func (s *MongoSuite) TestGenerateSharedSecret(c *gc.C) {
	secret, err := mongo.GenerateSharedSecret()
	c.Assert(err, jc.ErrorIsNil)
	c.Assert(secret, gc.HasLen, 1024)
	_, err = base64.StdEncoding.DecodeString(secret)
	c.Assert(err, jc.ErrorIsNil)
}

// Run initializes state for an environment.
func (c *BootstrapCommand) Run(_ *cmd.Context) error {
	envCfg, err := config.New(config.NoDefaults, c.ControllerModelConfig)
	if err != nil {
		return err
	}
	err = c.ReadConfig("machine-0")
	if err != nil {
		return err
	}
	agentConfig := c.CurrentConfig()
	network.SetPreferIPv6(agentConfig.PreferIPv6())

	// agent.Jobs is an optional field in the agent config, and was
	// introduced after 1.17.2. We default to allowing units on
	// machine-0 if missing.
	jobs := agentConfig.Jobs()
	if len(jobs) == 0 {
		jobs = []multiwatcher.MachineJob{
			multiwatcher.JobManageModel,
			multiwatcher.JobHostUnits,
			multiwatcher.JobManageNetworking,
		}
	}

	// Get the bootstrap machine's addresses from the provider.
	env, err := environs.New(envCfg)
	if err != nil {
		return err
	}
	newConfigAttrs := make(map[string]interface{})

	// Check to see if a newer agent version has been requested
	// by the bootstrap client.
	desiredVersion, ok := envCfg.AgentVersion()
	if ok && desiredVersion != jujuversion.Current {
		// If we have been asked for a newer version, ensure the newer
		// tools can actually be found, or else bootstrap won't complete.
		stream := envtools.PreferredStream(&desiredVersion, envCfg.Development(), envCfg.AgentStream())
		logger.Infof("newer tools requested, looking for %v in stream %v", desiredVersion, stream)
		filter := tools.Filter{
			Number: desiredVersion,
			Arch:   arch.HostArch(),
			Series: series.HostSeries(),
		}
		_, toolsErr := envtools.FindTools(env, -1, -1, stream, filter)
		if toolsErr == nil {
			logger.Infof("tools are available, upgrade will occur after bootstrap")
		}
		if errors.IsNotFound(toolsErr) {
			// Newer tools not available, so revert to using the tools
			// matching the current agent version.
			logger.Warningf("newer tools for %q not available, sticking with version %q", desiredVersion, jujuversion.Current)
			newConfigAttrs["agent-version"] = jujuversion.Current.String()
		} else if toolsErr != nil {
			logger.Errorf("cannot find newer tools: %v", toolsErr)
			return toolsErr
		}
	}

	instanceId := instance.Id(c.InstanceId)
	instances, err := env.Instances([]instance.Id{instanceId})
	if err != nil {
		return err
	}
	addrs, err := instances[0].Addresses()
	if err != nil {
		return err
	}

	// When machine addresses are reported from state, they have
	// duplicates removed.  We should do the same here so that
	// there is not unnecessary churn in the mongo replicaset.
	// TODO (cherylj) Add explicit unit tests for this - tracked
	// by bug #1544158.
	addrs = network.MergedAddresses([]network.Address{}, addrs)

	// Generate a private SSH key for the controllers, and add
	// the public key to the environment config. We'll add the
	// private key to StateServingInfo below.
	privateKey, publicKey, err := sshGenerateKey(config.JujuSystemKey)
	if err != nil {
		return errors.Annotate(err, "failed to generate system key")
	}
	authorizedKeys := config.ConcatAuthKeys(envCfg.AuthorizedKeys(), publicKey)
	newConfigAttrs[config.AuthKeysConfig] = authorizedKeys

	// Generate a shared secret for the Mongo replica set, and write it out.
	sharedSecret, err := mongo.GenerateSharedSecret()
	if err != nil {
		return err
	}
	info, ok := agentConfig.StateServingInfo()
	if !ok {
		return fmt.Errorf("bootstrap machine config has no state serving info")
	}
	info.SharedSecret = sharedSecret
	info.SystemIdentity = privateKey
	err = c.ChangeConfig(func(agentConfig agent.ConfigSetter) error {
		agentConfig.SetStateServingInfo(info)
//.........这里部分代码省略.........

