func ConfigureMachine(ctx environs.BootstrapContext, client ssh.Client, host string, machineConfig *cloudinit.MachineConfig) error {
	// Bootstrap is synchronous, and will spawn a subprocess
	// to complete the procedure. If the user hits Ctrl-C,
	// SIGINT is sent to the foreground process attached to
	// the terminal, which will be the ssh subprocess at this
	// point. For that reason, we do not call StopInterruptNotify
	// until this function completes.
	cloudcfg := coreCloudinit.New()
	cloudcfg.SetAptUpdate(machineConfig.EnableOSRefreshUpdate)
	cloudcfg.SetAptUpgrade(machineConfig.EnableOSUpgrade)

	udata, err := cloudinit.NewUserdataConfig(machineConfig, cloudcfg)
	if err != nil {
		return err
	}
	if err := udata.ConfigureJuju(); err != nil {
		return err
	}
	configScript, err := sshinit.ConfigureScript(cloudcfg)
	if err != nil {
		return err
	}
	script := shell.DumpFileOnErrorScript(machineConfig.CloudInitOutputLog) + configScript
	return sshinit.RunConfigureScript(script, sshinit.ConfigureParams{
		Host:           "[email protected]" + host,
		Client:         client,
		Config:         cloudcfg,
		ProgressWriter: ctx.GetStderr(),
	})
}

// PrepareForBootstrap is specified in the EnvironProvider interface.
func (prov *azureEnvironProvider) PrepareForBootstrap(ctx environs.BootstrapContext, cfg *config.Config) (environs.Environ, error) {
	// Ensure that internal configuration is not specified, and then set
	// what we can now. We only need to do this during bootstrap. Validate
	// will check for changes later.
	unknownAttrs := cfg.UnknownAttrs()
	for _, key := range internalConfigAttributes {
		if _, ok := unknownAttrs[key]; ok {
			return nil, errors.Errorf(`internal config %q must not be specified`, key)
		}
	}

	// Record the UUID that will be used for the controller environment.
	cfg, err := cfg.Apply(map[string]interface{}{
		configAttrControllerResourceGroup: resourceGroupName(cfg),
	})
	if err != nil {
		return nil, errors.Annotate(err, "recording controller-resource-group")
	}

	env, err := prov.Open(cfg)
	if err != nil {
		return nil, errors.Trace(err)
	}
	if ctx.ShouldVerifyCredentials() {
		if err := verifyCredentials(env.(*azureEnviron)); err != nil {
			return nil, errors.Trace(err)
		}
	}
	return env, nil
}

// Bootstrap is a common implementation of the Bootstrap method defined on
// environs.Environ; we strongly recommend that this implementation be used
// when writing a new provider.
func Bootstrap(ctx environs.BootstrapContext, env environs.Environ, args environs.BootstrapParams) (arch, 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.

	var inst instance.Instance
	defer func() { handleBootstrapError(err, ctx, inst, env) }()

	// 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, 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, fmt.Errorf("no SSH client available")
	}

	machineConfig, err := environs.NewBootstrapMachineConfig(args.Constraints, series)
	if err != nil {
		return "", "", nil, err
	}
	machineConfig.EnableOSRefreshUpdate = env.Config().EnableOSRefreshUpdate()
	machineConfig.EnableOSUpgrade = env.Config().EnableOSUpgrade()

	fmt.Fprintln(ctx.GetStderr(), "Launching instance")
	inst, hw, _, err := env.StartInstance(environs.StartInstanceParams{
		Constraints:   args.Constraints,
		Tools:         availableTools,
		MachineConfig: machineConfig,
		Placement:     args.Placement,
	})
	if err != nil {
		return "", "", nil, fmt.Errorf("cannot start bootstrap instance: %v", err)
	}
	fmt.Fprintf(ctx.GetStderr(), " - %s\n", inst.Id())

	err = SaveState(env.Storage(), &BootstrapState{
		StateInstances: []instance.Id{inst.Id()},
	})
	if err != nil {
		return "", "", nil, fmt.Errorf("cannot save state: %v", err)
	}
	finalize := func(ctx environs.BootstrapContext, mcfg *cloudinit.MachineConfig) error {
		mcfg.InstanceId = inst.Id()
		mcfg.HardwareCharacteristics = hw
		if err := environs.FinishMachineConfig(mcfg, env.Config()); err != nil {
			return err
		}
		return FinishBootstrap(ctx, client, inst, mcfg)
	}
	return *hw.Arch, series, finalize, nil
}

