520 lines
15 KiB
Go
520 lines
15 KiB
Go
package docker
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import (
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"container/list"
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"fmt"
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"github.com/dotcloud/docker/utils"
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"io"
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"io/ioutil"
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"log"
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"os"
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"os/exec"
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"path"
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"sort"
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"strings"
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"time"
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)
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var defaultDns = []string{"8.8.8.8", "8.8.4.4"}
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type Capabilities struct {
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MemoryLimit bool
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SwapLimit bool
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IPv4ForwardingDisabled bool
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}
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type Runtime struct {
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root string
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repository string
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containers *list.List
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networkManager *NetworkManager
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graph *Graph
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repositories *TagStore
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idIndex *utils.TruncIndex
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capabilities *Capabilities
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kernelVersion *utils.KernelVersionInfo
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autoRestart bool
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volumes *Graph
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srv *Server
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Dns []string
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}
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var sysInitPath string
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func init() {
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sysInitPath = utils.SelfPath()
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}
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// List returns an array of all containers registered in the runtime.
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func (runtime *Runtime) List() []*Container {
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containers := new(History)
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for e := runtime.containers.Front(); e != nil; e = e.Next() {
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containers.Add(e.Value.(*Container))
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}
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return *containers
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}
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func (runtime *Runtime) getContainerElement(id string) *list.Element {
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for e := runtime.containers.Front(); e != nil; e = e.Next() {
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container := e.Value.(*Container)
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if container.ID == id {
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return e
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}
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}
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return nil
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}
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// Get looks for a container by the specified ID or name, and returns it.
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// If the container is not found, or if an error occurs, nil is returned.
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func (runtime *Runtime) Get(name string) *Container {
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id, err := runtime.idIndex.Get(name)
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if err != nil {
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return nil
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}
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e := runtime.getContainerElement(id)
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if e == nil {
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return nil
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}
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return e.Value.(*Container)
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}
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// Exists returns a true if a container of the specified ID or name exists,
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// false otherwise.
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func (runtime *Runtime) Exists(id string) bool {
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return runtime.Get(id) != nil
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}
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func (runtime *Runtime) containerRoot(id string) string {
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return path.Join(runtime.repository, id)
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}
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// Load reads the contents of a container from disk and registers
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// it with Register.
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// This is typically done at startup.
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func (runtime *Runtime) Load(id string) (*Container, error) {
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container := &Container{root: runtime.containerRoot(id)}
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if err := container.FromDisk(); err != nil {
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return nil, err
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}
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if container.ID != id {
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return container, fmt.Errorf("Container %s is stored at %s", container.ID, id)
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}
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if container.State.Running {
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container.State.Ghost = true
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}
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if err := runtime.Register(container); err != nil {
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return nil, err
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}
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return container, nil
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}
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// Register makes a container object usable by the runtime as <container.ID>
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func (runtime *Runtime) Register(container *Container) error {
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if container.runtime != nil || runtime.Exists(container.ID) {
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return fmt.Errorf("Container is already loaded")
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}
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if err := validateID(container.ID); err != nil {
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return err
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}
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// init the wait lock
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container.waitLock = make(chan struct{})
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container.runtime = runtime
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// Attach to stdout and stderr
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container.stderr = utils.NewWriteBroadcaster()
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container.stdout = utils.NewWriteBroadcaster()
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// Attach to stdin
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if container.Config.OpenStdin {
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container.stdin, container.stdinPipe = io.Pipe()
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} else {
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container.stdinPipe = utils.NopWriteCloser(ioutil.Discard) // Silently drop stdin
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}
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// done
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runtime.containers.PushBack(container)
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runtime.idIndex.Add(container.ID)
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// When we actually restart, Start() do the monitoring.
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// However, when we simply 'reattach', we have to restart a monitor
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nomonitor := false
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// FIXME: if the container is supposed to be running but is not, auto restart it?