// Run initializes state for an environment.
func (c *BootstrapCommand) Run(_ *cmd.Context) error {
	envCfg, err := config.New(config.NoDefaults, c.EnvConfig)
	if err != nil {
		return err
	}
	err = c.ReadConfig("machine-0")
	if err != nil {
		return err
	}
	agentConfig := c.CurrentConfig()
	network.InitializeFromConfig(agentConfig)

	// agent.Jobs is an optional field in the agent config, and was
	// introduced after 1.17.2. We default to allowing units on
	// machine-0 if missing.
	jobs := agentConfig.Jobs()
	if len(jobs) == 0 {
		jobs = []multiwatcher.MachineJob{
			multiwatcher.JobManageEnviron,
			multiwatcher.JobHostUnits,
			multiwatcher.JobManageNetworking,
		}
	}

	// Get the bootstrap machine's addresses from the provider.
	env, err := environs.New(envCfg)
	if err != nil {
		return err
	}
	instanceId := instance.Id(c.InstanceId)
	instances, err := env.Instances([]instance.Id{instanceId})
	if err != nil {
		return err
	}
	addrs, err := instances[0].Addresses()
	if err != nil {
		return err
	}

	// Generate a private SSH key for the state servers, and add
	// the public key to the environment config. We'll add the
	// private key to StateServingInfo below.
	privateKey, publicKey, err := sshGenerateKey(config.JujuSystemKey)
	if err != nil {
		return errors.Annotate(err, "failed to generate system key")
	}
	authorizedKeys := config.ConcatAuthKeys(envCfg.AuthorizedKeys(), publicKey)
	envCfg, err = env.Config().Apply(map[string]interface{}{
		config.AuthKeysConfig: authorizedKeys,
	})
	if err != nil {
		return errors.Annotate(err, "failed to add public key to environment config")
	}

	// Generate a shared secret for the Mongo replica set, and write it out.
	sharedSecret, err := mongo.GenerateSharedSecret()
	if err != nil {
		return err
	}
	info, ok := agentConfig.StateServingInfo()
	if !ok {
		return fmt.Errorf("bootstrap machine config has no state serving info")
	}
	info.SharedSecret = sharedSecret
	info.SystemIdentity = privateKey
	err = c.ChangeConfig(func(agentConfig agent.ConfigSetter) error {
		agentConfig.SetStateServingInfo(info)
		return nil
	})
	if err != nil {
		return fmt.Errorf("cannot write agent config: %v", err)
	}
	agentConfig = c.CurrentConfig()

	// Create system-identity file
	if err := agent.WriteSystemIdentityFile(agentConfig); err != nil {
		return err
	}

	if err := c.startMongo(addrs, agentConfig); err != nil {
		return err
	}

	logger.Infof("started mongo")
	// Initialise state, and store any agent config (e.g. password) changes.
	var st *state.State
	var m *state.Machine
	err = c.ChangeConfig(func(agentConfig agent.ConfigSetter) error {
		var stateErr error
		dialOpts := mongo.DefaultDialOpts()

		// Set a longer socket timeout than usual, as the machine
		// will be starting up and disk I/O slower than usual. This
		// has been known to cause timeouts in queries.
		timeouts := envCfg.BootstrapSSHOpts()
		dialOpts.SocketTimeout = timeouts.Timeout
		if dialOpts.SocketTimeout < minSocketTimeout {
			dialOpts.SocketTimeout = minSocketTimeout
		}
//.........这里部分代码省略.........

// ensureMongoServer ensures that mongo is installed and running,
// and ready for opening a state connection.
func (a *MachineAgent) ensureMongoServer(agentConfig agent.Config) (err error) {
	a.mongoInitMutex.Lock()
	defer a.mongoInitMutex.Unlock()
	if a.mongoInitialized {
		logger.Debugf("mongo is already initialized")
		return nil
	}
	defer func() {
		if err == nil {
			a.mongoInitialized = true
		}
	}()

	servingInfo, ok := agentConfig.StateServingInfo()
	if !ok {
		return fmt.Errorf("state worker was started with no state serving info")
	}

