moby--moby/cmd/dockerd/daemon.go

package main

import (
	"context"
	"crypto/tls"
	"fmt"
	"os"
	"path/filepath"
	"runtime"
	"strings"
	"time"

	containerddefaults "github.com/containerd/containerd/defaults"
	"github.com/docker/distribution/uuid"
	"github.com/docker/docker/api"
	apiserver "github.com/docker/docker/api/server"
	buildbackend "github.com/docker/docker/api/server/backend/build"
	"github.com/docker/docker/api/server/middleware"
	"github.com/docker/docker/api/server/router"
	"github.com/docker/docker/api/server/router/build"
	checkpointrouter "github.com/docker/docker/api/server/router/checkpoint"
	"github.com/docker/docker/api/server/router/container"
	distributionrouter "github.com/docker/docker/api/server/router/distribution"
	grpcrouter "github.com/docker/docker/api/server/router/grpc"
	"github.com/docker/docker/api/server/router/image"
	"github.com/docker/docker/api/server/router/network"
	pluginrouter "github.com/docker/docker/api/server/router/plugin"
	sessionrouter "github.com/docker/docker/api/server/router/session"
	swarmrouter "github.com/docker/docker/api/server/router/swarm"
	systemrouter "github.com/docker/docker/api/server/router/system"
	"github.com/docker/docker/api/server/router/volume"
	buildkit "github.com/docker/docker/builder/builder-next"
	"github.com/docker/docker/builder/dockerfile"
	"github.com/docker/docker/builder/fscache"
	"github.com/docker/docker/cli/debug"
	"github.com/docker/docker/daemon"
	"github.com/docker/docker/daemon/cluster"
	"github.com/docker/docker/daemon/config"
	"github.com/docker/docker/daemon/listeners"
	"github.com/docker/docker/dockerversion"
	"github.com/docker/docker/libcontainerd/supervisor"
	dopts "github.com/docker/docker/opts"
	"github.com/docker/docker/pkg/authorization"
	"github.com/docker/docker/pkg/homedir"
	"github.com/docker/docker/pkg/jsonmessage"
	"github.com/docker/docker/pkg/pidfile"
	"github.com/docker/docker/pkg/plugingetter"
	"github.com/docker/docker/pkg/signal"
	"github.com/docker/docker/pkg/system"
	"github.com/docker/docker/plugin"
	"github.com/docker/docker/rootless"
	"github.com/docker/docker/runconfig"
	"github.com/docker/go-connections/tlsconfig"
	swarmapi "github.com/docker/swarmkit/api"
	"github.com/moby/buildkit/session"
	"github.com/pkg/errors"
	"github.com/sirupsen/logrus"
	"github.com/spf13/pflag"
)

// DaemonCli represents the daemon CLI.
type DaemonCli struct {
	*config.Config
	configFile *string
	flags      *pflag.FlagSet

	api             *apiserver.Server
	d               *daemon.Daemon
	authzMiddleware *authorization.Middleware // authzMiddleware enables to dynamically reload the authorization plugins
}

// NewDaemonCli returns a daemon CLI
func NewDaemonCli() *DaemonCli {
	return &DaemonCli{}
}

func (cli *DaemonCli) start(opts *daemonOptions) (err error) {
	stopc := make(chan bool)
	defer close(stopc)

	// warn from uuid package when running the daemon
	uuid.Loggerf = logrus.Warnf

	opts.SetDefaultOptions(opts.flags)

	if cli.Config, err = loadDaemonCliConfig(opts); err != nil {
		return err
	}

	if err := configureDaemonLogs(cli.Config); err != nil {
		return err
	}

	logrus.Info("Starting up")

	cli.configFile = &opts.configFile
	cli.flags = opts.flags

	if cli.Config.Debug {
		debug.Enable()
	}

	if cli.Config.Experimental {
		logrus.Warn("Running experimental build")
		if cli.Config.IsRootless() {
			logrus.Warn("Running in rootless mode. Cgroups, AppArmor, and CRIU are disabled.")
		}
		if rootless.RunningWithRootlessKit() {
			logrus.Info("Running with RootlessKit integration")
			if !cli.Config.IsRootless() {
				return fmt.Errorf("rootless mode needs to be enabled for running with RootlessKit")
			}
		}
	} else {
		if cli.Config.IsRootless() {
			return fmt.Errorf("rootless mode is supported only when running in experimental mode")
		}
	}
	// return human-friendly error before creating files
	if runtime.GOOS == "linux" && os.Geteuid() != 0 {
		return fmt.Errorf("dockerd needs to be started with root. To see how to run dockerd in rootless mode with unprivileged user, see the documentation")
	}

