func (s *InstanceSuite) TestParseContainerType(c *gc.C) {
	ctype, err := instance.ParseContainerType("lxc")
	c.Assert(err, jc.ErrorIsNil)
	c.Assert(ctype, gc.Equals, instance.LXC)

	ctype, err = instance.ParseContainerType("kvm")
	c.Assert(err, jc.ErrorIsNil)
	c.Assert(ctype, gc.Equals, instance.KVM)

	_, err = instance.ParseContainerType("none")
	c.Assert(err, gc.ErrorMatches, `invalid container type "none"`)

	_, err = instance.ParseContainerType("omg")
	c.Assert(err, gc.ErrorMatches, `invalid container type "omg"`)
}

// makePlacement makes a placement directive for the given machineIdSpec.
func makePlacement(machineIdSpec string) ([]*instance.Placement, error) {
	if machineIdSpec == "" {
		return nil, nil
	}
	mid := machineIdSpec
	scope := instance.MachineScope
	var containerType instance.ContainerType
	specParts := strings.SplitN(machineIdSpec, ":", 2)
	if len(specParts) > 1 {
		firstPart := specParts[0]
		var err error
		if containerType, err = instance.ParseContainerType(firstPart); err == nil {
			mid = specParts[1]
			scope = string(containerType)
		}
	}
	if !names.IsValidMachine(mid) {
		return nil, errors.Errorf("invalid force machine id %q", mid)
	}
	return []*instance.Placement{
		{
			Scope:     scope,
			Directive: mid,
		},
	}, nil
}

// AddUnits starts n units of the given service and allocates machines
// to them as necessary.
func AddUnits(st *state.State, svc *state.Service, n int, machineIdSpec string) ([]*state.Unit, error) {
	if machineIdSpec != "" && n != 1 {
		return nil, errors.Errorf("cannot add multiple units of service %q to a single machine", svc.Name())
	}
	var placement []*instance.Placement
	if machineIdSpec != "" {
		mid := machineIdSpec
		scope := instance.MachineScope
		var containerType instance.ContainerType
		specParts := strings.SplitN(machineIdSpec, ":", 2)
		if len(specParts) > 1 {
			firstPart := specParts[0]
			var err error
			if containerType, err = instance.ParseContainerType(firstPart); err == nil {
				mid = specParts[1]
				scope = string(containerType)
			}
		}
		if !names.IsValidMachine(mid) {
			return nil, fmt.Errorf("invalid force machine id %q", mid)
		}
		placement = []*instance.Placement{
			{
				Scope:     scope,
				Directive: mid,
			},
		}
	}
	return AddUnitsWithPlacement(st, svc, n, placement)
}

func addMachineForUnit(st *state.State, unit *state.Unit, placement *instance.Placement, networks []string) (*state.Machine, error) {
	unitCons, err := unit.Constraints()
	if err != nil {
		return nil, err
	}
	var containerType instance.ContainerType
	var mid, placementDirective string
	// Extract container type and parent from container placement directives.
	if containerType, err = instance.ParseContainerType(placement.Scope); err == nil {
		mid = placement.Directive
	} else {
		switch placement.Scope {
		case st.EnvironUUID():
			placementDirective = placement.Directive
		case instance.MachineScope:
			mid = placement.Directive
		default:
			return nil, errors.Errorf("invalid environment UUID %q", placement.Scope)
		}
	}

	// Create any new machine marked as dirty so that
	// nothing else will grab it before we assign the unit to it.

