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