	system.InitLCOW(cli.Config.Experimental)

	if err := setDefaultUmask(); err != nil {
		return err
	}

	// Create the daemon root before we create ANY other files (PID, or migrate keys)
	// to ensure the appropriate ACL is set (particularly relevant on Windows)
	if err := daemon.CreateDaemonRoot(cli.Config); err != nil {
		return err
	}

	if err := system.MkdirAll(cli.Config.ExecRoot, 0700, ""); err != nil {
		return err
	}

	potentiallyUnderRuntimeDir := []string{cli.Config.ExecRoot}

	if cli.Pidfile != "" {
		pf, err := pidfile.New(cli.Pidfile)
		if err != nil {
			return errors.Wrap(err, "failed to start daemon")
		}
		potentiallyUnderRuntimeDir = append(potentiallyUnderRuntimeDir, cli.Pidfile)
		defer func() {
			if err := pf.Remove(); err != nil {
				logrus.Error(err)
			}
		}()
	}

	if cli.Config.IsRootless() {
		// Set sticky bit if XDG_RUNTIME_DIR is set && the file is actually under XDG_RUNTIME_DIR
		if _, err := homedir.StickRuntimeDirContents(potentiallyUnderRuntimeDir); err != nil {
			// StickRuntimeDirContents returns nil error if XDG_RUNTIME_DIR is just unset
			logrus.WithError(err).Warn("cannot set sticky bit on files under XDG_RUNTIME_DIR")
		}
	}

	serverConfig, err := newAPIServerConfig(cli)
	if err != nil {
		return errors.Wrap(err, "failed to create API server")
	}
	cli.api = apiserver.New(serverConfig)

	hosts, err := loadListeners(cli, serverConfig)
	if err != nil {
		return errors.Wrap(err, "failed to load listeners")
	}

	ctx, cancel := context.WithCancel(context.Background())
	waitForContainerDShutdown, err := cli.initContainerD(ctx)
	if waitForContainerDShutdown != nil {
		defer waitForContainerDShutdown(10 * time.Second)
	}
	if err != nil {
		cancel()
		return err
	}
	defer cancel()

	signal.Trap(func() {
		cli.stop()
		<-stopc // wait for daemonCli.start() to return
	}, logrus.StandardLogger())

	// Notify that the API is active, but before daemon is set up.
	preNotifySystem()

	pluginStore := plugin.NewStore()

	if err := cli.initMiddlewares(cli.api, serverConfig, pluginStore); err != nil {
		logrus.Fatalf("Error creating middlewares: %v", err)
	}

	d, err := daemon.NewDaemon(ctx, cli.Config, pluginStore)
	if err != nil {
		return errors.Wrap(err, "failed to start daemon")
	}

	d.StoreHosts(hosts)

	// validate after NewDaemon has restored enabled plugins. Don't change order.
	if err := validateAuthzPlugins(cli.Config.AuthorizationPlugins, pluginStore); err != nil {
		return errors.Wrap(err, "failed to validate authorization plugin")
	}

	// TODO: move into startMetricsServer()
	if cli.Config.MetricsAddress != "" {
		if !d.HasExperimental() {
			return errors.Wrap(err, "metrics-addr is only supported when experimental is enabled")
		}
		if err := startMetricsServer(cli.Config.MetricsAddress); err != nil {
			return err
		}
	}

	c, err := createAndStartCluster(cli, d)
	if err != nil {
		logrus.Fatalf("Error starting cluster component: %v", err)
	}

	// Restart all autostart containers which has a swarm endpoint
	// and is not yet running now that we have successfully
	// initialized the cluster.
	d.RestartSwarmContainers()

	logrus.Info("Daemon has completed initialization")

	cli.d = d

	routerOptions, err := newRouterOptions(cli.Config, d)
	if err != nil {
		return err
	}
	routerOptions.api = cli.api
	routerOptions.cluster = c

	initRouter(routerOptions)

	go d.ProcessClusterNotifications(ctx, c.GetWatchStream())

	cli.setupConfigReloadTrap()