	// If a container is to be used, create it.
	if containerType != "" {
		template := state.MachineTemplate{
			Series:            unit.Series(),
			Jobs:              []state.MachineJob{state.JobHostUnits},
			Dirty:             true,
			Constraints:       *unitCons,
			RequestedNetworks: networks,
		}
		return st.AddMachineInsideMachine(template, mid, containerType)
	}
	// If a placement directive is to be used, do that here.
	if placementDirective != "" {
		template := state.MachineTemplate{
			Series:            unit.Series(),
			Jobs:              []state.MachineJob{state.JobHostUnits},
			Dirty:             true,
			Constraints:       *unitCons,
			RequestedNetworks: networks,
			Placement:         placementDirective,
		}
		return st.AddOneMachine(template)
	}

	// Otherwise use an existing machine.
	return st.Machine(mid)
}

func (c *Client) addOneMachine(p params.AddMachineParams) (*state.Machine, error) {
	if p.ParentId != "" && p.ContainerType == "" {
		return nil, fmt.Errorf("parent machine specified without container type")
	}
	if p.ContainerType != "" && p.Placement != nil {
		return nil, fmt.Errorf("container type and placement are mutually exclusive")
	}
	if p.Placement != nil {
		// Extract container type and parent from container placement directives.
		containerType, err := instance.ParseContainerType(p.Placement.Scope)
		if err == nil {
			p.ContainerType = containerType
			p.ParentId = p.Placement.Directive
			p.Placement = nil
		}
	}

	if p.ContainerType != "" || p.Placement != nil {
		// Guard against dubious client by making sure that
		// the following attributes can only be set when we're
		// not using placement.
		p.InstanceId = ""
		p.Nonce = ""
		p.HardwareCharacteristics = instance.HardwareCharacteristics{}
		p.Addrs = nil
	}

	if p.Series == "" {
		conf, err := c.api.state.EnvironConfig()
		if err != nil {
			return nil, err
		}
		p.Series = config.PreferredSeries(conf)
	}

	var placementDirective string
	if p.Placement != nil {
		env, err := c.api.state.Environment()
		if err != nil {
			return nil, err
		}
		// For 1.21 we should support both UUID and name, and with 1.22
		// just support UUID
		if p.Placement.Scope != env.Name() && p.Placement.Scope != env.UUID() {
			return nil, fmt.Errorf("invalid environment name %q", p.Placement.Scope)
		}
		placementDirective = p.Placement.Directive
	}

	jobs, err := common.StateJobs(p.Jobs)
	if err != nil {
		return nil, err
	}
	template := state.MachineTemplate{
		Series:      p.Series,
		Constraints: p.Constraints,
		InstanceId:  p.InstanceId,
		Jobs:        jobs,
		Nonce:       p.Nonce,
		HardwareCharacteristics: p.HardwareCharacteristics,
		Addresses:               params.NetworkAddresses(p.Addrs),
		Placement:               placementDirective,
	}
	if p.ContainerType == "" {
		return c.api.state.AddOneMachine(template)
	}
	if p.ParentId != "" {
		return c.api.state.AddMachineInsideMachine(template, p.ParentId, p.ContainerType)
	}
	return c.api.state.AddMachineInsideNewMachine(template, template, p.ContainerType)
}

