func (srv *Server) DockerInfo() *APIInfo {
	images, _ := srv.runtime.graph.Map()
	var imgcount int
	if images == nil {
		imgcount = 0
	} else {
		imgcount = len(images)
	}
	lxcVersion := ""
	if output, err := exec.Command("lxc-version").CombinedOutput(); err == nil {
		outputStr := string(output)
		if len(strings.SplitN(outputStr, ":", 2)) == 2 {
			lxcVersion = strings.TrimSpace(strings.SplitN(string(output), ":", 2)[1])
		}
	}
	kernelVersion := "<unknown>"
	if kv, err := utils.GetKernelVersion(); err == nil {
		kernelVersion = kv.String()
	}

	return &APIInfo{
		Containers:         len(srv.runtime.List()),
		Images:             imgcount,
		MemoryLimit:        srv.runtime.capabilities.MemoryLimit,
		SwapLimit:          srv.runtime.capabilities.SwapLimit,
		IPv4Forwarding:     !srv.runtime.capabilities.IPv4ForwardingDisabled,
		Debug:              os.Getenv("DEBUG") != "",
		NFd:                utils.GetTotalUsedFds(),
		NGoroutines:        runtime.NumGoroutine(),
		LXCVersion:         lxcVersion,
		NEventsListener:    len(srv.events),
		KernelVersion:      kernelVersion,
		IndexServerAddress: auth.IndexServerAddress(),
	}
}

// New initializes a new engine managing the directory specified at `root`.
// `root` is used to store containers and any other state private to the engine.
// Changing the contents of the root without executing a job will cause unspecified
// behavior.
func New(root string) (*Engine, error) {
	// Check for unsupported architectures
	if runtime.GOARCH != "amd64" {
		return nil, fmt.Errorf("The docker runtime currently only supports amd64 (not %s). This will change in the future. Aborting.", runtime.GOARCH)
	}
	// Check for unsupported kernel versions
	// FIXME: it would be cleaner to not test for specific versions, but rather
	// test for specific functionalities.
	// Unfortunately we can't test for the feature "does not cause a kernel panic"
	// without actually causing a kernel panic, so we need this workaround until
	// the circumstances of pre-3.8 crashes are clearer.
	// For details see http://github.com/dotcloud/docker/issues/407
	if k, err := utils.GetKernelVersion(); err != nil {
		log.Printf("WARNING: %s\n", err)
	} else {
		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())
		}
	}
	if err := os.MkdirAll(root, 0700); err != nil && !os.IsExist(err) {
		return nil, err
	}
	eng := &Engine{
		root:     root,
		handlers: globalHandlers,
	}
	return eng, nil
}

// New initializes a new engine managing the directory specified at `root`.
// `root` is used to store containers and any other state private to the engine.
// Changing the contents of the root without executing a job will cause unspecified
// behavior.
func New(root string) (*Engine, error) {
	// Check for unsupported architectures
	if runtime.GOARCH != "amd64" {
		return nil, fmt.Errorf("The docker runtime currently only supports amd64 (not %s). This will change in the future. Aborting.", runtime.GOARCH)
	}
	// Check for unsupported kernel versions
	// FIXME: it would be cleaner to not test for specific versions, but rather
	// test for specific functionalities.
	// Unfortunately we can't test for the feature "does not cause a kernel panic"
	// without actually causing a kernel panic, so we need this workaround until
	// the circumstances of pre-3.8 crashes are clearer.
	// For details see http://github.com/dotcloud/docker/issues/407
	if k, err := utils.GetKernelVersion(); err != nil {
		log.Printf("WARNING: %s\n", err)
	} else {
		if utils.CompareKernelVersion(k, &utils.KernelVersionInfo{Kernel: 3, Major: 8, Minor: 0}) < 0 {
			if os.Getenv("DOCKER_NOWARN_KERNEL_VERSION") == "" {
				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())
			}
		}
	}

	if err := os.MkdirAll(root, 0700); err != nil && !os.IsExist(err) {
		return nil, err
	}

	// Docker makes some assumptions about the "absoluteness" of root
	// ... so let's make sure it has no symlinks
	if p, err := filepath.Abs(root); err != nil {
		log.Fatalf("Unable to get absolute root (%s): %s", root, err)
	} else {
		root = p
	}
	if p, err := filepath.EvalSymlinks(root); err != nil {
		log.Fatalf("Unable to canonicalize root (%s): %s", root, err)
	} else {
		root = p
	}

	eng := &Engine{
		root:     root,
		handlers: make(map[string]Handler),
		id:       utils.RandomString(),
		Stdout:   os.Stdout,
		Stderr:   os.Stderr,
		Stdin:    os.Stdin,
	}
	eng.Register("commands", func(job *Job) Status {
		for _, name := range eng.commands() {
			job.Printf("%s\n", name)
		}
		return StatusOK
	})
	// Copy existing global handlers
	for k, v := range globalHandlers {
		eng.handlers[k] = v
	}
	return eng, nil
}

func createBridgeIface(name string) error {
	kv, err := utils.GetKernelVersion()
	// only set the bridge's mac address if the kernel version is > 3.3
	// before that it was not supported
	setBridgeMacAddr := err == nil && (kv.Kernel >= 3 && kv.Major >= 3)
	utils.Debugf("setting bridge mac address = %v", setBridgeMacAddr)
	return netlink.CreateBridge(name, setBridgeMacAddr)
}