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// if so, then we need to restart monitor and init a new lock
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// If the container is supposed to be running, make sure of it
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if container.State.Running {
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output, err := exec.Command("lxc-info", "-n", container.ID).CombinedOutput()
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if err != nil {
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return err
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}
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if !strings.Contains(string(output), "RUNNING") {
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utils.Debugf("Container %s was supposed to be running be is not.", container.ID)
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if runtime.autoRestart {
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utils.Debugf("Restarting")
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container.State.Ghost = false
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container.State.setStopped(0)
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hostConfig := &HostConfig{}
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if err := container.Start(hostConfig); err != nil {
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return err
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}
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nomonitor = true
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} else {
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utils.Debugf("Marking as stopped")
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container.State.setStopped(-127)
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if err := container.ToDisk(); err != nil {
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return err
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}
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}
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}
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}
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// If the container is not running or just has been flagged not running
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// then close the wait lock chan (will be reset upon start)
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if !container.State.Running {
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close(container.waitLock)
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} else if !nomonitor {
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container.allocateNetwork()
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go container.monitor()
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}
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return nil
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}
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func (runtime *Runtime) LogToDisk(src *utils.WriteBroadcaster, dst, stream string) error {
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log, err := os.OpenFile(dst, os.O_RDWR|os.O_APPEND|os.O_CREATE, 0600)
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if err != nil {
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return err
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}
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src.AddWriter(log, stream)
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return nil
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}
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// Destroy unregisters a container from the runtime and cleanly removes its contents from the filesystem.
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func (runtime *Runtime) Destroy(container *Container) error {
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if container == nil {
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return fmt.Errorf("The given container is <nil>")
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}
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element := runtime.getContainerElement(container.ID)
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if element == nil {
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return fmt.Errorf("Container %v not found - maybe it was already destroyed?", container.ID)
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}
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if err := container.Stop(3); err != nil {
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return err
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}
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if mounted, err := container.Mounted(); err != nil {
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return err
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} else if mounted {
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if err := container.Unmount(); err != nil {
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return fmt.Errorf("Unable to unmount container %v: %v", container.ID, err)
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}
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}
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// Deregister the container before removing its directory, to avoid race conditions
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runtime.idIndex.Delete(container.ID)
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runtime.containers.Remove(element)
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if err := os.RemoveAll(container.root); err != nil {
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return fmt.Errorf("Unable to remove filesystem for %v: %v", container.ID, err)
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}
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return nil
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}
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func (runtime *Runtime) restore() error {
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wheel := "-\\|/"
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if os.Getenv("DEBUG") == "" && os.Getenv("TEST") == "" {
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fmt.Printf("Loading containers: ")
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}
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dir, err := ioutil.ReadDir(runtime.repository)
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if err != nil {
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return err
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}
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for i, v := range dir {
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id := v.Name()
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container, err := runtime.Load(id)
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if i%21 == 0 && os.Getenv("DEBUG") == "" && os.Getenv("TEST") == "" {
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fmt.Printf("\b%c", wheel[i%4])
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}
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if err != nil {
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utils.Debugf("Failed to load container %v: %v", id, err)
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continue
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}
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utils.Debugf("Loaded container %v", container.ID)
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}
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if os.Getenv("DEBUG") == "" && os.Getenv("TEST") == "" {
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fmt.Printf("\bdone.\n")
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}
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return nil
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}
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// FIXME: comment please!
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func (runtime *Runtime) UpdateCapabilities(quiet bool) {
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if cgroupMemoryMountpoint, err := utils.FindCgroupMountpoint("memory"); err != nil {
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if !quiet {
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log.Printf("WARNING: %s\n", err)
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}
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} else {
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_, err1 := ioutil.ReadFile(path.Join(cgroupMemoryMountpoint, "memory.limit_in_bytes"))
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_, err2 := ioutil.ReadFile(path.Join(cgroupMemoryMountpoint, "memory.soft_limit_in_bytes"))
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runtime.capabilities.MemoryLimit = err1 == nil && err2 == nil
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if !runtime.capabilities.MemoryLimit && !quiet {
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log.Printf("WARNING: Your kernel does not support cgroup memory limit.")
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}
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_, err = ioutil.ReadFile(path.Join(cgroupMemoryMountpoint, "memory.memsw.limit_in_bytes"))
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runtime.capabilities.SwapLimit = err == nil
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if !runtime.capabilities.SwapLimit && !quiet {
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log.Printf("WARNING: Your kernel does not support cgroup swap limit.")