// addMachine creates a new top-level machine or container in the environment.
func (h *bundleHandler) addMachine(id string, p bundlechanges.AddMachineParams) error {
	services := h.servicesForMachineChange(id)
	// Note that we always have at least one service that justifies the
	// creation of this machine.
	msg := services[0] + " unit"
	svcLen := len(services)
	if svcLen != 1 {
		msg = strings.Join(services[:svcLen-1], ", ") + " and " + services[svcLen-1] + " units"
	}
	// Check whether the desired number of units already exist in the
	// environment, in which case avoid adding other machines to host those
	// service units.
	machine := h.chooseMachine(services...)
	if machine != "" {
		h.results[id] = machine
		notify := make([]string, 0, svcLen)
		for _, service := range services {
			if !h.ignoredMachines[service] {
				h.ignoredMachines[service] = true
				notify = append(notify, service)
			}
		}
		svcLen = len(notify)
		switch svcLen {
		case 0:
			return nil
		case 1:
			msg = notify[0]
		default:
			msg = strings.Join(notify[:svcLen-1], ", ") + " and " + notify[svcLen-1]
		}
		h.log.Infof("avoid creating other machines to host %s units", msg)
		return nil
	}
	cons, err := constraints.Parse(p.Constraints)
	if err != nil {
		// This should never happen, as the bundle is already verified.
		return errors.Annotate(err, "invalid constraints for machine")
	}
	machineParams := params.AddMachineParams{
		Constraints: cons,
		Series:      p.Series,
		Jobs:        []multiwatcher.MachineJob{multiwatcher.JobHostUnits},
	}
	if p.ContainerType != "" {
		containerType, err := instance.ParseContainerType(p.ContainerType)
		if err != nil {
			return errors.Annotatef(err, "cannot create machine for holding %s", msg)
		}
		machineParams.ContainerType = containerType
		if p.ParentId != "" {
			machineParams.ParentId, err = h.resolveMachine(p.ParentId)
			if err != nil {
				return errors.Annotatef(err, "cannot retrieve parent placement for %s", msg)
			}
		}
	}
	r, err := h.client.AddMachines([]params.AddMachineParams{machineParams})
	if err != nil {
		return errors.Annotatef(err, "cannot create machine for holding %s", msg)
	}
	if r[0].Error != nil {
		return errors.Annotatef(r[0].Error, "cannot create machine for holding %s", msg)
	}
	machine = r[0].Machine
	if p.ContainerType == "" {
		h.log.Infof("created new machine %s for holding %s", machine, msg)
	} else if p.ParentId == "" {
		h.log.Infof("created %s container in new machine for holding %s", machine, msg)
	} else {
		h.log.Infof("created %s container in machine %s for holding %s", machine, machineParams.ParentId, msg)
	}
	h.results[id] = machine
	return nil
}

func (c *addCommand) Run(ctx *cmd.Context) error {
	client, err := c.getClientAPI()
	if err != nil {
		return errors.Trace(err)
	}
	defer client.Close()

	var machineManager MachineManagerAPI
	if len(c.Disks) > 0 {
		machineManager, err = c.getMachineManagerAPI()
		if err != nil {
			return errors.Trace(err)
		}
		defer machineManager.Close()
		if machineManager.BestAPIVersion() < 1 {
			return errors.New("cannot add machines with disks: not supported by the API server")
		}
	}

	logger.Infof("load config")
	var config *config.Config
	if defaultStore, err := configstore.Default(); err != nil {
		return err
	} else if config, err = c.Config(defaultStore, client); err != nil {
		return err
	}

	if c.Placement != nil && c.Placement.Scope == "ssh" {
		logger.Infof("manual provisioning")
		args := manual.ProvisionMachineArgs{
			Host:   c.Placement.Directive,
			Client: client,
			Stdin:  ctx.Stdin,
			Stdout: ctx.Stdout,
			Stderr: ctx.Stderr,
			UpdateBehavior: &params.UpdateBehavior{
				config.EnableOSRefreshUpdate(),
				config.EnableOSUpgrade(),
			},
		}
		machineId, err := manualProvisioner(args)
		if err == nil {
			ctx.Infof("created machine %v", machineId)
		}
		return err
	}

	logger.Infof("environment provisioning")
	if c.Placement != nil && c.Placement.Scope == "env-uuid" {
		c.Placement.Scope = client.EnvironmentUUID()
	}

	if c.Placement != nil && c.Placement.Scope == instance.MachineScope {
		// It does not make sense to add-machine <id>.
		return fmt.Errorf("machine-id cannot be specified when adding machines")
	}

	jobs := []multiwatcher.MachineJob{multiwatcher.JobHostUnits}

	envVersion, err := envcmd.GetEnvironmentVersion(client)
	if err != nil {
		return err
	}

