?
return nil
}
func (p *process) Pid() int {
return p.containerPid
}
func (p *process) Wait() (rst uint32, rerr error) {
var b []byte
if _, err := p.exit.Read(b); err != nil {
return 255, err
}
data, err := ioutil.ReadFile(filepath.Join(p.root, "exitStatus"))
defer func() {
if rerr != nil {
rst, rerr = p.handleSigkilledShim(rst, rerr)
}
}()
if err != nil {
if os.IsNotExist(err) {
return UnknownStatus, ErrProcessNotExited
}
return UnknownStatus, err
}
if len(data) == 0 {
return UnknownStatus, ErrProcessNotExited
}
i, err := strconv.ParseUint(string(data), 10, 32)
return uint32(i), err
}
func (p *process) Signal(s os.Signal) error {
_, err := fmt.Fprintf(p.control, "%d %d %d\n", 2, s, 0)
return err
}
// same checks if the process is the same process originally launched
@ -39,7 +209,7 @@ func (p *process) same() (bool, error) {
if p.startTime == "" {
return true, nil
}
pid, err := p.readContainerPid()
pid, err := readPid(filepath.Join(p.root, "pid"))
if err != nil {
return false, nil
}
@ -57,15 +227,15 @@ func (p *process) checkExited() {
}
if same, _ := p.same(); same && p.hasPid() {
// The process changed its PR_SET_PDEATHSIG, so force kill it
logrus.Infof("containerd: %s:%s (pid %v) has become an orphan, killing it", p.container.id, p.namae, p.containerPid)
logrus.Infof("containerd: (pid %v) has become an orphan, killing it", p.containerPid)
if err := unix.Kill(p.containerPid, syscall.SIGKILL); err != nil && err != syscall.ESRCH {
logrus.Errorf("containerd: unable to SIGKILL %s:%s (pid %v): %v", p.container.id, p.name, p.containerPid, err)
logrus.Errorf("containerd: unable to SIGKILL (pid %v): %v", p.containerPid, err)
close(p.done)
return
}
// wait for the container process to exit
for {
if err := unix.Kill(p.pid, 0); err != nil {
if err := unix.Kill(p.containerPid, 0); err != nil {
break
}
time.Sleep(5 * time.Millisecond)
@ -92,9 +262,9 @@ type pidResponse struct {
err error
}
func (p *process) waitForCreate() error {
func (p *process) waitForCreate(timeout time.Duration) error {
r := make(chan pidResponse, 1)
go readContainerPid(wc)
go p.readContainerPid(r)
select {
case resp := <-r:
@ -104,24 +274,27 @@ func (p *process) waitForCreate() error {
p.setPid(resp.pid)
started, err := readProcessStartTime(resp.pid)
if err != nil {
logrus.Warnf("containerd: unable to save %s:%s starttime: %v", p.container.id, p.id, err)
logrus.Warnf("containerd: unable to save starttime: %v", err)
}
// TODO: save start time to disk or process state file
p.startTime = started
return nil
case <-time.After(c.timeout):
case <-time.After(timeout):
p.cmd.Process.Kill()
p.cmd.Wait()
return ErrContainerStartTimeout
}
}
func readContainerPid(r chan pidResponse, pidFile string) {
func (p *process) readContainerPid(r chan pidResponse) {
pidFile := filepath.Join(p.root, "pid")
for {
pid, err := readContainerPid(pidFile)
pid, err := readPid(pidFile)
if err != nil {
if os.IsNotExist(err) || err == errInvalidPidInt {
if serr := checkErrorLogs(); serr != nil {
if serr := checkErrorLogs(p.cmd,
filepath.Join(p.root, "shim-log.json"),
filepath.Join(p.root, "log.json")); serr != nil {
r <- pidResponse{
err: err,
}
@ -142,6 +315,45 @@ func readContainerPid(r chan pidResponse, pidFile string) {
}
}
func (p *process) handleSigkilledShim(rst uint32, rerr error) (uint32, error) {