// dockerVersion returns detailed version information in the form of a queriable
// environment.
func dockerVersion() *engine.Env {
	v := &engine.Env{}
	v.Set("Version", VERSION)
	v.Set("GitCommit", GITCOMMIT)
	v.Set("GoVersion", runtime.Version())
	// FIXME:utils.GetKernelVersion should only be needed here
	if kernelVersion, err := utils.GetKernelVersion(); err == nil {
		v.Set("KernelVersion", kernelVersion.String())
	}
	return v
}

// FIXME: harmonize with NewGraph()
func NewRuntime(config *DaemonConfig) (*Runtime, error) {
	runtime, err := NewRuntimeFromDirectory(config)
	if err != nil {
		return nil, err
	}

	if k, err := utils.GetKernelVersion(); err != nil {
		log.Printf("WARNING: %s\n", err)
	} else {
		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
}

// versionCheckers() returns version informations of:
// docker, go, git-commit (of the docker) and the host's kernel.
//
// Such information will be used on call to NewRegistry().
func (srv *Server) versionInfos() []utils.VersionInfo {
	v := srv.DockerVersion()
	ret := append(make([]utils.VersionInfo, 0, 4), &simpleVersionInfo{"docker", v.Version})

	if len(v.GoVersion) > 0 {
		ret = append(ret, &simpleVersionInfo{"go", v.GoVersion})
	}
	if len(v.GitCommit) > 0 {
		ret = append(ret, &simpleVersionInfo{"git-commit", v.GitCommit})
	}
	if kernelVersion, err := utils.GetKernelVersion(); err == nil {
		ret = append(ret, &simpleVersionInfo{"kernel", kernelVersion.String()})
	}

	return ret
}

// builtins jobs independent of any subsystem
func dockerVersion(job *engine.Job) engine.Status {
	v := &engine.Env{}
	v.Set("Version", dockerversion.VERSION)
	v.SetJson("ApiVersion", api.APIVERSION)
	v.Set("GitCommit", dockerversion.GITCOMMIT)
	v.Set("GoVersion", runtime.Version())
	v.Set("Os", runtime.GOOS)
	v.Set("Arch", runtime.GOARCH)
	if kernelVersion, err := utils.GetKernelVersion(); err == nil {
		v.Set("KernelVersion", kernelVersion.String())
	}
	if _, err := v.WriteTo(job.Stdout); err != nil {
		return job.Error(err)
	}
	return engine.StatusOK
}

func HTTPRequestFactory(metaHeaders map[string][]string) *utils.HTTPRequestFactory {
	// FIXME: this replicates the 'info' job.
	httpVersion := make([]utils.VersionInfo, 0, 4)
	httpVersion = append(httpVersion, &simpleVersionInfo{"docker", dockerversion.VERSION})
	httpVersion = append(httpVersion, &simpleVersionInfo{"go", runtime.Version()})
	httpVersion = append(httpVersion, &simpleVersionInfo{"git-commit", dockerversion.GITCOMMIT})
	if kernelVersion, err := utils.GetKernelVersion(); err == nil {
		httpVersion = append(httpVersion, &simpleVersionInfo{"kernel", kernelVersion.String()})
	}
	httpVersion = append(httpVersion, &simpleVersionInfo{"os", runtime.GOOS})
	httpVersion = append(httpVersion, &simpleVersionInfo{"arch", runtime.GOARCH})
	ud := utils.NewHTTPUserAgentDecorator(httpVersion...)
	md := &utils.HTTPMetaHeadersDecorator{
		Headers: metaHeaders,
	}
	factory := utils.NewHTTPRequestFactory(ud, md)
	return factory
}

// 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 checkKernelAndArch() error {
	// Check for unsupported architectures
	if runtime.GOARCH != "amd64" {
		return fmt.Errorf("The Docker runtime currently only supports amd64 (not %s). This will change in the future. Aborting.", runtime.GOARCH)
	}
	// Check for unsupported kernel versions
	// FIXME: it would be cleaner to not test for specific versions, but rather
	// test for specific functionalities.
	// Unfortunately we can't test for the feature "does not cause a kernel panic"
	// without actually causing a kernel panic, so we need this workaround until
	// the circumstances of pre-3.8 crashes are clearer.
	// For details see http://github.com/dotcloud/docker/issues/407
	if k, err := utils.GetKernelVersion(); err != nil {
		log.Printf("WARNING: %s\n", err)
	} else {
		if utils.CompareKernelVersion(k, &utils.KernelVersionInfo{Kernel: 3, Major: 8, Minor: 0}) < 0 {
			if os.Getenv("DOCKER_NOWARN_KERNEL_VERSION") == "" {
				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())
			}
		}
	}
	return nil
}