func (c *restoreCommand) Run(ctx *cmd.Context) error {
	if c.showDescription {
		fmt.Fprintf(ctx.Stdout, "%s\n", c.Info().Purpose)
		return nil
	}
	if err := c.Log.Start(ctx); err != nil {
		return err
	}
	agentConf, err := extractConfig(c.backupFile)
	if err != nil {
		return errors.Annotate(err, "cannot extract configuration from backup file")
	}
	progress("extracted credentials from backup file")
	store, err := configstore.Default()
	if err != nil {
		return err
	}
	cfg, err := c.Config(store)
	if err != nil {
		return err
	}
	env, err := rebootstrap(cfg, ctx, c.Constraints)
	if err != nil {
		return errors.Annotate(err, "cannot re-bootstrap environment")
	}
	progress("connecting to newly bootstrapped instance")
	var apiState *api.State
	// The state server backend may not be ready to accept logins so we retry.
	// We'll do up to 8 retries over 2 minutes to give the server time to come up.
	// Typically we expect only 1 retry will be needed.
	attempt := utils.AttemptStrategy{Delay: 15 * time.Second, Min: 8}
	for a := attempt.Start(); a.Next(); {
		apiState, err = juju.NewAPIState(env, api.DefaultDialOpts())
		if err == nil || errors.Cause(err).Error() != "EOF" {
			break
		}
		progress("bootstrapped instance not ready - attempting to redial")
	}
	if err != nil {
		return errors.Annotate(err, "cannot connect to bootstrap instance")
	}
	progress("restoring bootstrap machine")
	machine0Addr, err := restoreBootstrapMachine(apiState, c.backupFile, agentConf)
	if err != nil {
		return errors.Annotate(err, "cannot restore bootstrap machine")
	}
	progress("restored bootstrap machine")

	apiState, err = juju.NewAPIState(env, api.DefaultDialOpts())
	progress("opening state")
	if err != nil {
		return errors.Annotate(err, "cannot connect to api server")
	}
	progress("updating all machines")
	if err := updateAllMachines(apiState, machine0Addr); err != nil {
		return errors.Annotate(err, "cannot update machines")
	}
	return nil
}

func (cs *NewAPIStateSuite) TestNewAPIState(c *gc.C) {
	cfg, err := config.New(config.NoDefaults, dummy.SampleConfig())
	c.Assert(err, jc.ErrorIsNil)
	ctx := envtesting.BootstrapContext(c)
	env, err := environs.Prepare(cfg, ctx, configstore.NewMem())
	c.Assert(err, jc.ErrorIsNil)

	storageDir := c.MkDir()
	cs.PatchValue(&envtools.DefaultBaseURL, storageDir)
	stor, err := filestorage.NewFileStorageWriter(storageDir)
	c.Assert(err, jc.ErrorIsNil)
	envtesting.UploadFakeTools(c, stor, "released", "released")

	err = bootstrap.Bootstrap(ctx, env, bootstrap.BootstrapParams{})
	c.Assert(err, jc.ErrorIsNil)

	cfg = env.Config()
	cfg, err = cfg.Apply(map[string]interface{}{
		"secret": "fnord",
	})
	c.Assert(err, jc.ErrorIsNil)
	err = env.SetConfig(cfg)
	c.Assert(err, jc.ErrorIsNil)

	st, err := juju.NewAPIState(dummy.AdminUserTag(), env, api.DialOpts{})
	c.Assert(st, gc.NotNil)

	// the secrets will not be updated, as they already exist
	attrs, err := st.Client().EnvironmentGet()
	c.Assert(attrs["secret"], gc.Equals, "pork")

	c.Assert(st.Close(), gc.IsNil)
}

func (s *cmdControllerSuite) TestSystemKillCallsEnvironDestroyOnHostedEnviron(c *gc.C) {
	st := s.Factory.MakeEnvironment(c, &factory.EnvParams{
		Name: "foo",
	})
	defer st.Close()

	st.SwitchBlockOn(state.DestroyBlock, "TestBlockDestroyEnvironment")
	st.Close()

	opc := make(chan dummy.Operation, 200)
	dummy.Listen(opc)

	conn, err := juju.NewAPIState(s.AdminUserTag(c), s.Environ, api.DialOpts{})
	c.Assert(err, jc.ErrorIsNil)
	s.AddCleanup(func(*gc.C) { conn.Close() })
	client := undertakerapi.NewClient(conn)

	startTime := time.Date(2015, time.September, 1, 17, 2, 1, 0, time.UTC)
	mClock := testing.NewClock(startTime)
	undertaker.NewUndertaker(client, mClock)

	store, err := configstore.Default()
	_, err = store.ReadInfo("dummyenv")
	c.Assert(err, jc.ErrorIsNil)

	s.run(c, "kill-controller", "dummyenv", "-y")

