func (s *configureSuite) getCloudConfig(c *gc.C, stateServer bool, vers version.Binary) cloudinit.CloudConfig {
	var icfg *instancecfg.InstanceConfig
	var err error
	if stateServer {
		icfg, err = instancecfg.NewBootstrapInstanceConfig(constraints.Value{}, vers.Series)
		c.Assert(err, jc.ErrorIsNil)
		icfg.InstanceId = "instance-id"
		icfg.Jobs = []multiwatcher.MachineJob{multiwatcher.JobManageEnviron, multiwatcher.JobHostUnits}
	} else {
		icfg, err = instancecfg.NewInstanceConfig("0", "ya", imagemetadata.ReleasedStream, vers.Series, true, nil, nil, nil)
		c.Assert(err, jc.ErrorIsNil)
		icfg.Jobs = []multiwatcher.MachineJob{multiwatcher.JobHostUnits}
	}
	icfg.Tools = &tools.Tools{
		Version: vers,
		URL:     "http://testing.invalid/tools.tar.gz",
	}
	environConfig := testConfig(c, stateServer, vers)
	err = instancecfg.FinishInstanceConfig(icfg, environConfig)
	c.Assert(err, jc.ErrorIsNil)
	cloudcfg, err := cloudinit.New(icfg.Series)
	c.Assert(err, jc.ErrorIsNil)
	udata, err := cloudconfig.NewUserdataConfig(icfg, cloudcfg)
	c.Assert(err, jc.ErrorIsNil)
	err = udata.Configure()
	c.Assert(err, jc.ErrorIsNil)
	return cloudcfg
}

func (s *configureSuite) getCloudConfig(c *gc.C, controller bool, vers version.Binary) cloudinit.CloudConfig {
	var icfg *instancecfg.InstanceConfig
	var err error
	modelConfig := testConfig(c, controller, vers)
	if controller {
		icfg, err = instancecfg.NewBootstrapInstanceConfig(
			coretesting.FakeControllerConfig(),
			constraints.Value{}, constraints.Value{},
			vers.Series, "",
		)
		c.Assert(err, jc.ErrorIsNil)
		icfg.APIInfo = &api.Info{
			Password: "password",
			CACert:   coretesting.CACert,
			ModelTag: coretesting.ModelTag,
		}
		icfg.Controller.MongoInfo = &mongo.MongoInfo{
			Password: "password", Info: mongo.Info{CACert: coretesting.CACert},
		}
		icfg.Bootstrap.ControllerModelConfig = modelConfig
		icfg.Bootstrap.BootstrapMachineInstanceId = "instance-id"
		icfg.Bootstrap.HostedModelConfig = map[string]interface{}{
			"name": "hosted-model",
		}
		icfg.Bootstrap.StateServingInfo = params.StateServingInfo{
			Cert:         coretesting.ServerCert,
			PrivateKey:   coretesting.ServerKey,
			CAPrivateKey: coretesting.CAKey,
			StatePort:    123,
			APIPort:      456,
		}
		icfg.Jobs = []multiwatcher.MachineJob{multiwatcher.JobManageModel, multiwatcher.JobHostUnits}
		icfg.Bootstrap.StateServingInfo = params.StateServingInfo{
			Cert:         coretesting.ServerCert,
			PrivateKey:   coretesting.ServerKey,
			CAPrivateKey: coretesting.CAKey,
			StatePort:    123,
			APIPort:      456,
		}
	} else {
		icfg, err = instancecfg.NewInstanceConfig(coretesting.ControllerTag, "0", "ya", imagemetadata.ReleasedStream, vers.Series, nil)
		c.Assert(err, jc.ErrorIsNil)
		icfg.Jobs = []multiwatcher.MachineJob{multiwatcher.JobHostUnits}
	}
	err = icfg.SetTools(tools.List{
		&tools.Tools{
			Version: vers,
			URL:     "http://testing.invalid/tools.tar.gz",
		},
	})
	err = instancecfg.FinishInstanceConfig(icfg, modelConfig)
	c.Assert(err, jc.ErrorIsNil)
	cloudcfg, err := cloudinit.New(icfg.Series)
	c.Assert(err, jc.ErrorIsNil)
	udata, err := cloudconfig.NewUserdataConfig(icfg, cloudcfg)
	c.Assert(err, jc.ErrorIsNil)
	err = udata.Configure()
	c.Assert(err, jc.ErrorIsNil)
	return cloudcfg
}

