func (s *workerSuite) TestKeyUpdateRetainsExisting(c *gc.C) {
	authWorker := authenticationworker.NewWorker(s.keyupdaterApi, agentConfig(c, s.machine.Tag().(names.MachineTag)))
	defer stop(c, authWorker)

	newKey := sshtesting.ValidKeyThree.Key + " [email protected]"
	s.setAuthorisedKeys(c, newKey)
	newKeyWithCommentPrefix := sshtesting.ValidKeyThree.Key + " Juju:[email protected]"
	s.waitSSHKeys(c, append(s.existingKeys, newKeyWithCommentPrefix))
}

func (s *workerSuite) TestWorkerRestart(c *gc.C) {
	authWorker := authenticationworker.NewWorker(s.keyupdaterApi, agentConfig(c, s.machine.Tag().(names.MachineTag)))
	defer stop(c, authWorker)
	s.waitSSHKeys(c, append(s.existingKeys, s.existingEnvKey))

	// Stop the worker and delete and add keys from the environment while it is down.
	// added: key 3
	// deleted: key 1 (existing env key)
	stop(c, authWorker)
	s.setAuthorisedKeys(c, sshtesting.ValidKeyThree.Key+" [email protected]")

	// Restart the worker and check that the ssh auth keys are as expected.
	authWorker = authenticationworker.NewWorker(s.keyupdaterApi, agentConfig(c, s.machine.Tag().(names.MachineTag)))
	defer stop(c, authWorker)

	yetAnotherKeyWithCommentPrefix := sshtesting.ValidKeyThree.Key + " Juju:[email protected]"
	s.waitSSHKeys(c, append(s.existingKeys, yetAnotherKeyWithCommentPrefix))
}

func (s *workerSuite) TestNewKeysInJujuAreSavedOnStartup(c *gc.C) {
	newKey := sshtesting.ValidKeyThree.Key + " [email protected]"
	s.setAuthorisedKeys(c, newKey)

	authWorker := authenticationworker.NewWorker(s.keyupdaterApi, agentConfig(c, s.machine.Tag()))
	defer stop(c, authWorker)

	newKeyWithCommentPrefix := sshtesting.ValidKeyThree.Key + " Juju:[email protected]"
	s.waitSSHKeys(c, append(s.existingKeys, newKeyWithCommentPrefix))
}

func (s *workerSuite) TestMultipleChanges(c *gc.C) {
	authWorker := authenticationworker.NewWorker(s.keyupdaterApi, agentConfig(c, s.machine.Tag().(names.MachineTag)))
	defer stop(c, authWorker)
	s.waitSSHKeys(c, append(s.existingKeys, s.existingEnvKey))

	// Perform a set to add a key and delete a key.
	// added: key 3
	// deleted: key 1 (existing env key)
	s.setAuthorisedKeys(c, sshtesting.ValidKeyThree.Key+" [email protected]")
	yetAnotherKeyWithComment := sshtesting.ValidKeyThree.Key + " Juju:[email protected]"
	s.waitSSHKeys(c, append(s.existingKeys, yetAnotherKeyWithComment))
}

func (s *workerSuite) TestDeleteKey(c *gc.C) {
	authWorker := authenticationworker.NewWorker(s.keyupdaterApi, agentConfig(c, s.machine.Tag().(names.MachineTag)))
	defer stop(c, authWorker)

	// Add another key
	anotherKey := sshtesting.ValidKeyThree.Key + " [email protected]"
	s.setAuthorisedKeys(c, s.existingEnvKey, anotherKey)
	anotherKeyWithCommentPrefix := sshtesting.ValidKeyThree.Key + " Juju:[email protected]"
	s.waitSSHKeys(c, append(s.existingKeys, s.existingEnvKey, anotherKeyWithCommentPrefix))

	// Delete the original key and check anotherKey plus the existing keys remain.
	s.setAuthorisedKeys(c, anotherKey)
	s.waitSSHKeys(c, append(s.existingKeys, anotherKeyWithCommentPrefix))
}

//.........这里部分代码省略.........