	// Ensure that Destroy was called on the hosted environment ...
	opRecvTimeout(c, st, opc, dummy.OpDestroy{})

	// ... and that the configstore was removed.
	_, err = store.ReadInfo("dummyenv")
	c.Assert(err, jc.Satisfies, errors.IsNotFound)
}

func (*NewAPIStateSuite) TestNewAPIState(c *gc.C) {
	cfg, err := config.New(config.NoDefaults, dummy.SampleConfig())
	c.Assert(err, gc.IsNil)
	ctx := coretesting.Context(c)
	env, err := environs.Prepare(cfg, ctx, configstore.NewMem())
	c.Assert(err, gc.IsNil)

	envtesting.UploadFakeTools(c, env.Storage())
	err = bootstrap.Bootstrap(ctx, env, environs.BootstrapParams{})
	c.Assert(err, gc.IsNil)

	cfg = env.Config()
	cfg, err = cfg.Apply(map[string]interface{}{
		"secret": "fnord",
	})
	c.Assert(err, gc.IsNil)
	err = env.SetConfig(cfg)
	c.Assert(err, gc.IsNil)

	st, err := juju.NewAPIState(env, api.DialOpts{})
	c.Assert(st, gc.NotNil)

	// the secrets will not be updated, as they already exist
	attrs, err := st.Client().EnvironmentGet()
	c.Assert(attrs["secret"], gc.Equals, "pork")

	c.Assert(st.Close(), gc.IsNil)
}

func (s *JujuConnSuite) setUpConn(c *gc.C) {
	if s.RootDir != "" {
		panic("JujuConnSuite.setUpConn without teardown")
	}
	s.RootDir = c.MkDir()
	s.oldHome = utils.Home()
	home := filepath.Join(s.RootDir, "/home/ubuntu")
	err := os.MkdirAll(home, 0777)
	c.Assert(err, gc.IsNil)
	utils.SetHome(home)
	s.oldJujuHome = osenv.SetJujuHome(filepath.Join(home, ".juju"))
	err = os.Mkdir(osenv.JujuHome(), 0777)
	c.Assert(err, gc.IsNil)

	err = os.MkdirAll(s.DataDir(), 0777)
	c.Assert(err, gc.IsNil)
	s.PatchEnvironment(osenv.JujuEnvEnvKey, "")

	// TODO(rog) remove these files and add them only when
	// the tests specifically need them (in cmd/juju for example)
	s.writeSampleConfig(c, osenv.JujuHomePath("environments.yaml"))

	err = ioutil.WriteFile(osenv.JujuHomePath("dummyenv-cert.pem"), []byte(testing.CACert), 0666)
	c.Assert(err, gc.IsNil)

	err = ioutil.WriteFile(osenv.JujuHomePath("dummyenv-private-key.pem"), []byte(testing.CAKey), 0600)
	c.Assert(err, gc.IsNil)

	store, err := configstore.Default()
	c.Assert(err, gc.IsNil)
	s.ConfigStore = store

	ctx := testing.Context(c)
	environ, err := environs.PrepareFromName("dummyenv", ctx, s.ConfigStore)
	c.Assert(err, gc.IsNil)
	// sanity check we've got the correct environment.
	c.Assert(environ.Config().Name(), gc.Equals, "dummyenv")
	s.PatchValue(&dummy.DataDir, s.DataDir())
	s.LogDir = c.MkDir()
	s.PatchValue(&dummy.LogDir, s.LogDir)

	versions := PreferredDefaultVersions(environ.Config(), version.Binary{Number: version.Current.Number, Series: "precise", Arch: "amd64"})
	versions = append(versions, version.Current)

