func (e *exporter) newMachine(exParent description.Machine, machine *Machine, instances map[string]instanceData, portsData []portsDoc) (description.Machine, error) {
	args := description.MachineArgs{
		Id:            machine.MachineTag(),
		Nonce:         machine.doc.Nonce,
		PasswordHash:  machine.doc.PasswordHash,
		Placement:     machine.doc.Placement,
		Series:        machine.doc.Series,
		ContainerType: machine.doc.ContainerType,
	}

	if supported, ok := machine.SupportedContainers(); ok {
		containers := make([]string, len(supported))
		for i, containerType := range supported {
			containers[i] = string(containerType)
		}
		args.SupportedContainers = &containers
	}

	for _, job := range machine.Jobs() {
		args.Jobs = append(args.Jobs, job.MigrationValue())
	}

	// A null value means that we don't yet know which containers
	// are supported. An empty slice means 'no containers are supported'.
	var exMachine description.Machine
	if exParent == nil {
		exMachine = e.model.AddMachine(args)
	} else {
		exMachine = exParent.AddContainer(args)
	}
	exMachine.SetAddresses(
		e.newAddressArgsSlice(machine.doc.MachineAddresses),
		e.newAddressArgsSlice(machine.doc.Addresses))
	exMachine.SetPreferredAddresses(
		e.newAddressArgs(machine.doc.PreferredPublicAddress),
		e.newAddressArgs(machine.doc.PreferredPrivateAddress))

	// We fully expect the machine to have tools set, and that there is
	// some instance data.
	instData, found := instances[machine.doc.Id]
	if !found {
		return nil, errors.NotValidf("missing instance data for machine %s", machine.Id())
	}
	exMachine.SetInstance(e.newCloudInstanceArgs(instData))

	// Find the current machine status.
	globalKey := machine.globalKey()
	statusArgs, err := e.statusArgs(globalKey)
	if err != nil {
		return nil, errors.Annotatef(err, "status for machine %s", machine.Id())
	}
	exMachine.SetStatus(statusArgs)
	exMachine.SetStatusHistory(e.statusHistoryArgs(globalKey))

	tools, err := machine.AgentTools()
	if err != nil {
		// This means the tools aren't set, but they should be.
		return nil, errors.Trace(err)
	}

	exMachine.SetTools(description.AgentToolsArgs{
		Version: tools.Version,
		URL:     tools.URL,
		SHA256:  tools.SHA256,
		Size:    tools.Size,
	})

	for _, args := range e.networkPortsArgsForMachine(machine.Id(), portsData) {
		exMachine.AddNetworkPorts(args)
	}

	exMachine.SetAnnotations(e.getAnnotations(globalKey))

	constraintsArgs, err := e.constraintsArgs(globalKey)
	if err != nil {
		return nil, errors.Trace(err)
	}
	exMachine.SetConstraints(constraintsArgs)

	return exMachine, nil
}