func (s *localJujuTestSuite) testBootstrap(c *gc.C, cfg *config.Config) environs.Environ {
	ctx := envtesting.BootstrapContext(c)
	environ, err := local.Provider.PrepareForBootstrap(ctx, cfg)
	c.Assert(err, jc.ErrorIsNil)
	availableTools := coretools.List{&coretools.Tools{
		Version: version.Binary{
			Number: version.Current,
			Arch:   arch.HostArch(),
			Series: series.HostSeries(),
		},
		URL: "http://testing.invalid/tools.tar.gz",
	}}
	result, err := environ.Bootstrap(ctx, environs.BootstrapParams{
		AvailableTools: availableTools,
	})
	c.Assert(err, jc.ErrorIsNil)
	icfg, err := instancecfg.NewBootstrapInstanceConfig(
		constraints.Value{}, constraints.Value{}, "quantal", "",
	)
	c.Assert(err, jc.ErrorIsNil)
	icfg.Tools = availableTools[0]
	err = result.Finalize(ctx, icfg)
	c.Assert(err, jc.ErrorIsNil)
	return environ
}

func (s *BaseSuiteUnpatched) initInst(c *gc.C) {
	tools := []*tools.Tools{{
		Version: version.Binary{Arch: arch.AMD64, Series: "trusty"},
		URL:     "https://example.org",
	}}

	cons := constraints.Value{InstanceType: &allInstanceTypes[0].Name}

	instanceConfig, err := instancecfg.NewBootstrapInstanceConfig(cons, cons, "trusty", "")
	c.Assert(err, jc.ErrorIsNil)

	instanceConfig.Tools = tools[0]
	instanceConfig.AuthorizedKeys = s.Config.AuthorizedKeys()

	userData, err := providerinit.ComposeUserData(instanceConfig, nil, GCERenderer{})
	c.Assert(err, jc.ErrorIsNil)

	authKeys, err := google.FormatAuthorizedKeys(instanceConfig.AuthorizedKeys, "ubuntu")
	c.Assert(err, jc.ErrorIsNil)

	s.UbuntuMetadata = map[string]string{
		metadataKeyIsState:   metadataValueTrue,
		metadataKeyCloudInit: string(userData),
		metadataKeyEncoding:  "base64",
		metadataKeySSHKeys:   authKeys,
	}
	s.WindowsMetadata = map[string]string{
		metadataKeyWindowsUserdata: string(userData),
		metadataKeyWindowsSysprep:  fmt.Sprintf(winSetHostnameScript, "juju.*"),
	}
	s.Addresses = []network.Address{{
		Value: "10.0.0.1",
		Type:  network.IPv4Address,
		Scope: network.ScopeCloudLocal,
	}}
	s.Instance = s.NewInstance(c, "spam")
	s.BaseInstance = s.Instance.base
	s.InstName = s.Prefix + "machine-spam"

	s.StartInstArgs = environs.StartInstanceParams{
		InstanceConfig: instanceConfig,
		Tools:          tools,
		Constraints:    cons,
		//Placement: "",
		//DistributionGroup: nil,
	}

	s.InstanceType = allInstanceTypes[0]

	// Storage
	eUUID := s.Env.Config().UUID()
	s.BaseDisk = &google.Disk{
		Id:          1234567,
		Name:        "home-zone--c930380d-8337-4bf5-b07a-9dbb5ae771e4",
		Zone:        "home-zone",
		Status:      google.StatusReady,
		Size:        1024,
		Description: eUUID,
	}
}

func (s *BootstrapSuite) TestCannotStartInstance(c *gc.C) {
	s.PatchValue(&jujuversion.Current, coretesting.FakeVersionNumber)
	checkPlacement := "directive"
	checkCons := constraints.MustParse("mem=8G")
	env := &mockEnviron{
		storage: newStorage(s, c),
		config:  configGetter(c),
	}

	startInstance := func(
		placement string,
		cons constraints.Value,
		_ []string,
		possibleTools tools.List,
		icfg *instancecfg.InstanceConfig,
	) (instance.Instance, *instance.HardwareCharacteristics, []network.InterfaceInfo, error) {
		c.Assert(placement, gc.DeepEquals, checkPlacement)
		c.Assert(cons, gc.DeepEquals, checkCons)