	// Upload tools for both preferred and fake default series
	envtesting.MustUploadFakeToolsVersions(environ.Storage(), versions...)
	err = bootstrap.Bootstrap(ctx, environ, bootstrap.BootstrapParams{})
	c.Assert(err, gc.IsNil)

	s.BackingState = environ.(GetStater).GetStateInAPIServer()

	s.State, err = newState(environ, s.BackingState.MongoConnectionInfo())
	c.Assert(err, gc.IsNil)

	s.APIState, err = juju.NewAPIState(environ, api.DialOpts{})
	c.Assert(err, gc.IsNil)

	s.Environ = environ
}

func (s *cmdControllerSuite) createEnv(c *gc.C, envname string, isServer bool) {
	conn, err := juju.NewAPIState(s.AdminUserTag(c), s.Environ, api.DialOpts{})
	c.Assert(err, jc.ErrorIsNil)
	s.AddCleanup(func(*gc.C) { conn.Close() })
	envManager := environmentmanager.NewClient(conn)
	_, err = envManager.CreateEnvironment(s.AdminUserTag(c).Id(), nil, map[string]interface{}{
		"name":            envname,
		"authorized-keys": "ssh-key",
		"state-server":    isServer,
	})
	c.Assert(err, jc.ErrorIsNil)
}

func (t *LiveTests) TestCheckEnvironmentOnConnect(c *gc.C) {
	// When new connection is established to a bootstraped environment,
	// it is checked that we are running against a juju-core environment.
	if !t.CanOpenState {
		c.Skip("CanOpenState is false; cannot open state connection")
	}
	t.BootstrapOnce(c)

	apiState, err := juju.NewAPIState(t.Env, api.DefaultDialOpts())
	c.Assert(err, gc.IsNil)
	apiState.Close()
}

func (s *blockSuite) SetUpTest(c *gc.C) {
	s.JujuConnSuite.SetUpTest(c)

	conn, err := juju.NewAPIState(s.AdminUserTag(c), s.Environ, api.DialOpts{})
	c.Assert(err, jc.ErrorIsNil)
	s.AddCleanup(func(*gc.C) { conn.Close() })

	s.ctx = &mockContext{
		agentConfig: &mockAgentConfig{dataDir: s.DataDir()},
		apiState:    conn,
		state:       s.State,
	}
	s.blockClient = block.NewClient(conn)
}

func (s *modelmanagerSuite) OpenAPI(c *gc.C) *modelmanager.Client {
	conn, err := juju.NewAPIState(s.AdminUserTag(c), s.Environ, api.DialOpts{})
	c.Assert(err, jc.ErrorIsNil)
	s.AddCleanup(func(*gc.C) { conn.Close() })
	return modelmanager.NewClient(conn)
}

func (c *restoreCommand) Run(ctx *cmd.Context) error {
	if c.showDescription {
		fmt.Fprintf(ctx.Stdout, "%s\n", c.Info().Purpose)
		return nil
	}
	if err := c.Log.Start(ctx); err != nil {
		return err
	}
	agentConf, err := extractConfig(c.backupFile)
	if err != nil {
		return errors.Annotate(err, "cannot extract configuration from backup file")
	}
	progress("extracted credentials from backup file")
	store, err := configstore.Default()
	if err != nil {
		return err
	}
	cfg, err := c.Config(store, nil)
	if err != nil {
		return err
	}
	env, err := rebootstrap(cfg, ctx, c.Constraints)
	if err != nil {
		return errors.Annotate(err, "cannot re-bootstrap environment")
	}
	progress("connecting to newly bootstrapped instance")
	var apiState api.Connection
	// The state server backend may not be ready to accept logins so we retry.
	// We'll do up to 8 retries over 2 minutes to give the server time to come up.
	// Typically we expect only 1 retry will be needed.
	attempt := utils.AttemptStrategy{Delay: 15 * time.Second, Min: 8}
	// While specifying the admin user will work for now, as soon as we allow
	// the users to have a different initial user name, or they have changed
	// the password for the admin user, this will fail.
	owner := names.NewUserTag("admin")
	for a := attempt.Start(); a.Next(); {
		apiState, err = juju.NewAPIState(owner, env, api.DefaultDialOpts())
		if err == nil || errors.Cause(err).Error() != "EOF" {
			break
		}
		progress("bootstrapped instance not ready - attempting to redial")
	}
	if err != nil {
		return errors.Annotate(err, "cannot connect to bootstrap instance")
	}
	progress("restoring bootstrap machine")
	machine0Addr, err := restoreBootstrapMachine(apiState, c.backupFile, agentConf)
	if err != nil {
		return errors.Annotate(err, "cannot restore bootstrap machine")
	}
	progress("restored bootstrap machine")