if err := unix.Kill(p.containerPid, 0); err == syscall.ESRCH {
logrus.Warnf("containerd: (pid %d) does not exist", p.containerPid)
// The process died while containerd was down (probably of
// SIGKILL, but no way to be sure)
return UnknownStatus, writeExitStatus(filepath.Join(p.root, "exitStatus"), UnknownStatus)
}
// If it's not the same process, just mark it stopped and set
// the status to the UnknownStatus value (i.e. 255)
if same, _ := p.same(); !same {
// Create the file so we get the exit event generated once monitor kicks in
// without having to go through all this process again
return UnknownStatus, writeExitStatus(filepath.Join(p.root, "exitStatus"), UnknownStatus)
}
ppid, err := readProcStatField(p.containerPid, 4)
if err != nil {
return rst, fmt.Errorf("could not check process ppid: %v (%v)", err, rerr)
}
if ppid == "1" {
if err := unix.Kill(p.containerPid, syscall.SIGKILL); err != nil && err != syscall.ESRCH {
return UnknownStatus, fmt.Errorf(
"containerd: unable to SIGKILL (pid %v): %v", p.containerPid, err)
}
// wait for the process to die
for {
if err := unix.Kill(p.containerPid, 0); err == syscall.ESRCH {
break
}
time.Sleep(5 * time.Millisecond)
}
// Create the file so we get the exit event generated once monitor kicks in
// without having to go through all this process again
status := 128 + uint32(syscall.SIGKILL)
return status, writeExitStatus(filepath.Join(p.root, "exitStatus"), status)
}
return rst, rerr
}
func checkErrorLogs(cmd *exec.Cmd, shimLogPath, runtimeLogPath string) error {
alive, err := isAlive(cmd)
if err != nil {
@ -200,7 +412,7 @@ func readProcStatField(pid int, field int) (string, error) {
return strings.Split(parts[1], ") ")[0], nil
}
func readContainerPid(pidFile string) (int, error) {
func readPid(pidFile string) (int, error) {
data, err := ioutil.ReadFile(pidFile)
if err != nil {
return -1, nil
@ -251,3 +463,23 @@ func readLogMessages(path string) ([]message, error) {
}
return out, nil
}
func getExitPipe(path string) (*os.File, error) {
if err := unix.Mkfifo(path, 0755); err != nil && !os.IsExist(err) {
return nil, err
}
// add NONBLOCK in case the other side has already closed or else
// this function would never return
return os.OpenFile(path, syscall.O_RDONLY|syscall.O_NONBLOCK, 0)
}
func getControlPipe(path string) (*os.File, error) {
if err := unix.Mkfifo(path, 0755); err != nil && !os.IsExist(err) {
return nil, err
}
return os.OpenFile(path, syscall.O_RDWR|syscall.O_NONBLOCK, 0)
}
func writeExitStatus(path string, status uint32) error {
return ioutil.WriteFile(path, []byte(fmt.Sprintf("%u", status)), 0644)
}

229
shim/shim.go
View File

@ -2,6 +2,7 @@ package shim
import (
"encoding/json"
"errors"
"fmt"
"os"
"os/exec"
@ -12,6 +13,7 @@ import (
"github.com/docker/containerd/oci"
"github.com/docker/containerkit"
specs "github.com/opencontainers/runtime-spec/specs-go"
)
/*
@ -27,57 +29,64 @@ import (
│   │   │   ├── shim-log.json
│   │   │   └── starttime
│   │   └── state.json
│   └── ff2e86955c2be43f0e3c300fbd3786599301bd8efcaa5a386587f132e73af242
│   ├── config.json
│   ├── init-stderr
│   ├── init-stdin
│   └── init-stdout
*/
type Opts struct {
Name string
RuntimeName string
RuntimeLogFile string
RuntimeArgs []string
Root string
Timeout time.Duration
}
var (