	// Servers before 1.21-alpha2 don't have the networker so don't
	// try to use JobManageNetworking with them.
	//
	// In case of MAAS and Joyent JobManageNetworking is not added
	// to ensure the non-intrusive start of a networker like above
	// for the manual provisioning. See this related joyent bug
	// http://pad.lv/1401423
	if envVersion.Compare(version.MustParse("1.21-alpha2")) >= 0 &&
		config.Type() != provider.MAAS &&
		config.Type() != provider.Joyent {
		jobs = append(jobs, multiwatcher.JobManageNetworking)
	}

	machineParams := params.AddMachineParams{
		Placement:   c.Placement,
		Series:      c.Series,
		Constraints: c.Constraints,
		Jobs:        jobs,
		Disks:       c.Disks,
	}
	machines := make([]params.AddMachineParams, c.NumMachines)
	for i := 0; i < c.NumMachines; i++ {
		machines[i] = machineParams
	}

	var results []params.AddMachinesResult
	// If storage is specified, we attempt to use a new API on the service facade.
	if len(c.Disks) > 0 {
		results, err = machineManager.AddMachines(machines)
	} else {
		results, err = client.AddMachines(machines)
		if params.IsCodeNotImplemented(err) {
			if c.Placement != nil {
				containerType, parseErr := instance.ParseContainerType(c.Placement.Scope)
				if parseErr != nil {
					// The user specified a non-container placement directive:
//.........这里部分代码省略.........

// AddUnits starts n units of the given service and allocates machines
// to them as necessary.
func AddUnits(st *state.State, svc *state.Service, n int, machineIdSpec string) ([]*state.Unit, error) {
	units := make([]*state.Unit, n)
	// Hard code for now till we implement a different approach.
	policy := state.AssignCleanEmpty
	// All units should have the same networks as the service.
	networks, err := svc.Networks()
	if err != nil {
		return nil, fmt.Errorf("cannot get service %q networks: %v", svc.Name(), err)
	}
	// TODO what do we do if we fail half-way through this process?
	for i := 0; i < n; i++ {
		unit, err := svc.AddUnit()
		if err != nil {
			return nil, fmt.Errorf("cannot add unit %d/%d to service %q: %v", i+1, n, svc.Name(), err)
		}
		if machineIdSpec != "" {
			if n != 1 {
				return nil, fmt.Errorf("cannot add multiple units of service %q to a single machine", svc.Name())
			}
			// machineIdSpec may be an existing machine or container, eg 3/lxc/2
			// or a new container on a machine, eg lxc:3
			mid := machineIdSpec
			var containerType instance.ContainerType
			specParts := strings.SplitN(machineIdSpec, ":", 2)
			if len(specParts) > 1 {
				firstPart := specParts[0]
				var err error
				if containerType, err = instance.ParseContainerType(firstPart); err == nil {
					mid = specParts[1]
				} else {
					mid = machineIdSpec
				}
			}
			if !names.IsMachine(mid) {
				return nil, fmt.Errorf("invalid force machine id %q", mid)
			}
			var unitCons *constraints.Value
			unitCons, err = unit.Constraints()
			if err != nil {
				return nil, err
			}

			var err error
			var m *state.Machine
			// If a container is to be used, create it.
			if containerType != "" {
				// Create the new machine marked as dirty so that
				// nothing else will grab it before we assign the unit to it.
				template := state.MachineTemplate{
					Series:            unit.Series(),
					Jobs:              []state.MachineJob{state.JobHostUnits},
					Dirty:             true,
					Constraints:       *unitCons,
					RequestedNetworks: networks,
				}
				m, err = st.AddMachineInsideMachine(template, mid, containerType)
			} else {
				m, err = st.Machine(mid)
			}
			if err != nil {
				return nil, fmt.Errorf("cannot assign unit %q to machine: %v", unit.Name(), err)
			}
			err = unit.AssignToMachine(m)

			if err != nil {
				return nil, err
			}
		} else if err := st.AssignUnit(unit, policy); err != nil {
			return nil, err
		}
		units[i] = unit
	}
	return units, nil
}