	// 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 cli.api.Wait(serveAPIWait)

	// after the daemon is done setting up we can notify systemd api
	notifySystem()

	// Daemon is fully initialized and handling API traffic
	// Wait for serve API to complete
	errAPI := <-serveAPIWait
	c.Cleanup()

	shutdownDaemon(d)

	// Stop notification processing and any background processes
	cancel()

	if errAPI != nil {
		return errors.Wrap(errAPI, "shutting down due to ServeAPI error")
	}

	logrus.Info("Daemon shutdown complete")
	return nil
}

type routerOptions struct {
	sessionManager *session.Manager
	buildBackend   *buildbackend.Backend
	buildCache     *fscache.FSCache // legacy
	features       *map[string]bool
	buildkit       *buildkit.Builder
	daemon         *daemon.Daemon
	api            *apiserver.Server
	cluster        *cluster.Cluster
}

func newRouterOptions(config *config.Config, d *daemon.Daemon) (routerOptions, error) {
	opts := routerOptions{}
	sm, err := session.NewManager()
	if err != nil {
		return opts, errors.Wrap(err, "failed to create sessionmanager")
	}

	builderStateDir := filepath.Join(config.Root, "builder")

	buildCache, err := fscache.NewFSCache(fscache.Opt{
		Backend: fscache.NewNaiveCacheBackend(builderStateDir),
		Root:    builderStateDir,
		GCPolicy: fscache.GCPolicy{ // TODO: expose this in config
			MaxSize:         1024 * 1024 * 512,  // 512MB
			MaxKeepDuration: 7 * 24 * time.Hour, // 1 week
		},
	})
	if err != nil {
		return opts, errors.Wrap(err, "failed to create fscache")
	}

	manager, err := dockerfile.NewBuildManager(d.BuilderBackend(), sm, buildCache, d.IdentityMapping())
	if err != nil {
		return opts, err
	}
	cgroupParent := newCgroupParent(config)
	bk, err := buildkit.New(buildkit.Opt{
		SessionManager:      sm,
		Root:                filepath.Join(config.Root, "buildkit"),
		Dist:                d.DistributionServices(),
		NetworkController:   d.NetworkController(),
		DefaultCgroupParent: cgroupParent,
		ResolverOpt:         d.NewResolveOptionsFunc(),
		BuilderConfig:       config.Builder,
		Rootless:            d.Rootless(),
		IdentityMapping:     d.IdentityMapping(),
		DNSConfig:           config.DNSConfig,
	})
	if err != nil {
		return opts, err
	}

	bb, err := buildbackend.NewBackend(d.ImageService(), manager, buildCache, bk)
	if err != nil {
		return opts, errors.Wrap(err, "failed to create buildmanager")
	}
	return routerOptions{
		sessionManager: sm,
		buildBackend:   bb,
		buildCache:     buildCache,
		buildkit:       bk,
		features:       d.Features(),
		daemon:         d,
	}, nil
}

func (cli *DaemonCli) reloadConfig() {
	reload := func(c *config.Config) {

		// Revalidate and reload the authorization plugins
		if err := validateAuthzPlugins(c.AuthorizationPlugins, cli.d.PluginStore); err != nil {
			logrus.Fatalf("Error validating authorization plugin: %v", err)
			return
		}
		cli.authzMiddleware.SetPlugins(c.AuthorizationPlugins)

		// The namespaces com.docker.*, io.docker.*, org.dockerproject.* have been documented
		// to be reserved for Docker's internal use, but this was never enforced.  Allowing
		// configured labels to use these namespaces are deprecated for 18.05.
		//
		// The following will check the usage of such labels, and report a warning for deprecation.
		//
		// TODO: At the next stable release, the validation should be folded into the other
		// configuration validation functions and an error will be returned instead, and this
		// block should be deleted.
		if err := config.ValidateReservedNamespaceLabels(c.Labels); err != nil {
			logrus.Warnf("Configured labels using reserved namespaces is deprecated: %s", err)
		}

		if err := cli.d.Reload(c); err != nil {
			logrus.Errorf("Error reconfiguring the daemon: %v", err)
			return
		}