ErrNotFifo = errors.New("shim: IO is not a valid fifo on disk")
errInitProcessNotExist = errors.New("shim: init process does not exist")
)
type state struct {
Bundle string `json:"bundle"`
Stdin string `json:"stdin"`
Stdout string `json:"stdout"`
Stderr string `json:"stderr"`
Runtime string `json:"runtime"`
RuntimeArgs []string `json:"runtimeArgs"`
Shim string `json:"shim"`
NoPivotRoot bool `json:"noPivotRoot"`
type Opts struct {
Name string
RuntimeName string
RuntimeArgs []string
NoPivotRoot bool
Root string
Timeout time.Duration
}
func New(opts Opts) (*Shim, error) {
if err := os.MkdirAll(opts.Root, 0711); err != nil {
if err := os.Mkdir(opts.Root, 0711); err != nil {
return nil, err
}
r, err := oci.New(oci.Opts{
Name: opts.RuntimeName,
LogFile: opts.RuntimeLogFile,
Args: opts.RuntimeArgs,
Name: opts.RuntimeName,
Args: opts.RuntimeArgs,
})
if err != nil {
return nil, err
}
return &Shim{
root: opts.Root,
name: opts.Name,
timeout: opts.Timeout,
runtime: r,
}, nil
s := &Shim{
root: opts.Root,
name: opts.Name,
timeout: opts.Timeout,
runtime: r,
processes: make(map[string]*process),
}
f, err := os.Create(filepath.Join(opts.Root, "state.json"))
if err != nil {
return nil, err
}
err = json.NewEncoder(f).Encode(s)
f.Close()
return s, err
}
// Load will load an existing shim with all its information restored from the
// provided path
func Load(path string) (*Shim, error) {
func Load(root string) (*Shim, error) {
f, err := os.Open(filepath.Join(root, "state.json"))
if err != nil {
return nil, err
}
var s Shim
err = json.NewDecoder(f).Decode(&s)
f.Close()
if err != nil {
return nil, err
}
// TODO: read processes into memory
return &s, nil
}
// Shim is a container runtime that adds a shim process as the container's parent
@ -88,50 +97,82 @@ func Load(path string) (*Shim, error) {
type Shim struct {
// root holds runtime state information for the containers
// launched by the runtime
root string
// name is the name of the runtime, i.e. runc
name string
timeout time.Duration
root string
name string
timeout time.Duration
noPivotRoot bool
runtime *oci.OCIRuntime
pmu sync.Mutex
processes map[string]*process
bundle string
checkpoint string
}
runtime *oci.OCIRuntime
pmu sync.Mutex
initProcesses map[string]*process
type state struct {
// Bundle is the path to the container's bundle
Bundle string `json:"bundle"`
// OCI runtime binary name
Runtime string `json:"runtime"`
// OCI runtime args
RuntimeArgs []string `json:"runtimeArgs"`
// Shim binary name
Name string `json:"shim"`
/// NoPivotRoot option
NoPivotRoot bool `json:"noPivotRoot"`
// Timeout for container start
Timeout time.Duration `json:"timeout"`
}
func (s *Shim) MarshalJSON() ([]byte, error) {
st := state{
Name: s.name,
Bundle: s.bundle,
Runtime: s.runtime.Name(),
RuntimeArgs: s.runtime.Args(),
NoPivotRoot: s.noPivotRoot,
Timeout: s.timeout,
}
return json.Marshal(st)
}
func (s *Shim) UnmarshalJSON(b []byte) error {
var st state
if err := json.Unmarshal(b, &st); err != nil {
return err
}
s.name = st.Name
s.bundle = st.Bundle
s.timeout = st.Timeout
s.noPivotRoot = st.NoPivotRoot
r, err := oci.New(oci.Opts{
Name: st.Runtime,
Args: st.RuntimeArgs,
})
if err != nil {
return err
}
s.runtime = r
return nil
}
func (s *Shim) Create(c *containerkit.Container) (containerkit.ProcessDelegate, error) {