		// The machine config should set its upgrade behavior based on
		// the environment config.
		expectedMcfg, err := instancecfg.NewBootstrapInstanceConfig(coretesting.FakeControllerConfig(), cons, cons, icfg.Series, "")
		c.Assert(err, jc.ErrorIsNil)
		expectedMcfg.EnableOSRefreshUpdate = env.Config().EnableOSRefreshUpdate()
		expectedMcfg.EnableOSUpgrade = env.Config().EnableOSUpgrade()
		expectedMcfg.Tags = map[string]string{
			"juju-model-uuid":      coretesting.ModelTag.Id(),
			"juju-controller-uuid": coretesting.ControllerTag.Id(),
			"juju-is-controller":   "true",
		}

		c.Assert(icfg, jc.DeepEquals, expectedMcfg)
		return nil, nil, nil, errors.Errorf("meh, not started")
	}

	env.startInstance = startInstance

	ctx := envtesting.BootstrapContext(c)
	_, err := common.Bootstrap(ctx, env, environs.BootstrapParams{
		ControllerConfig:     coretesting.FakeControllerConfig(),
		BootstrapConstraints: checkCons,
		ModelConstraints:     checkCons,
		Placement:            checkPlacement,
		AvailableTools: tools.List{
			&tools.Tools{
				Version: version.Binary{
					Number: jujuversion.Current,
					Arch:   arch.HostArch(),
					Series: series.HostSeries(),
				},
			},
		}})
	c.Assert(err, gc.ErrorMatches, "cannot start bootstrap instance: meh, not started")
}

func (s *BaseSuiteUnpatched) initInst(c *gc.C) {
	tools := []*tools.Tools{{
		Version: version.Binary{Arch: arch.AMD64, Series: "trusty"},
		URL:     "https://example.org",
	}}

	cons := constraints.Value{
	// nothing
	}

	instanceConfig, err := instancecfg.NewBootstrapInstanceConfig(cons, cons, "trusty", "")
	c.Assert(err, jc.ErrorIsNil)

	instanceConfig.Tools = tools[0]
	instanceConfig.AuthorizedKeys = s.Config.AuthorizedKeys()

	userData, err := providerinit.ComposeUserData(instanceConfig, nil, lxdRenderer{})
	c.Assert(err, jc.ErrorIsNil)

	s.Hardware = &lxdclient.InstanceHardware{
		Architecture: arch.AMD64,
		NumCores:     1,
		MemoryMB:     3750,
	}
	var archName string = arch.AMD64
	var numCores uint64 = 1
	var memoryMB uint64 = 3750
	s.HWC = &instance.HardwareCharacteristics{
		Arch:     &archName,
		CpuCores: &numCores,
		Mem:      &memoryMB,
	}

	s.Metadata = map[string]string{ // userdata
		metadataKeyIsState:   metadataValueTrue, // bootstrap
		metadataKeyCloudInit: string(userData),
	}
	s.Addresses = []network.Address{{
		Value: "10.0.0.1",
		Type:  network.IPv4Address,
		Scope: network.ScopeCloudLocal,
	}}
	s.Instance = s.NewInstance(c, "spam")
	s.RawInstance = s.Instance.raw
	s.InstName = s.Prefix + "machine-spam"

	s.StartInstArgs = environs.StartInstanceParams{
		InstanceConfig: instanceConfig,
		Tools:          tools,
		Constraints:    cons,
	}
}

func (s *BaseSuiteUnpatched) initInst(c *gc.C) {
	tools := []*tools.Tools{{
		Version: version.Binary{Arch: arch.AMD64, Series: "trusty"},
		URL:     "https://example.org",
	}}

	cons := constraints.Value{InstanceType: &allInstanceTypes[0].Name}

	instanceConfig, err := instancecfg.NewBootstrapInstanceConfig(cons, "trusty")
	c.Assert(err, jc.ErrorIsNil)

	instanceConfig.Tools = tools[0]
	instanceConfig.AuthorizedKeys = s.Config.AuthorizedKeys()

	userData, err := providerinit.ComposeUserData(instanceConfig, nil)
	c.Assert(err, jc.ErrorIsNil)
	b64UserData := base64.StdEncoding.EncodeToString([]byte(userData))

	authKeys, err := google.FormatAuthorizedKeys(instanceConfig.AuthorizedKeys, "ubuntu")
	c.Assert(err, jc.ErrorIsNil)