		if c.IsValueSet("debug") {
			debugEnabled := debug.IsEnabled()
			switch {
			case debugEnabled && !c.Debug: // disable debug
				debug.Disable()
			case c.Debug && !debugEnabled: // enable debug
				debug.Enable()
			}
		}
	}

	if err := config.Reload(*cli.configFile, cli.flags, reload); err != nil {
		logrus.Error(err)
	}
}

func (cli *DaemonCli) stop() {
	cli.api.Close()
}

// shutdownDaemon just wraps daemon.Shutdown() to handle a timeout in case
// d.Shutdown() is waiting too long to kill container or worst it's
// blocked there
func shutdownDaemon(d *daemon.Daemon) {
	shutdownTimeout := d.ShutdownTimeout()
	ch := make(chan struct{})
	go func() {
		d.Shutdown()
		close(ch)
	}()
	if shutdownTimeout < 0 {
		<-ch
		logrus.Debug("Clean shutdown succeeded")
		return
	}

	timeout := time.NewTimer(time.Duration(shutdownTimeout) * time.Second)
	defer timeout.Stop()

	select {
	case <-ch:
		logrus.Debug("Clean shutdown succeeded")
	case <-timeout.C:
		logrus.Error("Force shutdown daemon")
	}
}

func loadDaemonCliConfig(opts *daemonOptions) (*config.Config, error) {
	conf := opts.daemonConfig
	flags := opts.flags
	conf.Debug = opts.Debug
	conf.Hosts = opts.Hosts
	conf.LogLevel = opts.LogLevel
	conf.TLS = opts.TLS
	conf.TLSVerify = opts.TLSVerify
	conf.CommonTLSOptions = config.CommonTLSOptions{}

	if opts.TLSOptions != nil {
		conf.CommonTLSOptions.CAFile = opts.TLSOptions.CAFile
		conf.CommonTLSOptions.CertFile = opts.TLSOptions.CertFile
		conf.CommonTLSOptions.KeyFile = opts.TLSOptions.KeyFile
	}

	if conf.TrustKeyPath == "" {
		daemonConfDir, err := getDaemonConfDir(conf.Root)
		if err != nil {
			return nil, err
		}
		conf.TrustKeyPath = filepath.Join(daemonConfDir, defaultTrustKeyFile)
	}

	if flags.Changed("graph") && flags.Changed("data-root") {
		return nil, errors.New(`cannot specify both "--graph" and "--data-root" option`)
	}

	if opts.configFile != "" {
		c, err := config.MergeDaemonConfigurations(conf, flags, opts.configFile)
		if err != nil {
			if flags.Changed("config-file") || !os.IsNotExist(err) {
				return nil, errors.Wrapf(err, "unable to configure the Docker daemon with file %s", opts.configFile)
			}
		}
		// the merged configuration can be nil if the config file didn't exist.
		// leave the current configuration as it is if when that happens.
		if c != nil {
			conf = c
		}
	}

	if err := config.Validate(conf); err != nil {
		return nil, err
	}

	if flags.Changed("graph") {
		logrus.Warnf(`The "-g / --graph" flag is deprecated. Please use "--data-root" instead`)
	}

	// Check if duplicate label-keys with different values are found
	newLabels, err := config.GetConflictFreeLabels(conf.Labels)
	if err != nil {
		return nil, err
	}
	// The namespaces com.docker.*, io.docker.*, org.dockerproject.* have been documented
	// to be reserved for Docker's internal use, but this was never enforced.  Allowing
	// configured labels to use these namespaces are deprecated for 18.05.
	//
	// The following will check the usage of such labels, and report a warning for deprecation.
	//
	// TODO: At the next stable release, the validation should be folded into the other
	// configuration validation functions and an error will be returned instead, and this
	// block should be deleted.
	if err := config.ValidateReservedNamespaceLabels(newLabels); err != nil {
		logrus.Warnf("Configured labels using reserved namespaces is deprecated: %s", err)
	}
	conf.Labels = newLabels