if err := os.Mkdir(filepath.Join(c.root, c.id), 0711); err != nil {
return nil, err
}
f, err := os.Create(filepath.Join(c.root, c.id, StateFile))
if err != nil {
return nil, err
}
err = json.NewEncoder(f).Encode(state{
Bundle: c.bundle,
Labels: c.labels,
Runtime: c.runtime,
RuntimeArgs: c.runtimeArgs,
Shim: c.shim,
NoPivotRoot: opts.NoPivotRoot,
})
f.Close()
if err != nil {
return nil, err
}
cmd := s.command(c.ID(), c.Path(), s.runtime.Name())
var (
root = filepath.Join(s.root, "init")
cmd = s.command(c.ID(), c.Path(), s.runtime.Name())
)
// exec the shim inside the state directory setup with the process
// information for what is being run
cmd.Dir = processRoot
cmd.Dir = root
// make sure the shim is in a new process group
cmd.SysProcAttr = &syscall.SysProcAttr{
Setpgid: true,
}
p, err := s.startCommand("init", cmd)
p, err := s.startCommand(c, cmd)
if err != nil {
return nil, err
}
s.pmu.Lock()
s.initProcesses[c.ID()] = p
s.processes["init"] = p
s.pmu.Unlock()
// ~TODO: oom and stats stuff here
return p, nil
@ -176,7 +217,7 @@ func (s *Shim) Start(c *containerkit.Container) error {
func (s *Shim) getContainerInit(c *containerkit.Container) (*process, error) {
s.pmu.Lock()
p, ok := s.initProcesses[c.ID()]
p, ok := s.processes["init"]
s.pmu.Unlock()
if !ok {
return nil, errInitProcessNotExist
@ -184,17 +225,15 @@ func (s *Shim) getContainerInit(c *containerkit.Container) (*process, error) {
return p, nil
}
func (s *Shim) startCommand(processName string, cmd *exec.Cmd) (*process, error) {
p := &process{
name: processName,
cmd: cmd,
done: make(chan struct{}),
timeout: s.timeout,
func (s *Shim) startCommand(c *containerkit.Container, cmd *exec.Cmd) (*process, error) {
p, err := newProcess(filepath.Join(s.root, "init"), s.noPivotRoot, s.checkpoint, c, cmd)
if err != nil {
return nil, err
}
if err := cmd.Start(); err != nil {
close(proc.done)
close(p.done)
if checkShimNotFound(err) {
return fmt.Errorf("%s not install on system", s.name)
return nil, fmt.Errorf("%s not install on system", s.name)
}
return nil, err
}
@ -202,7 +241,7 @@ func (s *Shim) startCommand(processName string, cmd *exec.Cmd) (*process, error)
defer func() {
go p.checkExited()
}()
if err := p.waitForCreate(); err != nil {
if err := p.waitForCreate(s.timeout); err != nil {
return nil, err
}
return p, nil
@ -221,3 +260,45 @@ func checkShimNotFound(err error) bool {
}
return false
}
// getFifoPath returns the path to the fifo on disk as long as the provided
// interface is an *os.File and has a valid path on the Name() method call
func getFifoPath(v interface{}) (string, error) {
f, ok := v.(*os.File)
if !ok {
return "", ErrNotFifo
}
p := f.Name()
if p == "" {
return "", ErrNotFifo
}
return p, nil
}
func getRootIDs(s *specs.Spec) (int, int, error) {
if s == nil {
return 0, 0, nil
}
var hasUserns bool
for _, ns := range s.Linux.Namespaces {
if ns.Type == specs.UserNamespace {
hasUserns = true
break
}
}
if !hasUserns {
return 0, 0, nil
}
uid := hostIDFromMap(0, s.Linux.UIDMappings)
gid := hostIDFromMap(0, s.Linux.GIDMappings)
return uid, gid, nil
}
func hostIDFromMap(id uint32, mp []specs.IDMapping) int {
for _, m := range mp {
if (id >= m.ContainerID) && (id <= (m.ContainerID + m.Size - 1)) {
return int(m.HostID + (id - m.ContainerID))
}
}
return 0
}