	s.Metadata = map[string]string{
		metadataKeyIsState:   metadataValueTrue,
		metadataKeyCloudInit: b64UserData,
		metadataKeyEncoding:  "base64",
		metadataKeySSHKeys:   authKeys,
	}
	s.Addresses = []network.Address{{
		Value: "10.0.0.1",
		Type:  network.IPv4Address,
		Scope: network.ScopeCloudLocal,
	}}
	s.Instance = s.NewInstance(c, "spam")
	s.BaseInstance = s.Instance.base
	s.InstName = s.Prefix + "machine-spam"

	s.StartInstArgs = environs.StartInstanceParams{
		InstanceConfig: instanceConfig,
		Tools:          tools,
		Constraints:    cons,
		//Placement: "",
		//DistributionGroup: nil,
	}

	s.InstanceType = allInstanceTypes[0]
}

func (s *localJujuTestSuite) testBootstrap(c *gc.C, cfg *config.Config) environs.Environ {
	ctx := envtesting.BootstrapContext(c)
	environ, err := local.Provider.PrepareForBootstrap(ctx, cfg)
	c.Assert(err, jc.ErrorIsNil)
	availableTools := coretools.List{&coretools.Tools{
		Version: version.Current,
		URL:     "http://testing.invalid/tools.tar.gz",
	}}
	_, _, finalizer, err := environ.Bootstrap(ctx, environs.BootstrapParams{
		AvailableTools: availableTools,
	})
	c.Assert(err, jc.ErrorIsNil)
	icfg, err := instancecfg.NewBootstrapInstanceConfig(constraints.Value{}, "quantal")
	c.Assert(err, jc.ErrorIsNil)
	icfg.Tools = availableTools[0]
	err = finalizer(ctx, icfg)
	c.Assert(err, jc.ErrorIsNil)
	return environ
}

func (s *environBrokerSuite) CreateStartInstanceArgs(c *gc.C) environs.StartInstanceParams {
	tools := []*tools.Tools{{
		Version: version.Binary{Arch: arch.AMD64, Series: "trusty"},
		URL:     "https://example.org",
	}}

	cons := constraints.Value{}

	instanceConfig, err := instancecfg.NewBootstrapInstanceConfig(cons, cons, "trusty", "")
	c.Assert(err, jc.ErrorIsNil)

	instanceConfig.Tools = tools[0]
	instanceConfig.AuthorizedKeys = s.Config.AuthorizedKeys()

	return environs.StartInstanceParams{
		InstanceConfig: instanceConfig,
		Tools:          tools,
		Constraints:    cons,
	}
}

//.........这里部分代码省略.........

	// Set default tools metadata source, add image metadata source,
	// then verify constraints. Providers may rely on image metadata
	// for constraint validation.
	var imageMetadata []*imagemetadata.ImageMetadata
	if args.MetadataDir != "" {
		var err error
		imageMetadata, err = setPrivateMetadataSources(environ, args.MetadataDir)
		if err != nil {
			return err
		}
	}
	if err := validateConstraints(environ, args.Constraints); err != nil {
		return err
	}

	_, supportsNetworking := environs.SupportsNetworking(environ)

	ctx.Infof("Bootstrapping environment %q", cfg.Name())
	logger.Debugf("environment %q supports service/machine networks: %v", cfg.Name(), supportsNetworking)
	disableNetworkManagement, _ := cfg.DisableNetworkManagement()
	logger.Debugf("network management by juju enabled: %v", !disableNetworkManagement)
	availableTools, err := findAvailableTools(environ, args.AgentVersion, args.Constraints.Arch, args.UploadTools)
	if errors.IsNotFound(err) {
		return errors.New(noToolsMessage)
	} else if err != nil {
		return err
	}
	if lxcMTU, ok := cfg.LXCDefaultMTU(); ok {
		logger.Debugf("using MTU %v for all created LXC containers' network interfaces", lxcMTU)
	}