// PrepareForBootstrap implements environs.Environ.
func (env *environ) PrepareForBootstrap(ctx environs.BootstrapContext) error {
	if ctx.ShouldVerifyCredentials() {
		if err := env.gce.VerifyCredentials(); err != nil {
			return errors.Trace(err)
		}
	}
	return nil
}

// Bootstrap is a common implementation of the Bootstrap method defined on
// environs.Environ; we strongly recommend that this implementation be used
// when writing a new provider.
func Bootstrap(ctx environs.BootstrapContext, env environs.Environ, args environs.BootstrapParams) (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.

	var inst instance.Instance
	defer func() { handleBootstrapError(err, ctx, inst, env) }()

	network.InitializeFromConfig(env.Config())

	// First thing, ensure we have tools otherwise there's no point.
	selectedTools, err := EnsureBootstrapTools(ctx, env, config.PreferredSeries(env.Config()), args.Constraints.Arch)
	if err != nil {
		return 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 fmt.Errorf("no SSH client available")
	}

	privateKey, err := GenerateSystemSSHKey(env)
	if err != nil {
		return err
	}
	machineConfig := environs.NewBootstrapMachineConfig(privateKey)

	fmt.Fprintln(ctx.GetStderr(), "Launching instance")
	inst, hw, _, err := env.StartInstance(environs.StartInstanceParams{
		Constraints:   args.Constraints,
		Tools:         selectedTools,
		MachineConfig: machineConfig,
		Placement:     args.Placement,
	})
	if err != nil {
		return fmt.Errorf("cannot start bootstrap instance: %v", err)
	}
	fmt.Fprintf(ctx.GetStderr(), " - %s\n", inst.Id())
	machineConfig.InstanceId = inst.Id()
	machineConfig.HardwareCharacteristics = hw

	err = bootstrap.SaveState(
		env.Storage(),
		&bootstrap.BootstrapState{
			StateInstances: []instance.Id{inst.Id()},
		})
	if err != nil {
		return fmt.Errorf("cannot save state: %v", err)
	}
	return FinishBootstrap(ctx, client, inst, machineConfig)
}

// PrepareForBootstrap is specified in the EnvironProvider interface.
func (p maasEnvironProvider) PrepareForBootstrap(ctx environs.BootstrapContext, cfg *config.Config) (environs.Environ, error) {
	env, err := p.Open(cfg)
	if err != nil {
		return nil, err
	}
	if ctx.ShouldVerifyCredentials() {
		if err := verifyCredentials(env.(*maasEnviron)); err != nil {
			return nil, err
		}
	}
	return env, nil
}

// PrepareForBootstrap is specified in the EnvironProvider interface.
func (p joyentProvider) PrepareForBootstrap(ctx environs.BootstrapContext, cfg *config.Config) (environs.Environ, error) {
	e, err := p.Open(cfg)
	if err != nil {
		return nil, errors.Trace(err)
	}
	if ctx.ShouldVerifyCredentials() {
		if err := verifyCredentials(e.(*joyentEnviron)); err != nil {
			return nil, errors.Trace(err)
		}
	}
	return e, nil
}

func (p environProvider) PrepareForBootstrap(ctx environs.BootstrapContext, cfg *config.Config) (environs.Environ, error) {
	cfg, err := p.PrepareForCreateEnvironment(cfg)
	if err != nil {
		return nil, err
	}
	e, err := p.Open(cfg)
	if err != nil {
		return nil, err
	}
	if ctx.ShouldVerifyCredentials() {
		if err := verifyCredentials(e.(*environ)); err != nil {
			return nil, err
		}
	}
	return e, nil
}

// PrepareForBootstrap is specified in the EnvironProvider interface.
func (prov azureEnvironProvider) PrepareForBootstrap(ctx environs.BootstrapContext, cfg *config.Config) (environs.Environ, error) {
	cfg, err := prov.PrepareForCreateEnvironment(cfg)
	if err != nil {
		return nil, errors.Trace(err)
	}
	env, err := prov.Open(cfg)
	if err != nil {
		return nil, errors.Trace(err)
	}
	if ctx.ShouldVerifyCredentials() {
		if err := verifyCredentials(env.(*azureEnviron)); err != nil {
			return nil, errors.Trace(err)
		}
	}
	return env, nil
}

func validateBootstrapVPC(apiClient vpcAPIClient, region, vpcID string, forceVPCID bool, ctx environs.BootstrapContext) error {
	if vpcID == vpcIDNone {
		ctx.Infof("Using EC2-classic features or default VPC in region %q", region)
	}
	if !isVPCIDSet(vpcID) {
		return nil
	}