// addMachine creates a new top-level machine or container in the environment.
func (h *bundleHandler) addMachine(id string, p bundlechanges.AddMachineParams) error {
	services := h.servicesForMachineChange(id)
	// Note that we always have at least one application that justifies the
	// creation of this machine.
	msg := services[0] + " unit"
	svcLen := len(services)
	if svcLen != 1 {
		msg = strings.Join(services[:svcLen-1], ", ") + " and " + services[svcLen-1] + " units"
	}
	// Check whether the desired number of units already exist in the
	// environment, in which case avoid adding other machines to host those
	// application units.
	machine := h.chooseMachine(services...)
	if machine != "" {
		h.results[id] = machine
		notify := make([]string, 0, svcLen)
		for _, application := range services {
			if !h.ignoredMachines[application] {
				h.ignoredMachines[application] = true
				notify = append(notify, application)
			}
		}
		svcLen = len(notify)
		switch svcLen {
		case 0:
			return nil
		case 1:
			msg = notify[0]
		default:
			msg = strings.Join(notify[:svcLen-1], ", ") + " and " + notify[svcLen-1]
		}
		h.log.Infof("avoid creating other machines to host %s units", msg)
		return nil
	}
	cons, err := constraints.Parse(p.Constraints)
	if err != nil {
		// This should never happen, as the bundle is already verified.
		return errors.Annotate(err, "invalid constraints for machine")
	}
	machineParams := params.AddMachineParams{
		Constraints: cons,
		Series:      p.Series,
		Jobs:        []multiwatcher.MachineJob{multiwatcher.JobHostUnits},
	}
	if ct := p.ContainerType; ct != "" {
		// for backwards compatibility with 1.x bundles, we treat lxc
		// placement directives as lxd.
		if ct == "lxc" {
			if !h.warnedLXC {
				h.log.Infof("Bundle has one or more containers specified as lxc. lxc containers are deprecated in Juju 2.0. lxd containers will be deployed instead.")
				h.warnedLXC = true
			}
			ct = string(instance.LXD)
		}
		containerType, err := instance.ParseContainerType(ct)
		if err != nil {
			return errors.Annotatef(err, "cannot create machine for holding %s", msg)
		}
		machineParams.ContainerType = containerType
		if p.ParentId != "" {
			machineParams.ParentId, err = h.resolveMachine(p.ParentId)
			if err != nil {
				return errors.Annotatef(err, "cannot retrieve parent placement for %s", msg)
			}
		}
	}
	r, err := h.api.AddMachines([]params.AddMachineParams{machineParams})
	if err != nil {
		return errors.Annotatef(err, "cannot create machine for holding %s", msg)
	}
	if r[0].Error != nil {
		return errors.Annotatef(r[0].Error, "cannot create machine for holding %s", msg)
	}
	machine = r[0].Machine
	if p.ContainerType == "" {
		logger.Debugf("created new machine %s for holding %s", machine, msg)
	} else if p.ParentId == "" {
		logger.Debugf("created %s container in new machine for holding %s", machine, msg)
	} else {
		logger.Debugf("created %s container in machine %s for holding %s", machine, machineParams.ParentId, msg)
	}
	h.results[id] = machine
	return nil
}

func (mm *MachineManagerAPI) addOneMachine(p params.AddMachineParams) (*state.Machine, error) {
	if p.ParentId != "" && p.ContainerType == "" {
		return nil, fmt.Errorf("parent machine specified without container type")
	}
	if p.ContainerType != "" && p.Placement != nil {
		return nil, fmt.Errorf("container type and placement are mutually exclusive")
	}
	if p.Placement != nil {
		// Extract container type and parent from container placement directives.
		containerType, err := instance.ParseContainerType(p.Placement.Scope)
		if err == nil {
			p.ContainerType = containerType
			p.ParentId = p.Placement.Directive
			p.Placement = nil
		}
	}

	if p.ContainerType != "" || p.Placement != nil {
		// Guard against dubious client by making sure that
		// the following attributes can only be set when we're
		// not using placement.
		p.InstanceId = ""
		p.Nonce = ""
		p.HardwareCharacteristics = instance.HardwareCharacteristics{}
		p.Addrs = nil
	}

	if p.Series == "" {
		conf, err := mm.st.ModelConfig()
		if err != nil {
			return nil, err
		}
		p.Series = config.PreferredSeries(conf)
	}