	// When upgrading from a pre-HA-capable environment,
	// we must add machine-0 to the admin database and
	// initiate its replicaset.
	//
	// TODO(axw) remove this when we no longer need
	// to upgrade from pre-HA-capable environments.
	var shouldInitiateMongoServer bool
	var addrs []network.Address
	if isPreHAVersion(a.previousAgentVersion) {
		_, err := a.ensureMongoAdminUser(agentConfig)
		if err != nil {
			return err
		}
		if servingInfo.SharedSecret == "" {
			servingInfo.SharedSecret, err = mongo.GenerateSharedSecret()
			if err != nil {
				return err
			}
			if err = a.ChangeConfig(func(config agent.ConfigSetter) error {
				config.SetStateServingInfo(servingInfo)
				return nil
			}); err != nil {
				return err
			}
			agentConfig = a.CurrentConfig()
		}
		// Note: we set Direct=true in the mongo options because it's
		// possible that we've previously upgraded the mongo server's
		// configuration to form a replicaset, but failed to initiate it.
		st, m, err := openState(agentConfig, mongo.DialOpts{Direct: true})
		if err != nil {
			return err
		}
		ssi := paramsStateServingInfoToStateStateServingInfo(servingInfo)
		if err := st.SetStateServingInfo(ssi); err != nil {
			st.Close()
			return fmt.Errorf("cannot set state serving info: %v", err)
		}
		st.Close()
		addrs = m.Addresses()
		shouldInitiateMongoServer = true
	}

	// ensureMongoServer installs/upgrades the upstart config as necessary.
	ensureServerParams, err := newEnsureServerParams(agentConfig)
	if err != nil {
		return err
	}
	if err := ensureMongoServer(ensureServerParams); err != nil {
		return err
	}
	if !shouldInitiateMongoServer {
		return nil
	}

	// Initiate the replicaset for upgraded environments.
	//
	// TODO(axw) remove this when we no longer need
	// to upgrade from pre-HA-capable environments.
	stateInfo, ok := agentConfig.MongoInfo()
	if !ok {
		return fmt.Errorf("state worker was started with no state serving info")
	}
	dialInfo, err := mongo.DialInfo(stateInfo.Info, mongo.DefaultDialOpts())
	if err != nil {
		return err
	}
	peerAddr := mongo.SelectPeerAddress(addrs)
	if peerAddr == "" {
		return fmt.Errorf("no appropriate peer address found in %q", addrs)
	}
	if err := maybeInitiateMongoServer(peergrouper.InitiateMongoParams{
		DialInfo:       dialInfo,
		MemberHostPort: net.JoinHostPort(peerAddr, fmt.Sprint(servingInfo.StatePort)),
		// TODO(dfc) InitiateMongoParams should take a Tag
		User:     stateInfo.Tag.String(),
		Password: stateInfo.Password,
	}); err != nil {
		return err
	}
//.........这里部分代码省略.........

// Run initializes state for an environment.
func (c *BootstrapCommand) Run(_ *cmd.Context) error {
	envCfg, err := config.New(config.NoDefaults, c.EnvConfig)
	if err != nil {
		return err
	}
	err = c.ReadConfig("machine-0")
	if err != nil {
		return err
	}
	agentConfig := c.CurrentConfig()

	// agent.Jobs is an optional field in the agent config, and was
	// introduced after 1.17.2. We default to allowing units on
	// machine-0 if missing.
	jobs := agentConfig.Jobs()
	if len(jobs) == 0 {
		jobs = []params.MachineJob{
			params.JobManageEnviron,
			params.JobHostUnits,
		}
	}

	// Get the bootstrap machine's addresses from the provider.
	env, err := environs.New(envCfg)
	if err != nil {
		return err
	}
	instanceId := instance.Id(c.InstanceId)
	instances, err := env.Instances([]instance.Id{instanceId})
	if err != nil {
		return err
	}
	addrs, err := instances[0].Addresses()
	if err != nil {
		return err
	}

	// Create system-identity file
	if err := agent.WriteSystemIdentityFile(agentConfig); err != nil {
		return err
	}