	err := validateVPC(apiClient, vpcID)
	switch {
	case isVPCNotUsableError(err):
		// VPC missing or has no subnets at all.
		return errors.Annotate(err, vpcNotUsableForBootstrapErrorPrefix)
	case isVPCNotRecommendedError(err):
		// VPC does not meet minumum validation criteria.
		if !forceVPCID {
			return errors.Annotatef(err, vpcNotRecommendedErrorPrefix, vpcID)
		}
		ctx.Infof(vpcNotRecommendedButForcedWarning)
	case err != nil:
		// Anything else unexpected while validating the VPC.
		return errors.Annotate(err, cannotValidateVPCErrorPrefix)
	}

	ctx.Infof("Using VPC %q in region %q", vpcID, region)

	return nil
}

// UploadTools uploads tools for the specified series and any other relevant series to
// the environment storage, after which it sets the agent-version. If forceVersion is true,
// we allow uploading even when the agent-version is already set in the environment.
func UploadTools(ctx environs.BootstrapContext, env environs.Environ, toolsArch *string, forceVersion bool, bootstrapSeries ...string) error {
	logger.Infof("checking that upload is possible")
	// Check the series are valid.
	for _, series := range bootstrapSeries {
		if _, err := ubuntu.SeriesVersion(series); err != nil {
			return err
		}
	}
	// See that we are allowed to upload the tools.
	if err := validateUploadAllowed(env, toolsArch, forceVersion); err != nil {
		return err
	}

	// Make storage interruptible.
	interrupted := make(chan os.Signal, 1)
	interruptStorage := make(chan struct{})
	ctx.InterruptNotify(interrupted)
	defer ctx.StopInterruptNotify(interrupted)
	defer close(interrupted)
	go func() {
		defer close(interruptStorage) // closing interrupts all uploads
		if _, ok := <-interrupted; ok {
			ctx.Infof("cancelling tools upload")
		}
	}()
	stor := newInterruptibleStorage(env.Storage(), interruptStorage)

	cfg := env.Config()
	explicitVersion := uploadVersion(version.Current.Number, nil)
	uploadSeries := SeriesToUpload(cfg, bootstrapSeries)
	ctx.Infof("uploading tools for series %s", uploadSeries)
	tools, err := sync.Upload(stor, &explicitVersion, uploadSeries...)
	if err != nil {
		return err
	}
	cfg, err = cfg.Apply(map[string]interface{}{
		"agent-version": tools.Version.Number.String(),
	})
	if err == nil {
		err = env.SetConfig(cfg)
	}
	if err != nil {
		return fmt.Errorf("failed to update environment configuration: %v", err)
	}
	return nil
}

// Bootstrap bootstraps the given environment. The supplied constraints are
// used to provision the instance, and are also set within the bootstrapped
// environment.
func Bootstrap(ctx environs.BootstrapContext, environ environs.Environ, args BootstrapParams) error {
	cfg := environ.Config()
	network.InitializeFromConfig(cfg)
	if secret := cfg.AdminSecret(); secret == "" {
		return errors.Errorf("environment configuration has no admin-secret")
	}
	if authKeys := ssh.SplitAuthorisedKeys(cfg.AuthorizedKeys()); len(authKeys) == 0 {
		// Apparently this can never happen, so it's not tested. But, one day,
		// Config will act differently (it's pretty crazy that, AFAICT, the
		// authorized-keys are optional config settings... but it's impossible
		// to actually *create* a config without them)... and when it does,
		// we'll be here to catch this problem early.
		return errors.Errorf("environment configuration has no authorized-keys")
	}
	if _, hasCACert := cfg.CACert(); !hasCACert {
		return errors.Errorf("environment configuration has no ca-cert")
	}
	if _, hasCAKey := cfg.CAPrivateKey(); !hasCAKey {
		return errors.Errorf("environment configuration has no ca-private-key")
	}

	// 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())
//.........这里部分代码省略.........

// 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.........