	// Regardless of whether the user sets it to true or false, if they
	// specify TLSVerify at all then we need to turn on TLS
	if conf.IsValueSet(FlagTLSVerify) {
		conf.TLS = true
	}

	return conf, nil
}

func initRouter(opts routerOptions) {
	decoder := runconfig.ContainerDecoder{}

	routers := []router.Router{
		// we need to add the checkpoint router before the container router or the DELETE gets masked
		checkpointrouter.NewRouter(opts.daemon, decoder),
		container.NewRouter(opts.daemon, decoder),
		image.NewRouter(opts.daemon.ImageService()),
		systemrouter.NewRouter(opts.daemon, opts.cluster, opts.buildCache, opts.buildkit, opts.features),
		volume.NewRouter(opts.daemon.VolumesService()),
		build.NewRouter(opts.buildBackend, opts.daemon, opts.features),
		sessionrouter.NewRouter(opts.sessionManager),
		swarmrouter.NewRouter(opts.cluster),
		pluginrouter.NewRouter(opts.daemon.PluginManager()),
		distributionrouter.NewRouter(opts.daemon.ImageService()),
	}

	grpcBackends := []grpcrouter.Backend{}
	for _, b := range []interface{}{opts.daemon, opts.buildBackend} {
		if b, ok := b.(grpcrouter.Backend); ok {
			grpcBackends = append(grpcBackends, b)
		}
	}
	if len(grpcBackends) > 0 {
		routers = append(routers, grpcrouter.NewRouter(grpcBackends...))
	}

	if opts.daemon.NetworkControllerEnabled() {
		routers = append(routers, network.NewRouter(opts.daemon, opts.cluster))
	}

	if opts.daemon.HasExperimental() {
		for _, r := range routers {
			for _, route := range r.Routes() {
				if experimental, ok := route.(router.ExperimentalRoute); ok {
					experimental.Enable()
				}
			}
		}
	}

	opts.api.InitRouter(routers...)
}

// TODO: remove this from cli and return the authzMiddleware
func (cli *DaemonCli) initMiddlewares(s *apiserver.Server, cfg *apiserver.Config, pluginStore plugingetter.PluginGetter) error {
	v := cfg.Version

	exp := middleware.NewExperimentalMiddleware(cli.Config.Experimental)
	s.UseMiddleware(exp)

	vm := middleware.NewVersionMiddleware(v, api.DefaultVersion, api.MinVersion)
	s.UseMiddleware(vm)

	if cfg.CorsHeaders != "" {
		c := middleware.NewCORSMiddleware(cfg.CorsHeaders)
		s.UseMiddleware(c)
	}

	cli.authzMiddleware = authorization.NewMiddleware(cli.Config.AuthorizationPlugins, pluginStore)
	cli.Config.AuthzMiddleware = cli.authzMiddleware
	s.UseMiddleware(cli.authzMiddleware)
	return nil
}

func (cli *DaemonCli) getContainerdDaemonOpts() ([]supervisor.DaemonOpt, error) {
	opts, err := cli.getPlatformContainerdDaemonOpts()
	if err != nil {
		return nil, err
	}

	if cli.Config.Debug {
		opts = append(opts, supervisor.WithLogLevel("debug"))
	} else if cli.Config.LogLevel != "" {
		opts = append(opts, supervisor.WithLogLevel(cli.Config.LogLevel))
	}

	if !cli.Config.CriContainerd {
		opts = append(opts, supervisor.WithPlugin("cri", nil))
	}

	return opts, nil
}

func newAPIServerConfig(cli *DaemonCli) (*apiserver.Config, error) {
	serverConfig := &apiserver.Config{
		Logging:     true,
		SocketGroup: cli.Config.SocketGroup,
		Version:     dockerversion.Version,
		CorsHeaders: cli.Config.CorsHeaders,
	}

	if cli.Config.TLS {
		tlsOptions := tlsconfig.Options{
			CAFile:             cli.Config.CommonTLSOptions.CAFile,
			CertFile:           cli.Config.CommonTLSOptions.CertFile,
			KeyFile:            cli.Config.CommonTLSOptions.KeyFile,
			ExclusiveRootPools: true,
		}

		if cli.Config.TLSVerify {
			// server requires and verifies client's certificate
			tlsOptions.ClientAuth = tls.RequireAndVerifyClientCert
		}
		tlsConfig, err := tlsconfig.Server(tlsOptions)
		if err != nil {
			return nil, err
		}
		serverConfig.TLSConfig = tlsConfig
	}

	if len(cli.Config.Hosts) == 0 {
		cli.Config.Hosts = make([]string, 1)
	}

	return serverConfig, nil
}

func loadListeners(cli *DaemonCli, serverConfig *apiserver.Config) ([]string, error) {
	var hosts []string
	seen := make(map[string]struct{}, len(cli.Config.Hosts))