	// If we're uploading, we must override agent-version;
	// if we're not uploading, we want to ensure we have an
	// agent-version set anyway, to appease FinishInstanceConfig.
	// In the latter case, setBootstrapTools will later set
	// agent-version to the correct thing.
	agentVersion := version.Current
	if args.AgentVersion != nil {
		agentVersion = *args.AgentVersion
	}
	if cfg, err = cfg.Apply(map[string]interface{}{
		"agent-version": agentVersion.String(),
	}); err != nil {
		return err
	}
	if err = environ.SetConfig(cfg); err != nil {
		return err
	}

	ctx.Infof("Starting new instance for initial state server")
	arch, series, finalizer, err := environ.Bootstrap(ctx, environs.BootstrapParams{
		Constraints:    args.Constraints,
		Placement:      args.Placement,
		AvailableTools: availableTools,
	})
	if err != nil {
		return err
	}

	matchingTools, err := availableTools.Match(coretools.Filter{
		Arch:   arch,
		Series: series,
	})
	if err != nil {
		return err
	}
	selectedTools, err := setBootstrapTools(environ, matchingTools)
	if err != nil {
		return err
	}
	if selectedTools.URL == "" {
		if !args.UploadTools {
			logger.Warningf("no prepackaged tools available")
		}
		ctx.Infof("Building tools to upload (%s)", selectedTools.Version)
		builtTools, err := sync.BuildToolsTarball(&selectedTools.Version.Number, cfg.AgentStream())
		if err != nil {
			return errors.Annotate(err, "cannot upload bootstrap tools")
		}
		defer os.RemoveAll(builtTools.Dir)
		filename := filepath.Join(builtTools.Dir, builtTools.StorageName)
		selectedTools.URL = fmt.Sprintf("file://%s", filename)
		selectedTools.Size = builtTools.Size
		selectedTools.SHA256 = builtTools.Sha256Hash
	}

	ctx.Infof("Installing Juju agent on bootstrap instance")
	instanceConfig, err := instancecfg.NewBootstrapInstanceConfig(args.Constraints, series)
	if err != nil {
		return err
	}
	instanceConfig.Tools = selectedTools
	instanceConfig.CustomImageMetadata = imageMetadata
	if err := finalizer(ctx, instanceConfig); err != nil {
		return err
	}
	ctx.Infof("Bootstrap agent installed")
	return nil
}

// BootstrapInstance creates a new instance with the series of its choice,
// constrained to those of the available tools, and
// returns the instance result, series, and a function that
// must be called to finalize the bootstrap process by transferring
// the tools and installing the initial Juju controller.
// This method is called by Bootstrap above, which implements environs.Bootstrap, but
// is also exported so that providers can manipulate the started instance.
func BootstrapInstance(ctx environs.BootstrapContext, env environs.Environ, args environs.BootstrapParams,
) (_ *environs.StartInstanceResult, selectedSeries string, _ environs.BootstrapFinalizer, err error) {
	// TODO make safe in the case of racing Bootstraps
	// If two Bootstraps are called concurrently, there's
	// no way to make sure that only one succeeds.

	// First thing, ensure we have tools otherwise there's no point.
	if args.BootstrapSeries != "" {
		selectedSeries = args.BootstrapSeries
	} else {
		selectedSeries = config.PreferredSeries(env.Config())
	}
	availableTools, err := args.AvailableTools.Match(coretools.Filter{
		Series: selectedSeries,
	})
	if err != nil {
		return nil, "", nil, err
	}

	// Filter image metadata to the selected series.
	var imageMetadata []*imagemetadata.ImageMetadata
	seriesVersion, err := series.SeriesVersion(selectedSeries)
	if err != nil {
		return nil, "", nil, errors.Trace(err)
	}
	for _, m := range args.ImageMetadata {
		if m.Version != seriesVersion {
			continue
		}
		imageMetadata = append(imageMetadata, m)
	}

	// Get the bootstrap SSH client. Do this early, so we know
	// not to bother with any of the below if we can't finish the job.
	client := ssh.DefaultClient
	if client == nil {
		// This should never happen: if we don't have OpenSSH, then
		// go.crypto/ssh should be used with an auto-generated key.
		return nil, "", nil, fmt.Errorf("no SSH client available")
	}

	publicKey, err := simplestreams.UserPublicSigningKey()
	if err != nil {
		return nil, "", nil, err
	}
	envCfg := env.Config()
	instanceConfig, err := instancecfg.NewBootstrapInstanceConfig(
		args.ControllerConfig, args.BootstrapConstraints, args.ModelConstraints, selectedSeries, publicKey,
	)
	if err != nil {
		return nil, "", nil, err
	}
	instanceConfig.EnableOSRefreshUpdate = env.Config().EnableOSRefreshUpdate()
	instanceConfig.EnableOSUpgrade = env.Config().EnableOSUpgrade()