	apiState, err = juju.NewAPIState(owner, env, api.DefaultDialOpts())
	progress("opening state")
	if err != nil {
		return errors.Annotate(err, "cannot connect to api server")
	}
	progress("updating all machines")
	results, err := updateAllMachines(apiState, machine0Addr)
	if err != nil {
		return errors.Annotate(err, "cannot update machines")
	}
	var message string
	for _, result := range results {
		if result.err != nil {
			message = fmt.Sprintf("Update of machine %q failed: %v", result.machineName, result.err)
		} else {
			message = fmt.Sprintf("Succesful update of machine %q", result.machineName)
		}
		progress(message)
	}
	return nil
}

func (s *JujuConnSuite) setUpConn(c *gc.C) {
	if s.RootDir != "" {
		panic("JujuConnSuite.setUpConn without teardown")
	}
	s.RootDir = c.MkDir()
	s.oldHome = utils.Home()
	home := filepath.Join(s.RootDir, "/home/ubuntu")
	err := os.MkdirAll(home, 0777)
	c.Assert(err, jc.ErrorIsNil)
	utils.SetHome(home)
	s.oldJujuHome = osenv.SetJujuHome(filepath.Join(home, ".juju"))
	err = os.Mkdir(osenv.JujuHome(), 0777)
	c.Assert(err, jc.ErrorIsNil)

	err = os.MkdirAll(s.DataDir(), 0777)
	c.Assert(err, jc.ErrorIsNil)
	s.PatchEnvironment(osenv.JujuEnvEnvKey, "")

	// TODO(rog) remove these files and add them only when
	// the tests specifically need them (in cmd/juju for example)
	s.writeSampleConfig(c, osenv.JujuHomePath("environments.yaml"))

	err = ioutil.WriteFile(osenv.JujuHomePath("dummyenv-cert.pem"), []byte(testing.CACert), 0666)
	c.Assert(err, jc.ErrorIsNil)

	err = ioutil.WriteFile(osenv.JujuHomePath("dummyenv-private-key.pem"), []byte(testing.CAKey), 0600)
	c.Assert(err, jc.ErrorIsNil)

	store, err := configstore.Default()
	c.Assert(err, jc.ErrorIsNil)
	s.ConfigStore = store

	ctx := testing.Context(c)
	environ, err := environs.PrepareFromName("dummyenv", envcmd.BootstrapContext(ctx), s.ConfigStore)
	c.Assert(err, jc.ErrorIsNil)
	// sanity check we've got the correct environment.
	c.Assert(environ.Config().Name(), gc.Equals, "dummyenv")
	s.PatchValue(&dummy.DataDir, s.DataDir())
	s.LogDir = c.MkDir()
	s.PatchValue(&dummy.LogDir, s.LogDir)

	versions := PreferredDefaultVersions(environ.Config(), version.Binary{Number: version.Current.Number, Series: "precise", Arch: "amd64"})
	versions = append(versions, version.Current)

	// Upload tools for both preferred and fake default series
	s.DefaultToolsStorageDir = c.MkDir()
	s.PatchValue(&tools.DefaultBaseURL, s.DefaultToolsStorageDir)
	stor, err := filestorage.NewFileStorageWriter(s.DefaultToolsStorageDir)
	c.Assert(err, jc.ErrorIsNil)
	// Upload tools to both release and devel streams since config will dictate that we
	// end up looking in both places.
	envtesting.AssertUploadFakeToolsVersions(c, stor, "released", "released", versions...)
	envtesting.AssertUploadFakeToolsVersions(c, stor, "devel", "devel", versions...)
	s.DefaultToolsStorage = stor

	err = bootstrap.Bootstrap(envcmd.BootstrapContext(ctx), environ, bootstrap.BootstrapParams{})
	c.Assert(err, jc.ErrorIsNil)

	s.BackingState = environ.(GetStater).GetStateInAPIServer()

	s.State, err = newState(environ, s.BackingState.MongoConnectionInfo())
	c.Assert(err, jc.ErrorIsNil)

	s.APIState, err = juju.NewAPIState(s.AdminUserTag(c), environ, api.DialOpts{})
	c.Assert(err, jc.ErrorIsNil)

	err = s.State.SetAPIHostPorts(s.APIState.APIHostPorts())
	c.Assert(err, jc.ErrorIsNil)