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}
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}
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content, err3 := ioutil.ReadFile("/proc/sys/net/ipv4/ip_forward")
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runtime.capabilities.IPv4ForwardingDisabled = err3 != nil || len(content) == 0 || content[0] != '1'
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if runtime.capabilities.IPv4ForwardingDisabled && !quiet {
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log.Printf("WARNING: IPv4 forwarding is disabled.")
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}
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}
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// Create creates a new container from the given configuration.
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func (runtime *Runtime) Create(config *Config) (*Container, error) {
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// Lookup image
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img, err := runtime.repositories.LookupImage(config.Image)
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if err != nil {
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return nil, err
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}
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if img.Config != nil {
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if err := MergeConfig(config, img.Config); err != nil {
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return nil, err
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}
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}
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if len(config.Entrypoint) != 0 && config.Cmd == nil {
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config.Cmd = []string{}
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} else if config.Cmd == nil || len(config.Cmd) == 0 {
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return nil, fmt.Errorf("No command specified")
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}
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// Generate id
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id := GenerateID()
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// Generate default hostname
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// FIXME: the lxc template no longer needs to set a default hostname
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if config.Hostname == "" {
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config.Hostname = id[:12]
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}
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var args []string
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var entrypoint string
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if len(config.Entrypoint) != 0 {
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entrypoint = config.Entrypoint[0]
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args = append(config.Entrypoint[1:], config.Cmd...)
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} else {
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entrypoint = config.Cmd[0]
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args = config.Cmd[1:]
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}
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container := &Container{
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// FIXME: we should generate the ID here instead of receiving it as an argument
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ID: id,
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Created: time.Now(),
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Path: entrypoint,
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Args: args, //FIXME: de-duplicate from config
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Config: config,
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Image: img.ID, // Always use the resolved image id
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NetworkSettings: &NetworkSettings{},
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// FIXME: do we need to store this in the container?
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SysInitPath: sysInitPath,
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}
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container.root = runtime.containerRoot(container.ID)
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// Step 1: create the container directory.
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// This doubles as a barrier to avoid race conditions.
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if err := os.Mkdir(container.root, 0700); err != nil {
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return nil, err
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}
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resolvConf, err := utils.GetResolvConf()
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if err != nil {
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return nil, err
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}
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if len(config.Dns) == 0 && len(runtime.Dns) == 0 && utils.CheckLocalDns(resolvConf) {
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//"WARNING: Docker detected local DNS server on resolv.conf. Using default external servers: %v", defaultDns
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runtime.Dns = defaultDns
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}
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// If custom dns exists, then create a resolv.conf for the container
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if len(config.Dns) > 0 || len(runtime.Dns) > 0 {
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var dns []string
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if len(config.Dns) > 0 {
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dns = config.Dns
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} else {
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dns = runtime.Dns
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}
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container.ResolvConfPath = path.Join(container.root, "resolv.conf")
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f, err := os.Create(container.ResolvConfPath)
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if err != nil {
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return nil, err
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}
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defer f.Close()
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for _, dns := range dns {
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if _, err := f.Write([]byte("nameserver " + dns + "\n")); err != nil {
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return nil, err
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}
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}
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} else {
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container.ResolvConfPath = "/etc/resolv.conf"
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}
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// Step 2: save the container json
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if err := container.ToDisk(); err != nil {
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return nil, err
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}
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// Step 3: if hostname, build hostname and hosts files
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container.HostnamePath = path.Join(container.root, "hostname")
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ioutil.WriteFile(container.HostnamePath, []byte(container.Config.Hostname+"\n"), 0644)
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hostsContent := []byte(`
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127.0.0.1 localhost
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::1 localhost ip6-localhost ip6-loopback
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fe00::0 ip6-localnet
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ff00::0 ip6-mcastprefix
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ff02::1 ip6-allnodes
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ff02::2 ip6-allrouters
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`)
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container.HostsPath = path.Join(container.root, "hosts")
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if container.Config.Domainname != "" {
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hostsContent = append([]byte(fmt.Sprintf("::1\t\t%s.%s %s\n", container.Config.Hostname, container.Config.Domainname, container.Config.Hostname)), hostsContent...)