	var placementDirective string
	if p.Placement != nil {
		env, err := mm.st.Model()
		if err != nil {
			return nil, err
		}
		// For 1.21 we should support both UUID and name, and with 1.22
		// just support UUID
		if p.Placement.Scope != env.Name() && p.Placement.Scope != env.UUID() {
			return nil, fmt.Errorf("invalid model name %q", p.Placement.Scope)
		}
		placementDirective = p.Placement.Directive
	}

	volumes := make([]state.MachineVolumeParams, 0, len(p.Disks))
	for _, cons := range p.Disks {
		if cons.Count == 0 {
			return nil, errors.Errorf("invalid volume params: count not specified")
		}
		// Pool and Size are validated by AddMachineX.
		volumeParams := state.VolumeParams{
			Pool: cons.Pool,
			Size: cons.Size,
		}
		volumeAttachmentParams := state.VolumeAttachmentParams{}
		for i := uint64(0); i < cons.Count; i++ {
			volumes = append(volumes, state.MachineVolumeParams{
				volumeParams, volumeAttachmentParams,
			})
		}
	}

	jobs, err := common.StateJobs(p.Jobs)
	if err != nil {
		return nil, err
	}
	template := state.MachineTemplate{
		Series:      p.Series,
		Constraints: p.Constraints,
		Volumes:     volumes,
		InstanceId:  p.InstanceId,
		Jobs:        jobs,
		Nonce:       p.Nonce,
		HardwareCharacteristics: p.HardwareCharacteristics,
		Addresses:               params.NetworkAddresses(p.Addrs),
		Placement:               placementDirective,
	}
	if p.ContainerType == "" {
		return mm.st.AddOneMachine(template)
	}
	if p.ParentId != "" {
		return mm.st.AddMachineInsideMachine(template, p.ParentId, p.ContainerType)
	}
	return mm.st.AddMachineInsideNewMachine(template, template, p.ContainerType)
}

func (c *AddMachineCommand) Run(ctx *cmd.Context) error {
	if c.Placement != nil && c.Placement.Scope == "ssh" {
		args := manual.ProvisionMachineArgs{
			Host:    c.Placement.Directive,
			EnvName: c.EnvName,
			Stdin:   ctx.Stdin,
			Stdout:  ctx.Stdout,
			Stderr:  ctx.Stderr,
		}
		_, err := manual.ProvisionMachine(args)
		return err
	}

	client, err := juju.NewAPIClientFromName(c.EnvName)
	if err != nil {
		return err
	}
	defer client.Close()

	if c.Placement != nil && c.Placement.Scope == instance.MachineScope {
		// It does not make sense to add-machine <id>.
		return fmt.Errorf("machine-id cannot be specified when adding machines")
	}

	machineParams := params.AddMachineParams{
		Placement:   c.Placement,
		Series:      c.Series,
		Constraints: c.Constraints,
		Jobs:        []params.MachineJob{params.JobHostUnits},
	}
	results, err := client.AddMachines([]params.AddMachineParams{machineParams})
	if params.IsCodeNotImplemented(err) {
		if c.Placement != nil {
			containerType, parseErr := instance.ParseContainerType(c.Placement.Scope)
			if parseErr != nil {
				// The user specified a non-container placement directive:
				// return original API not implemented error.
				return err
			}
			machineParams.ContainerType = containerType
			machineParams.ParentId = c.Placement.Directive
			machineParams.Placement = nil
		}
		logger.Infof(
			"AddMachinesWithPlacement not supported by the API server, " +
				"falling back to 1.18 compatibility mode",
		)
		results, err = client.AddMachines1dot18([]params.AddMachineParams{machineParams})
	}
	if err != nil {
		return err
	}

	// Currently, only one machine is added, but in future there may be several added in one call.
	machineInfo := results[0]
	if machineInfo.Error != nil {
		return machineInfo.Error
	}
	machineId := machineInfo.Machine

	if names.IsContainerMachine(machineId) {
		ctx.Infof("created container %v", machineId)
	} else {
		ctx.Infof("created machine %v", machineId)
	}
	return nil
}