	instanceConfig.Tags = instancecfg.InstanceTags(envCfg.UUID(), args.ControllerConfig.ControllerUUID(), envCfg, instanceConfig.Jobs)
	maybeSetBridge := func(icfg *instancecfg.InstanceConfig) {
		// If we need to override the default bridge name, do it now. When
		// args.ContainerBridgeName is empty, the default names for LXC
		// (lxcbr0) and KVM (virbr0) will be used.
		if args.ContainerBridgeName != "" {
			logger.Debugf("using %q as network bridge for all container types", args.ContainerBridgeName)
			if icfg.AgentEnvironment == nil {
				icfg.AgentEnvironment = make(map[string]string)
			}
			icfg.AgentEnvironment[agent.LxcBridge] = args.ContainerBridgeName
		}
	}
	maybeSetBridge(instanceConfig)

	cloudRegion := args.CloudName
	if args.CloudRegion != "" {
		cloudRegion += "/" + args.CloudRegion
	}
	fmt.Fprintf(ctx.GetStderr(), "Launching controller instance(s) on %s...\n", cloudRegion)
	// Print instance status reports status changes during provisioning.
	// Note the carriage returns, meaning subsequent prints are to the same
	// line of stderr, not a new line.
	instanceStatus := func(settableStatus status.Status, info string, data map[string]interface{}) error {
		// The data arg is not expected to be used in this case, but
		// print it, rather than ignore it, if we get something.
		dataString := ""
		if len(data) > 0 {
			dataString = fmt.Sprintf(" %v", data)
		}
		fmt.Fprintf(ctx.GetStderr(), " - %s%s\r", info, dataString)
		return nil
	}
	// Likely used after the final instanceStatus call to white-out the
	// current stderr line before the next use, removing any residual status
	// reporting output.
	statusCleanup := func(info string) error {
		// The leading spaces account for the leading characters
//.........这里部分代码省略.........

// BootstrapInstance creates a new instance with the series and architecture
// of its choice, constrained to those of the available tools, and
// returns the instance result, series, and a function that
// must be called to finalize the bootstrap process by transferring
// the tools and installing the initial Juju state server.
// This method is called by Bootstrap above, which implements environs.Bootstrap, but
// is also exported so that providers can manipulate the started instance.
func BootstrapInstance(ctx environs.BootstrapContext, env environs.Environ, args environs.BootstrapParams,
) (_ *environs.StartInstanceResult, series string, _ environs.BootstrapFinalizer, err error) {
	// TODO make safe in the case of racing Bootstraps
	// If two Bootstraps are called concurrently, there's
	// no way to make sure that only one succeeds.

	// First thing, ensure we have tools otherwise there's no point.
	series = config.PreferredSeries(env.Config())
	availableTools, err := args.AvailableTools.Match(coretools.Filter{Series: series})
	if err != nil {
		return nil, "", nil, err
	}

	// Get the bootstrap SSH client. Do this early, so we know
	// not to bother with any of the below if we can't finish the job.
	client := ssh.DefaultClient
	if client == nil {
		// This should never happen: if we don't have OpenSSH, then
		// go.crypto/ssh should be used with an auto-generated key.
		return nil, "", nil, fmt.Errorf("no SSH client available")
	}

	instanceConfig, err := instancecfg.NewBootstrapInstanceConfig(args.Constraints, series)
	if err != nil {
		return nil, "", nil, err
	}
	instanceConfig.EnableOSRefreshUpdate = env.Config().EnableOSRefreshUpdate()
	instanceConfig.EnableOSUpgrade = env.Config().EnableOSUpgrade()
	instanceConfig.Tags = instancecfg.InstanceTags(env.Config(), instanceConfig.Jobs)
	maybeSetBridge := func(icfg *instancecfg.InstanceConfig) {
		// If we need to override the default bridge name, do it now. When
		// args.ContainerBridgeName is empty, the default names for LXC
		// (lxcbr0) and KVM (virbr0) will be used.
		if args.ContainerBridgeName != "" {
			logger.Debugf("using %q as network bridge for all container types", args.ContainerBridgeName)
			if icfg.AgentEnvironment == nil {
				icfg.AgentEnvironment = make(map[string]string)
			}
			icfg.AgentEnvironment[agent.LxcBridge] = args.ContainerBridgeName
		}
	}
	maybeSetBridge(instanceConfig)