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hostsContent = append([]byte(fmt.Sprintf("127.0.0.1\t%s.%s %s\n", container.Config.Hostname, container.Config.Domainname, container.Config.Hostname)), hostsContent...)
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} else {
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hostsContent = append([]byte(fmt.Sprintf("::1\t\t%s\n", container.Config.Hostname)), hostsContent...)
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hostsContent = append([]byte(fmt.Sprintf("127.0.0.1\t%s\n", container.Config.Hostname)), hostsContent...)
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}
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ioutil.WriteFile(container.HostsPath, hostsContent, 0644)
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// Step 4: register the container
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if err := runtime.Register(container); err != nil {
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return nil, err
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}
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return container, nil
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}
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// Commit creates a new filesystem image from the current state of a container.
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// The image can optionally be tagged into a repository
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func (runtime *Runtime) Commit(container *Container, repository, tag, comment, author string, config *Config) (*Image, error) {
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// FIXME: freeze the container before copying it to avoid data corruption?
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// FIXME: this shouldn't be in commands.
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if err := container.EnsureMounted(); err != nil {
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return nil, err
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}
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rwTar, err := container.ExportRw()
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if err != nil {
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return nil, err
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}
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// Create a new image from the container's base layers + a new layer from container changes
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img, err := runtime.graph.Create(rwTar, container, comment, author, config)
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if err != nil {
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return nil, err
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}
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// Register the image if needed
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if repository != "" {
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if err := runtime.repositories.Set(repository, tag, img.ID, true); err != nil {
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return img, err
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}
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}
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return img, nil
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}
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// FIXME: harmonize with NewGraph()
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func NewRuntime(flGraphPath string, autoRestart bool, dns []string) (*Runtime, error) {
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runtime, err := NewRuntimeFromDirectory(flGraphPath, autoRestart)
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if err != nil {
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return nil, err
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}
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runtime.Dns = dns
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if k, err := utils.GetKernelVersion(); err != nil {
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log.Printf("WARNING: %s\n", err)
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} else {
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runtime.kernelVersion = k
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if utils.CompareKernelVersion(k, &utils.KernelVersionInfo{Kernel: 3, Major: 8, Minor: 0}) < 0 {
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log.Printf("WARNING: You are running linux kernel version %s, which might be unstable running docker. Please upgrade your kernel to 3.8.0.", k.String())
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}
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}
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runtime.UpdateCapabilities(false)
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return runtime, nil
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}
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func NewRuntimeFromDirectory(root string, autoRestart bool) (*Runtime, error) {
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runtimeRepo := path.Join(root, "containers")
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if err := os.MkdirAll(runtimeRepo, 0700); err != nil && !os.IsExist(err) {
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return nil, err
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}
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g, err := NewGraph(path.Join(root, "graph"))
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if err != nil {
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return nil, err
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}
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volumes, err := NewGraph(path.Join(root, "volumes"))
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if err != nil {
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return nil, err
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}
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repositories, err := NewTagStore(path.Join(root, "repositories"), g)
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if err != nil {
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return nil, fmt.Errorf("Couldn't create Tag store: %s", err)
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}
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if NetworkBridgeIface == "" {
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NetworkBridgeIface = DefaultNetworkBridge
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}
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netManager, err := newNetworkManager(NetworkBridgeIface)
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if err != nil {
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return nil, err
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}
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runtime := &Runtime{
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root: root,
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repository: runtimeRepo,
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containers: list.New(),
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networkManager: netManager,
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graph: g,
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repositories: repositories,
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idIndex: utils.NewTruncIndex(),
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capabilities: &Capabilities{},
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autoRestart: autoRestart,
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volumes: volumes,
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}
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if err := runtime.restore(); err != nil {
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return nil, err
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}
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return runtime, nil
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}
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// History is a convenience type for storing a list of containers,
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// ordered by creation date.
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type History []*Container
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func (history *History) Len() int {
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return len(*history)
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}
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func (history *History) Less(i, j int) bool {
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containers := *history
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return containers[j].When().Before(containers[i].When())
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}
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func (history *History) Swap(i, j int) {
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containers := *history
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tmp := containers[i]
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containers[i] = containers[j]
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containers[j] = tmp
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}
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func (history *History) Add(container *Container) {
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*history = append(*history, container)
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sort.Sort(history)
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}
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