// Bootstrap bootstraps the given environment. The supplied constraints are
// used to provision the instance, and are also set within the bootstrapped
// environment.
func Bootstrap(ctx environs.BootstrapContext, environ environs.Environ, args BootstrapParams) error {
	if err := args.Validate(); err != nil {
		return errors.Annotate(err, "validating bootstrap parameters")
	}

	cfg := environ.Config()
	if authKeys := ssh.SplitAuthorisedKeys(cfg.AuthorizedKeys()); len(authKeys) == 0 {
		// Apparently this can never happen, so it's not tested. But, one day,
		// Config will act differently (it's pretty crazy that, AFAICT, the
		// authorized-keys are optional config settings... but it's impossible
		// to actually *create* a config without them)... and when it does,
		// we'll be here to catch this problem early.
		return errors.Errorf("model configuration has no authorized-keys")
	}

	_, supportsNetworking := environs.SupportsNetworking(environ)
	logger.Debugf("model %q supports service/machine networks: %v", cfg.Name(), supportsNetworking)
	disableNetworkManagement, _ := cfg.DisableNetworkManagement()
	logger.Debugf("network management by juju enabled: %v", !disableNetworkManagement)

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

	var bootstrapSeries *string
	if args.BootstrapSeries != "" {
		bootstrapSeries = &args.BootstrapSeries
	}

	var bootstrapArchForImageSearch string
	if args.BootstrapConstraints.Arch != nil {
		bootstrapArchForImageSearch = *args.BootstrapConstraints.Arch
	} else if args.ModelConstraints.Arch != nil {
		bootstrapArchForImageSearch = *args.ModelConstraints.Arch
	} else {
		bootstrapArchForImageSearch = arch.HostArch()
		// We no longer support i386.
		if bootstrapArchForImageSearch == arch.I386 {
			bootstrapArchForImageSearch = arch.AMD64
		}
	}

	ctx.Verbosef("Loading image metadata")
	imageMetadata, err := bootstrapImageMetadata(environ,
		bootstrapSeries,
		bootstrapArchForImageSearch,
		args.BootstrapImage,
		&customImageMetadata,
	)
	if err != nil {
		return errors.Trace(err)
	}

	// We want to determine a list of valid architectures for which to pick tools and images.
	// This includes architectures from custom and other available image metadata.
	architectures := set.NewStrings()
	if len(customImageMetadata) > 0 {
		for _, customMetadata := range customImageMetadata {
			architectures.Add(customMetadata.Arch)
		}
	}
	if len(imageMetadata) > 0 {
		for _, iMetadata := range imageMetadata {
			architectures.Add(iMetadata.Arch)
		}
	}

	constraintsValidator, err := environ.ConstraintsValidator()
	if err != nil {
		return err
	}
	constraintsValidator.UpdateVocabulary(constraints.Arch, architectures.SortedValues())

	bootstrapConstraints, err := constraintsValidator.Merge(
		args.ModelConstraints, args.BootstrapConstraints,
	)
	if err != nil {
		return errors.Trace(err)
	}

	// The arch we use to find tools isn't the boostrapConstraints arch.
	// We copy the constraints arch to a separate variable and
	// update it from the host arch if not specified.
	// (axw) This is still not quite right:
	// For e.g. if there is a MAAS with only ARM64 machines,
	// on an AMD64 client, we're going to look for only AMD64 tools,
	// limiting what the provider can bootstrap anyway.
	var bootstrapArch string
	if bootstrapConstraints.Arch != nil {
//.........这里部分代码省略.........

func finalizeInstanceBootstrapConfig(
	ctx environs.BootstrapContext,
	icfg *instancecfg.InstanceConfig,
	args BootstrapParams,
	cfg *config.Config,
	customImageMetadata []*imagemetadata.ImageMetadata,
) error {
	if icfg.APIInfo != nil || icfg.Controller.MongoInfo != nil {
		return errors.New("machine configuration already has api/state info")
	}
	controllerCfg := icfg.Controller.Config
	caCert, hasCACert := controllerCfg.CACert()
	if !hasCACert {
		return errors.New("controller configuration has no ca-cert")
	}
	icfg.APIInfo = &api.Info{
		Password: args.AdminSecret,
		CACert:   caCert,
		ModelTag: names.NewModelTag(cfg.UUID()),
	}
	icfg.Controller.MongoInfo = &mongo.MongoInfo{
		Password: args.AdminSecret,
		Info:     mongo.Info{CACert: caCert},
	}