	// Generate a shared secret for the Mongo replica set, and write it out.
	sharedSecret, err := mongo.GenerateSharedSecret()
	if err != nil {
		return err
	}
	info, ok := agentConfig.StateServingInfo()
	if !ok {
		return fmt.Errorf("bootstrap machine config has no state serving info")
	}
	info.SharedSecret = sharedSecret
	err = c.ChangeConfig(func(agentConfig agent.ConfigSetter) {
		agentConfig.SetStateServingInfo(info)
	})
	if err != nil {
		return fmt.Errorf("cannot write agent config: %v", err)
	}
	agentConfig = c.CurrentConfig()

	if err := c.startMongo(addrs, agentConfig); err != nil {
		return err
	}

	logger.Infof("started mongo")
	// Initialise state, and store any agent config (e.g. password) changes.
	var st *state.State
	var m *state.Machine
	err = nil
	writeErr := c.ChangeConfig(func(agentConfig agent.ConfigSetter) {
		st, m, err = agent.InitializeState(
			agentConfig,
			envCfg,
			agent.BootstrapMachineConfig{
				Addresses:       addrs,
				Constraints:     c.Constraints,
				Jobs:            jobs,
				InstanceId:      instanceId,
				Characteristics: c.Hardware,
				SharedSecret:    sharedSecret,
			},
			mongo.DefaultDialOpts(),
			environs.NewStatePolicy(),
		)
	})
	if writeErr != nil {
		return fmt.Errorf("cannot write initial configuration: %v", err)
	}
	if err != nil {
		return err
	}
	defer st.Close()

	// bootstrap machine always gets the vote
	return m.SetHasVote(true)
}

// ensureMongoServer ensures that mongo is installed and running,
// and ready for opening a state connection.
func (a *MachineAgent) ensureMongoServer(agentConfig agent.Config) error {
	servingInfo, ok := agentConfig.StateServingInfo()
	if !ok {
		return fmt.Errorf("state worker was started with no state serving info")
	}
	namespace := agentConfig.Value(agent.Namespace)

	// When upgrading from a pre-HA-capable environment,
	// we must add machine-0 to the admin database and
	// initiate its replicaset.
	//
	// TODO(axw) remove this when we no longer need
	// to upgrade from pre-HA-capable environments.
	var shouldInitiateMongoServer bool
	var addrs []network.Address
	if isPreHAVersion(agentConfig.UpgradedToVersion()) {
		_, err := a.ensureMongoAdminUser(agentConfig)
		if err != nil {
			return err
		}
		if servingInfo.SharedSecret == "" {
			servingInfo.SharedSecret, err = mongo.GenerateSharedSecret()
			if err != nil {
				return err
			}
			if err = a.ChangeConfig(func(config agent.ConfigSetter) {
				config.SetStateServingInfo(servingInfo)
			}); err != nil {
				return err
			}
			agentConfig = a.CurrentConfig()
		}
		st, m, err := openState(agentConfig)
		if err != nil {
			return err
		}
		if err := st.SetStateServingInfo(servingInfo); err != nil {
			st.Close()
			return fmt.Errorf("cannot set state serving info: %v", err)
		}
		st.Close()
		addrs = m.Addresses()
		shouldInitiateMongoServer = true
	}

	// ensureMongoServer installs/upgrades the upstart config as necessary.
	if err := ensureMongoServer(
		agentConfig.DataDir(),
		namespace,
		servingInfo,
	); err != nil {
		return err
	}
	if !shouldInitiateMongoServer {
		return nil
	}

	// Initiate the replicaset for upgraded environments.
	//
	// TODO(axw) remove this when we no longer need
	// to upgrade from pre-HA-capable environments.
	stateInfo, ok := agentConfig.StateInfo()
	if !ok {
		return fmt.Errorf("state worker was started with no state serving info")
	}
	dialInfo, err := mongo.DialInfo(stateInfo.Info, mongo.DefaultDialOpts())
	if err != nil {
		return err
	}
	peerAddr := mongo.SelectPeerAddress(addrs)
	if peerAddr == "" {
		return fmt.Errorf("no appropriate peer address found in %q", addrs)
	}
	return maybeInitiateMongoServer(peergrouper.InitiateMongoParams{
		DialInfo:       dialInfo,
		MemberHostPort: net.JoinHostPort(peerAddr, fmt.Sprint(servingInfo.StatePort)),
		User:           stateInfo.Tag,
		Password:       stateInfo.Password,
	})
}