	// Make sure the config store has the api endpoint address set
	info, err := s.ConfigStore.ReadInfo("dummyenv")
	c.Assert(err, jc.ErrorIsNil)
	endpoint := info.APIEndpoint()
	endpoint.Addresses = []string{s.APIState.APIHostPorts()[0][0].String()}
	info.SetAPIEndpoint(endpoint)
	err = info.Write()
	c.Assert(err, jc.ErrorIsNil)

	// Make sure the jenv file has the local host ports.
	c.Logf("jenv host ports: %#v", s.APIState.APIHostPorts())

	s.Environ = environ

	// Insert expected values...
	servingInfo := state.StateServingInfo{
		PrivateKey:   testing.ServerKey,
		Cert:         testing.ServerCert,
		CAPrivateKey: testing.CAKey,
		SharedSecret: "really, really secret",
		APIPort:      4321,
		StatePort:    1234,
	}
	s.State.SetStateServingInfo(servingInfo)
}

func (t *LiveTests) TestBootstrapAndDeploy(c *gc.C) {
	if !t.CanOpenState || !t.HasProvisioner {
		c.Skip(fmt.Sprintf("skipping provisioner test, CanOpenState: %v, HasProvisioner: %v", t.CanOpenState, t.HasProvisioner))
	}
	t.BootstrapOnce(c)

	// TODO(niemeyer): Stop growing this kitchen sink test and split it into proper parts.

	c.Logf("opening state")
	st := t.Env.(testing.GetStater).GetStateInAPIServer()

	c.Logf("opening API connection")
	apiState, err := juju.NewAPIState(t.Env, api.DefaultDialOpts())
	c.Assert(err, gc.IsNil)
	defer apiState.Close()

	// Check that the agent version has made it through the
	// bootstrap process (it's optional in the config.Config)
	cfg, err := st.EnvironConfig()
	c.Assert(err, gc.IsNil)
	agentVersion, ok := cfg.AgentVersion()
	c.Check(ok, gc.Equals, true)
	c.Check(agentVersion, gc.Equals, version.Current.Number)

	// Check that the constraints have been set in the environment.
	cons, err := st.EnvironConstraints()
	c.Assert(err, gc.IsNil)
	c.Assert(cons.String(), gc.Equals, "mem=2048M")

	// Wait for machine agent to come up on the bootstrap
	// machine and find the deployed series from that.
	m0, err := st.Machine("0")
	c.Assert(err, gc.IsNil)

	instId0, err := m0.InstanceId()
	c.Assert(err, gc.IsNil)

	// Check that the API connection is working.
	status, err := apiState.Client().Status(nil)
	c.Assert(err, gc.IsNil)
	c.Assert(status.Machines["0"].InstanceId, gc.Equals, string(instId0))

	mw0 := newMachineToolWaiter(m0)
	defer mw0.Stop()

	// If the series has not been specified, we expect the most recent Ubuntu LTS release to be used.
	expectedVersion := version.Current
	expectedVersion.Series = config.LatestLtsSeries()

	mtools0 := waitAgentTools(c, mw0, expectedVersion)

	// Create a new service and deploy a unit of it.
	c.Logf("deploying service")
	repoDir := c.MkDir()
	url := charmtesting.Charms.ClonedURL(repoDir, mtools0.Version.Series, "dummy")
	sch, err := testing.PutCharm(st, url, &charm.LocalRepository{Path: repoDir}, false)
	c.Assert(err, gc.IsNil)
	svc, err := st.AddService("dummy", "user-admin", sch, nil)
	c.Assert(err, gc.IsNil)
	units, err := juju.AddUnits(st, svc, 1, "")
	c.Assert(err, gc.IsNil)
	unit := units[0]