	fmt.Fprintln(ctx.GetStderr(), "Launching instance")
	result, err := env.StartInstance(environs.StartInstanceParams{
		Constraints:    args.Constraints,
		Tools:          availableTools,
		InstanceConfig: instanceConfig,
		Placement:      args.Placement,
	})
	if err != nil {
		return nil, "", nil, errors.Annotate(err, "cannot start bootstrap instance")
	}
	fmt.Fprintf(ctx.GetStderr(), " - %s\n", result.Instance.Id())

	finalize := func(ctx environs.BootstrapContext, icfg *instancecfg.InstanceConfig) error {
		icfg.InstanceId = result.Instance.Id()
		icfg.HardwareCharacteristics = result.Hardware
		if err := instancecfg.FinishInstanceConfig(icfg, env.Config()); err != nil {
			return err
		}
		maybeSetBridge(icfg)
		return FinishBootstrap(ctx, client, result.Instance, icfg)
	}
	return result, series, finalize, nil
}

// BootstrapInstance creates a new instance with the series and architecture
// of its choice, constrained to those of the available tools, and
// returns the instance result, series, and a function that
// must be called to finalize the bootstrap process by transferring
// the tools and installing the initial Juju controller.
// This method is called by Bootstrap above, which implements environs.Bootstrap, but
// is also exported so that providers can manipulate the started instance.
func BootstrapInstance(ctx environs.BootstrapContext, env environs.Environ, args environs.BootstrapParams,
) (_ *environs.StartInstanceResult, selectedSeries string, _ environs.BootstrapFinalizer, err error) {
	// TODO make safe in the case of racing Bootstraps
	// If two Bootstraps are called concurrently, there's
	// no way to make sure that only one succeeds.

	// First thing, ensure we have tools otherwise there's no point.
	if args.BootstrapSeries != "" {
		selectedSeries = args.BootstrapSeries
	} else {
		selectedSeries = config.PreferredSeries(env.Config())
	}
	availableTools, err := args.AvailableTools.Match(coretools.Filter{
		Series: selectedSeries,
	})
	if err != nil {
		return nil, "", nil, err
	}

	// Filter image metadata to the selected series.
	var imageMetadata []*imagemetadata.ImageMetadata
	seriesVersion, err := series.SeriesVersion(selectedSeries)
	if err != nil {
		return nil, "", nil, errors.Trace(err)
	}
	for _, m := range args.ImageMetadata {
		if m.Version != seriesVersion {
			continue
		}
		imageMetadata = append(imageMetadata, m)
	}

	// Get the bootstrap SSH client. Do this early, so we know
	// not to bother with any of the below if we can't finish the job.
	client := ssh.DefaultClient
	if client == nil {
		// This should never happen: if we don't have OpenSSH, then
		// go.crypto/ssh should be used with an auto-generated key.
		return nil, "", nil, fmt.Errorf("no SSH client available")
	}

	publicKey, err := simplestreams.UserPublicSigningKey()
	if err != nil {
		return nil, "", nil, err
	}
	instanceConfig, err := instancecfg.NewBootstrapInstanceConfig(
		args.BootstrapConstraints, args.ModelConstraints, selectedSeries, publicKey,
	)
	if err != nil {
		return nil, "", nil, err
	}
	instanceConfig.EnableOSRefreshUpdate = env.Config().EnableOSRefreshUpdate()
	instanceConfig.EnableOSUpgrade = env.Config().EnableOSUpgrade()
	instanceConfig.Tags = instancecfg.InstanceTags(env.Config(), instanceConfig.Jobs)
	maybeSetBridge := func(icfg *instancecfg.InstanceConfig) {
		// If we need to override the default bridge name, do it now. When
		// args.ContainerBridgeName is empty, the default names for LXC
		// (lxcbr0) and KVM (virbr0) will be used.
		if args.ContainerBridgeName != "" {
			logger.Debugf("using %q as network bridge for all container types", args.ContainerBridgeName)
			if icfg.AgentEnvironment == nil {
				icfg.AgentEnvironment = make(map[string]string)
			}
			icfg.AgentEnvironment[agent.LxcBridge] = args.ContainerBridgeName
		}
	}
	maybeSetBridge(instanceConfig)