	// Before starting any workers, ensure we record the Juju version this machine
	// agent is running.
	currentTools := &coretools.Tools{Version: version.Current}
	if err := st.Upgrader().SetVersion(agentConfig.Tag().String(), currentTools.Version); err != nil {
		return nil, errors.Annotate(err, "cannot set machine agent version")
	}

	providerType := agentConfig.Value(agent.ProviderType)

	// Run the upgrader and the upgrade-steps worker without waiting for
	// the upgrade steps to complete.
	runner.StartWorker("upgrader", func() (worker.Worker, error) {
		return upgrader.NewUpgrader(
			st.Upgrader(),
			agentConfig,
			a.previousAgentVersion,
			a.upgradeWorkerContext.IsUpgradeRunning,
		), nil
	})
	runner.StartWorker("upgrade-steps", func() (worker.Worker, error) {
		return a.upgradeWorkerContext.Worker(a, st, entity.Jobs()), nil
	})

	// All other workers must wait for the upgrade steps to complete
	// before starting.
	a.startWorkerAfterUpgrade(runner, "machiner", func() (worker.Worker, error) {
		return machiner.NewMachiner(st.Machiner(), agentConfig), nil
	})
	a.startWorkerAfterUpgrade(runner, "apiaddressupdater", func() (worker.Worker, error) {
		return apiaddressupdater.NewAPIAddressUpdater(st.Machiner(), a), nil
	})
	a.startWorkerAfterUpgrade(runner, "logger", func() (worker.Worker, error) {
		return workerlogger.NewLogger(st.Logger(), agentConfig), nil
	})
	a.startWorkerAfterUpgrade(runner, "machineenvironmentworker", func() (worker.Worker, error) {
		return machineenvironmentworker.NewMachineEnvironmentWorker(st.Environment(), agentConfig), nil
	})
	a.startWorkerAfterUpgrade(runner, "rsyslog", func() (worker.Worker, error) {
		return newRsyslogConfigWorker(st.Rsyslog(), agentConfig, rsyslogMode)
	})
	// TODO (mfoord 8/8/2014) improve the way we detect networking capabilities. Bug lp:1354365
	writeNetworkConfig := providerType == "maas"
	if disableNetworkManagement || !writeNetworkConfig {
		a.startWorkerAfterUpgrade(runner, "networker", func() (worker.Worker, error) {
			return newSafeNetworker(st.Networker(), agentConfig, networker.DefaultConfigDir)
		})
	} else if !disableNetworkManagement && writeNetworkConfig {
		a.startWorkerAfterUpgrade(runner, "networker", func() (worker.Worker, error) {
			return newNetworker(st.Networker(), agentConfig, networker.DefaultConfigDir)
		})
	}

	// If not a local provider bootstrap machine, start the worker to
	// manage SSH keys.
	if providerType != provider.Local || a.MachineId != bootstrapMachineId {
		a.startWorkerAfterUpgrade(runner, "authenticationworker", func() (worker.Worker, error) {
			return authenticationworker.NewWorker(st.KeyUpdater(), agentConfig), nil
		})
	}

	// Perform the operations needed to set up hosting for containers.
	if err := a.setupContainerSupport(runner, st, entity, agentConfig); err != nil {
		cause := errors.Cause(err)
		if params.IsCodeDead(cause) || cause == worker.ErrTerminateAgent {
			return nil, worker.ErrTerminateAgent
		}
		return nil, fmt.Errorf("setting up container support: %v", err)
	}
	for _, job := range entity.Jobs() {
		switch job {
		case params.JobHostUnits:
			a.startWorkerAfterUpgrade(runner, "deployer", func() (worker.Worker, error) {
				apiDeployer := st.Deployer()
				context := newDeployContext(apiDeployer, agentConfig)
				return deployer.NewDeployer(apiDeployer, context), nil
			})
		case params.JobManageEnviron:
			a.startWorkerAfterUpgrade(singularRunner, "environ-provisioner", func() (worker.Worker, error) {
				return provisioner.NewEnvironProvisioner(st.Provisioner(), agentConfig), nil
			})
			// TODO(axw) 2013-09-24 bug #1229506
			// Make another job to enable the firewaller. Not all
			// environments are capable of managing ports
			// centrally.
			a.startWorkerAfterUpgrade(singularRunner, "firewaller", func() (worker.Worker, error) {
				return firewaller.NewFirewaller(st.Firewaller())
			})
			a.startWorkerAfterUpgrade(singularRunner, "charm-revision-updater", func() (worker.Worker, error) {
				return charmrevisionworker.NewRevisionUpdateWorker(st.CharmRevisionUpdater()), nil
			})
		case params.JobManageStateDeprecated:
			// Legacy environments may set this, but we ignore it.
		default:
			// TODO(dimitern): Once all workers moved over to using
			// the API, report "unknown job type" here.
		}
	}
	return newCloseWorker(runner, st), nil // Note: a worker.Runner is itself a worker.Worker.
}