func mainDaemon() {
	if utils.ExperimentalBuild() {
		logrus.Warn("Running experimental build")
	}

	if flag.NArg() != 0 {
		flag.Usage()
		return
	}

	logrus.SetFormatter(&logrus.TextFormatter{TimestampFormat: timeutils.RFC3339NanoFixed})

	if err := setDefaultUmask(); err != nil {
		logrus.Fatalf("Failed to set umask: %v", err)
	}

	var pfile *pidfile.PidFile
	if daemonCfg.Pidfile != "" {
		pf, err := pidfile.New(daemonCfg.Pidfile)
		if err != nil {
			logrus.Fatalf("Error starting daemon: %v", err)
		}
		pfile = pf
		defer func() {
			if err := pfile.Remove(); err != nil {
				logrus.Error(err)
			}
		}()
	}

	serverConfig := &apiserver.ServerConfig{
		Logging:     true,
		EnableCors:  daemonCfg.EnableCors,
		CorsHeaders: daemonCfg.CorsHeaders,
		Version:     dockerversion.VERSION,
	}
	serverConfig = setPlatformServerConfig(serverConfig, daemonCfg)

	if *flTls {
		if *flTlsVerify {
			tlsOptions.ClientAuth = tls.RequireAndVerifyClientCert
		}
		tlsConfig, err := tlsconfig.Server(tlsOptions)
		if err != nil {
			logrus.Fatal(err)
		}
		serverConfig.TLSConfig = tlsConfig
	}

	api := apiserver.New(serverConfig)

	// The serve API routine never exits unless an error occurs
	// We need to start it as a goroutine and wait on it so
	// daemon doesn't exit
	serveAPIWait := make(chan error)
	go func() {
		if err := api.ServeApi(flHosts); err != nil {
			logrus.Errorf("ServeAPI error: %v", err)
			serveAPIWait <- err
			return
		}
		serveAPIWait <- nil
	}()

	if err := migrateKey(); err != nil {
		logrus.Fatal(err)
	}
	daemonCfg.TrustKeyPath = *flTrustKey

	registryService := registry.NewService(registryCfg)
	d, err := daemon.NewDaemon(daemonCfg, registryService)
	if err != nil {
		if pfile != nil {
			if err := pfile.Remove(); err != nil {
				logrus.Error(err)
			}
		}
		logrus.Fatalf("Error starting daemon: %v", err)
	}

	logrus.Info("Daemon has completed initialization")

	logrus.WithFields(logrus.Fields{
		"version":     dockerversion.VERSION,
		"commit":      dockerversion.GITCOMMIT,
		"execdriver":  d.ExecutionDriver().Name(),
		"graphdriver": d.GraphDriver().String(),
	}).Info("Docker daemon")

	signal.Trap(func() {
		api.Close()
		<-serveAPIWait
		shutdownDaemon(d, 15)
		if pfile != nil {
			if err := pfile.Remove(); err != nil {
				logrus.Error(err)
			}
		}
	})

//.........这里部分代码省略.........

// CmdDaemon is the daemon command, called the raw arguments after `docker daemon`.
func (cli *DaemonCli) CmdDaemon(args ...string) error {
	if *flDaemon {
		// allow legacy forms `docker -D -d` and `docker -d -D`
		logrus.Warn("please use 'docker daemon' instead.")
	} else if !commonFlags.FlagSet.IsEmpty() || !clientFlags.FlagSet.IsEmpty() {
		// deny `docker -D daemon`
		illegalFlag := getGlobalFlag()
		fmt.Fprintf(os.Stderr, "invalid flag '-%s'.\nSee 'docker daemon --help'.\n", illegalFlag.Names[0])
		os.Exit(1)
	} else {
		// allow new form `docker daemon -D`
		flag.Merge(daemonFlags, commonFlags.FlagSet)
	}

	daemonFlags.ParseFlags(args, true)
	commonFlags.PostParse()

	if len(commonFlags.Hosts) == 0 {
		commonFlags.Hosts = []string{opts.DefaultHost}
	}
	if commonFlags.TrustKey == "" {
		commonFlags.TrustKey = filepath.Join(getDaemonConfDir(), defaultTrustKeyFile)
	}

	if utils.ExperimentalBuild() {
		logrus.Warn("Running experimental build")
	}

	logrus.SetFormatter(&logrus.TextFormatter{TimestampFormat: timeutils.RFC3339NanoFixed})

	if err := setDefaultUmask(); err != nil {
		logrus.Fatalf("Failed to set umask: %v", err)
	}

	if len(cli.LogConfig.Config) > 0 {
		if err := logger.ValidateLogOpts(cli.LogConfig.Type, cli.LogConfig.Config); err != nil {
			logrus.Fatalf("Failed to set log opts: %v", err)
		}
	}

	var pfile *pidfile.PidFile
	if cli.Pidfile != "" {
		pf, err := pidfile.New(cli.Pidfile)
		if err != nil {
			logrus.Fatalf("Error starting daemon: %v", err)
		}
		pfile = pf
		defer func() {
			if err := pfile.Remove(); err != nil {
				logrus.Error(err)
			}
		}()
	}

	if cli.LogConfig.Config == nil {
		cli.LogConfig.Config = make(map[string]string)
	}

	serverConfig := &apiserver.ServerConfig{
		Logging:     true,
		EnableCors:  cli.EnableCors,
		CorsHeaders: cli.CorsHeaders,
		Version:     dockerversion.VERSION,
	}
	serverConfig = setPlatformServerConfig(serverConfig, cli.Config)

	if commonFlags.TLSOptions != nil {
		if !commonFlags.TLSOptions.InsecureSkipVerify {
			// server requires and verifies client's certificate
			commonFlags.TLSOptions.ClientAuth = tls.RequireAndVerifyClientCert
		}
		tlsConfig, err := tlsconfig.Server(*commonFlags.TLSOptions)
		if err != nil {
			logrus.Fatalf("foobar: %v", err)
		}
		serverConfig.TLSConfig = tlsConfig
	}

	api := apiserver.New(serverConfig)

	// The serve API routine never exits unless an error occurs
	// We need to start it as a goroutine and wait on it so
	// daemon doesn't exit
	serveAPIWait := make(chan error)
	go func() {
		if err := api.ServeApi(commonFlags.Hosts); err != nil {
			logrus.Errorf("ServeAPI error: %v", err)
			serveAPIWait <- err
			return
		}
		serveAPIWait <- nil
	}()

	if err := migrateKey(); err != nil {
		logrus.Fatal(err)
	}
	cli.TrustKeyPath = commonFlags.TrustKey

	registryService := registry.NewService(cli.registryOptions)
//.........这里部分代码省略.........