	fmt.Fprintln(ctx.GetStderr(), "Launching instance")
	instanceStatus := func(settableStatus status.Status, info string, data map[string]interface{}) error {
		fmt.Fprintf(ctx.GetStderr(), "%s      \r", info)
		return nil
	}
	result, err := env.StartInstance(environs.StartInstanceParams{
		Constraints:    args.BootstrapConstraints,
		Tools:          availableTools,
		InstanceConfig: instanceConfig,
		Placement:      args.Placement,
		ImageMetadata:  imageMetadata,
		StatusCallback: instanceStatus,
	})
	if err != nil {
		return nil, "", nil, errors.Annotate(err, "cannot start bootstrap instance")
	}
	fmt.Fprintf(ctx.GetStderr(), " - %s\n", result.Instance.Id())

	finalize := func(ctx environs.BootstrapContext, icfg *instancecfg.InstanceConfig) error {
		icfg.InstanceId = result.Instance.Id()
		icfg.HardwareCharacteristics = result.Hardware
		envConfig := env.Config()
		if result.Config != nil {
			updated, err := envConfig.Apply(result.Config.UnknownAttrs())
			if err != nil {
//.........这里部分代码省略.........

//.........这里部分代码省略.........
		defer os.RemoveAll(builtTools.Dir)
		for i, tool := range availableTools {
			if tool.URL != "" {
				continue
			}
			filename := filepath.Join(builtTools.Dir, builtTools.StorageName)
			tool.URL = fmt.Sprintf("file://%s", filename)
			tool.Size = builtTools.Size
			tool.SHA256 = builtTools.Sha256Hash
			availableTools[i] = tool
		}
	}
	if len(availableTools) == 0 {
		return errors.New(noToolsMessage)
	}

	// If we're uploading, we must override agent-version;
	// if we're not uploading, we want to ensure we have an
	// agent-version set anyway, to appease FinishInstanceConfig.
	// In the latter case, setBootstrapTools will later set
	// agent-version to the correct thing.
	agentVersion := jujuversion.Current
	if args.AgentVersion != nil {
		agentVersion = *args.AgentVersion
	}
	if cfg, err = cfg.Apply(map[string]interface{}{
		"agent-version": agentVersion.String(),
	}); err != nil {
		return err
	}
	if err = environ.SetConfig(cfg); err != nil {
		return err
	}

	ctx.Verbosef("Starting new instance for initial controller")

	result, err := environ.Bootstrap(ctx, environs.BootstrapParams{
		CloudName:            args.CloudName,
		CloudRegion:          args.CloudRegion,
		ControllerConfig:     args.ControllerConfig,
		ModelConstraints:     args.ModelConstraints,
		BootstrapConstraints: bootstrapConstraints,
		BootstrapSeries:      args.BootstrapSeries,
		Placement:            args.Placement,
		AvailableTools:       availableTools,
		ImageMetadata:        imageMetadata,
	})
	if err != nil {
		return err
	}

	matchingTools, err := availableTools.Match(coretools.Filter{
		Arch:   result.Arch,
		Series: result.Series,
	})
	if err != nil {
		return err
	}
	selectedToolsList, err := getBootstrapToolsVersion(matchingTools)
	if err != nil {
		return err
	}
	// We set agent-version to the newest version, so the agent will immediately upgrade itself.
	// Note that this only is relevant if a specific agent version has not been requested, since
	// in that case the specific version will be the only version available.
	newestVersion, _ := matchingTools.Newest()
	if err := setBootstrapToolsVersion(environ, newestVersion); err != nil {
		return err
	}

	logger.Infof("Installing Juju agent on bootstrap instance")
	publicKey, err := userPublicSigningKey()
	if err != nil {
		return err
	}
	instanceConfig, err := instancecfg.NewBootstrapInstanceConfig(
		args.ControllerConfig,
		bootstrapConstraints,
		args.ModelConstraints,
		result.Series,
		publicKey,
	)
	if err != nil {
		return err
	}
	if err := instanceConfig.SetTools(selectedToolsList); err != nil {
		return errors.Trace(err)
	}
	// Make sure we have the most recent environ config as the specified
	// tools version has been updated there.
	cfg = environ.Config()
	if err := finalizeInstanceBootstrapConfig(ctx, instanceConfig, args, cfg, customImageMetadata); err != nil {
		return errors.Annotate(err, "finalizing bootstrap instance config")
	}
	if err := result.Finalize(ctx, instanceConfig, args.DialOpts); err != nil {
		return err
	}
	ctx.Infof("Bootstrap agent now started")
	return nil
}