	// These really are directly relevant to running a controller.
	// Initially, generate a controller certificate with no host IP
	// addresses in the SAN field. Once the controller is up and the
	// NIC addresses become known, the certificate can be regenerated.
	cert, key, err := controller.GenerateControllerCertAndKey(caCert, args.CAPrivateKey, nil)
	if err != nil {
		return errors.Annotate(err, "cannot generate controller certificate")
	}
	icfg.Bootstrap.StateServingInfo = params.StateServingInfo{
		StatePort:    controllerCfg.StatePort(),
		APIPort:      controllerCfg.APIPort(),
		Cert:         string(cert),
		PrivateKey:   string(key),
		CAPrivateKey: args.CAPrivateKey,
	}
	if _, ok := cfg.AgentVersion(); !ok {
		return errors.New("controller model configuration has no agent-version")
	}

	icfg.Bootstrap.ControllerModelConfig = cfg
	icfg.Bootstrap.CustomImageMetadata = customImageMetadata
	icfg.Bootstrap.ControllerCloudName = args.CloudName
	icfg.Bootstrap.ControllerCloud = args.Cloud
	icfg.Bootstrap.ControllerCloudRegion = args.CloudRegion
	icfg.Bootstrap.ControllerCloudCredential = args.CloudCredential
	icfg.Bootstrap.ControllerCloudCredentialName = args.CloudCredentialName
	icfg.Bootstrap.ControllerConfig = args.ControllerConfig
	icfg.Bootstrap.ControllerInheritedConfig = args.ControllerInheritedConfig
	icfg.Bootstrap.RegionInheritedConfig = args.Cloud.RegionConfig
	icfg.Bootstrap.HostedModelConfig = args.HostedModelConfig
	icfg.Bootstrap.Timeout = args.DialOpts.Timeout
	icfg.Bootstrap.GUI = guiArchive(args.GUIDataSourceBaseURL, func(msg string) {
		ctx.Infof(msg)
	})
	return 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 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.........

// Bootstrap bootstraps the given environment. The supplied constraints are
// used to provision the instance, and are also set within the bootstrapped
// environment.
func Bootstrap(ctx environs.BootstrapContext, environ environs.Environ, args BootstrapParams) error {
	cfg := environ.Config()
	network.InitializeFromConfig(cfg)
	if secret := cfg.AdminSecret(); secret == "" {
		return errors.Errorf("environment configuration has no admin-secret")
	}
	if authKeys := ssh.SplitAuthorisedKeys(cfg.AuthorizedKeys()); len(authKeys) == 0 {
		// Apparently this can never happen, so it's not tested. But, one day,
		// Config will act differently (it's pretty crazy that, AFAICT, the
		// authorized-keys are optional config settings... but it's impossible
		// to actually *create* a config without them)... and when it does,
		// we'll be here to catch this problem early.
		return errors.Errorf("environment configuration has no authorized-keys")
	}
	if _, hasCACert := cfg.CACert(); !hasCACert {
		return errors.Errorf("environment configuration has no ca-cert")
	}
	if _, hasCAKey := cfg.CAPrivateKey(); !hasCAKey {
		return errors.Errorf("environment configuration has no ca-private-key")
	}

	// Write out the bootstrap-init file, and confirm storage is writeable.
	if err := environsVerifyStorage(environ.Storage()); err != nil {
		return err
	}

	ctx.Infof("Bootstrapping environment %q", cfg.Name())
	logger.Debugf("environment %q supports service/machine networks: %v", cfg.Name(), environ.SupportNetworks())
	disableNetworkManagement, _ := cfg.DisableNetworkManagement()
	logger.Debugf("network management by juju enabled: %v", disableNetworkManagement)
	availableTools, err := findAvailableTools(environ, args.Constraints.Arch, args.UploadTools)
	if errors.IsNotFound(err) {
		return errors.New(noToolsMessage)
	} else if err != nil {
		return err
	}

	// 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 FinishMachineConfig.
	// In the latter case, setBootstrapTools will later set
	// agent-version to the correct thing.
	if cfg, err = cfg.Apply(map[string]interface{}{
		"agent-version": version.Current.Number.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)
		if err != nil {
			return errors.Annotate(err, "cannot upload bootstrap tools")
		}
		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")
	machineConfig, err := environs.NewBootstrapMachineConfig(args.Constraints, series)
	if err != nil {
		return err
	}
	machineConfig.Tools = selectedTools
	if err := finalizer(ctx, machineConfig); err != nil {
		return err
	}
	ctx.Infof("Bootstrap complete")
//.........这里部分代码省略.........

func ensureBootstrapUbuntuUser(ctx environs.BootstrapContext, cfg *environConfig) error {
	err := initUbuntuUser(cfg.bootstrapHost(), cfg.bootstrapUser(), cfg.AuthorizedKeys(), ctx.GetStdin(), ctx.GetStdout())
	if err != nil {
		logger.Errorf("initializing ubuntu user: %v", err)
		return err
	}
	logger.Infof("initialized ubuntu user")
	return nil
}