	// Wait for the unit's machine and associated agent to come up
	// and announce itself.
	mid1, err := unit.AssignedMachineId()
	c.Assert(err, gc.IsNil)
	m1, err := st.Machine(mid1)
	c.Assert(err, gc.IsNil)
	mw1 := newMachineToolWaiter(m1)
	defer mw1.Stop()
	waitAgentTools(c, mw1, mtools0.Version)

	err = m1.Refresh()
	c.Assert(err, gc.IsNil)
	instId1, err := m1.InstanceId()
	c.Assert(err, gc.IsNil)
	uw := newUnitToolWaiter(unit)
	defer uw.Stop()
	utools := waitAgentTools(c, uw, expectedVersion)

	// Check that we can upgrade the environment.
	newVersion := utools.Version
	newVersion.Patch++
	t.checkUpgrade(c, st, newVersion, mw0, mw1, uw)

	// BUG(niemeyer): Logic below is very much wrong. Must be:
	//
	// 1. EnsureDying on the unit and EnsureDying on the machine
	// 2. Unit dies by itself
	// 3. Machine removes dead unit
	// 4. Machine dies by itself
	// 5. Provisioner removes dead machine
	//

	// Now remove the unit and its assigned machine and
	// check that the PA removes it.
	c.Logf("removing unit")
	err = unit.Destroy()
	c.Assert(err, gc.IsNil)
//.........这里部分代码省略.........

func (c *restoreCommand) Run(ctx *cmd.Context) error {
	if c.showDescription {
		fmt.Fprintf(ctx.Stdout, "%s\n", c.Info().Purpose)
		return nil
	}
	if err := c.Log.Start(ctx); err != nil {
		return err
	}
	agentConf, err := extractConfig(c.backupFile)
	if err != nil {
		return fmt.Errorf("cannot extract configuration from backup file: %v", err)
	}
	progress("extracted credentials from backup file")
	store, err := configstore.Default()
	if err != nil {
		return err
	}
	cfg, err := c.Config(store)
	if err != nil {
		return err
	}
	env, err := rebootstrap(cfg, ctx, c.Constraints)
	if err != nil {
		return fmt.Errorf("cannot re-bootstrap environment: %v", err)
	}
	progress("connecting to newly bootstrapped instance")
	var apiState *api.State
	// The state server backend may not be ready to accept logins so we retry.
	// We'll do up to 8 retries over 2 minutes to give the server time to come up.
	// Typically we expect only 1 retry will be needed.
	attempt := utils.AttemptStrategy{Delay: 15 * time.Second, Min: 8}
	for a := attempt.Start(); a.Next(); {
		apiState, err = juju.NewAPIState(env, api.DefaultDialOpts())
		if err == nil || errors.Cause(err).Error() != "EOF" {
			break
		}
		progress("bootstrapped instance not ready - attempting to redial")
	}
	if err != nil {
		return fmt.Errorf("cannot connect to bootstrap instance: %v", err)
	}
	progress("restoring bootstrap machine")
	machine0Addr, err := restoreBootstrapMachine(apiState, c.backupFile, agentConf)
	if err != nil {
		return fmt.Errorf("cannot restore bootstrap machine: %v", err)
	}
	progress("restored bootstrap machine")
	// Construct our own state info rather than using juju.NewConn so
	// that we can avoid storage eventual-consistency issues
	// (and it's faster too).
	caCert, ok := cfg.CACert()
	if !ok {
		return fmt.Errorf("configuration has no CA certificate")
	}
	// TODO(dfc) agenConf.Credentials should supply a Tag
	tag, err := names.ParseTag(agentConf.Credentials.Tag)
	if err != nil {
		return err
	}
	progress("opening state")
	// We need to retry here to allow mongo to come up on the restored state server.
	// The connection might succeed due to the mongo dial retries but there may still
	// be a problem issuing database commands.
	var st *state.State
	for a := attempt.Start(); a.Next(); {
		st, err = state.Open(&authentication.MongoInfo{
			Info: mongo.Info{
				Addrs:  []string{fmt.Sprintf("%s:%d", machine0Addr, cfg.StatePort())},
				CACert: caCert,
			},
			Tag:      tag,
			Password: agentConf.Credentials.Password,
		}, mongo.DefaultDialOpts(), environs.NewStatePolicy())
		if err == nil {
			break
		}
		progress("state server not ready - attempting to re-connect")
	}
	if err != nil {
		return fmt.Errorf("cannot open state: %v", err)
	}
	progress("updating all machines")
	if err := updateAllMachines(st, machine0Addr); err != nil {
		return fmt.Errorf("cannot update machines: %v", err)
	}
	return nil
}