	for i := 0; i < len(cli.Config.Hosts); i++ {
		var err error
		if cli.Config.Hosts[i], err = dopts.ParseHost(cli.Config.TLS, honorXDG, cli.Config.Hosts[i]); err != nil {
			return nil, errors.Wrapf(err, "error parsing -H %s", cli.Config.Hosts[i])
		}
		if _, ok := seen[cli.Config.Hosts[i]]; ok {
			continue
		}
		seen[cli.Config.Hosts[i]] = struct{}{}

		protoAddr := cli.Config.Hosts[i]
		protoAddrParts := strings.SplitN(protoAddr, "://", 2)
		if len(protoAddrParts) != 2 {
			return nil, fmt.Errorf("bad format %s, expected PROTO://ADDR", protoAddr)
		}

		proto := protoAddrParts[0]
		addr := protoAddrParts[1]

		// It's a bad idea to bind to TCP without tlsverify.
		if proto == "tcp" && (serverConfig.TLSConfig == nil || serverConfig.TLSConfig.ClientAuth != tls.RequireAndVerifyClientCert) {
			logrus.Warn("[!] DON'T BIND ON ANY IP ADDRESS WITHOUT setting --tlsverify IF YOU DON'T KNOW WHAT YOU'RE DOING [!]")
		}
		ls, err := listeners.Init(proto, addr, serverConfig.SocketGroup, serverConfig.TLSConfig)
		if err != nil {
			return nil, err
		}
		ls = wrapListeners(proto, ls)
		// If we're binding to a TCP port, make sure that a container doesn't try to use it.
		if proto == "tcp" {
			if err := allocateDaemonPort(addr); err != nil {
				return nil, err
			}
		}
		logrus.Debugf("Listener created for HTTP on %s (%s)", proto, addr)
		hosts = append(hosts, protoAddrParts[1])
		cli.api.Accept(addr, ls...)
	}

	return hosts, nil
}

func createAndStartCluster(cli *DaemonCli, d *daemon.Daemon) (*cluster.Cluster, error) {
	name, _ := os.Hostname()

	// Use a buffered channel to pass changes from store watch API to daemon
	// A buffer allows store watch API and daemon processing to not wait for each other
	watchStream := make(chan *swarmapi.WatchMessage, 32)

	c, err := cluster.New(cluster.Config{
		Root:                   cli.Config.Root,
		Name:                   name,
		Backend:                d,
		VolumeBackend:          d.VolumesService(),
		ImageBackend:           d.ImageService(),
		PluginBackend:          d.PluginManager(),
		NetworkSubnetsProvider: d,
		DefaultAdvertiseAddr:   cli.Config.SwarmDefaultAdvertiseAddr,
		RaftHeartbeatTick:      cli.Config.SwarmRaftHeartbeatTick,
		RaftElectionTick:       cli.Config.SwarmRaftElectionTick,
		RuntimeRoot:            cli.getSwarmRunRoot(),
		WatchStream:            watchStream,
	})
	if err != nil {
		return nil, err
	}
	d.SetCluster(c)
	err = c.Start()

	return c, err
}

// validates that the plugins requested with the --authorization-plugin flag are valid AuthzDriver
// plugins present on the host and available to the daemon
func validateAuthzPlugins(requestedPlugins []string, pg plugingetter.PluginGetter) error {
	for _, reqPlugin := range requestedPlugins {
		if _, err := pg.Get(reqPlugin, authorization.AuthZApiImplements, plugingetter.Lookup); err != nil {
			return err
		}
	}
	return nil
}

func systemContainerdRunning(honorXDG bool) (string, bool, error) {
	addr := containerddefaults.DefaultAddress
	if honorXDG {
		runtimeDir, err := homedir.GetRuntimeDir()
		if err != nil {
			return "", false, err
		}
		addr = filepath.Join(runtimeDir, "containerd", "containerd.sock")
	}
	_, err := os.Lstat(addr)
	return addr, err == nil, nil
}

// configureDaemonLogs sets the logrus logging level and formatting
func configureDaemonLogs(conf *config.Config) error {
	if conf.LogLevel != "" {
		lvl, err := logrus.ParseLevel(conf.LogLevel)
		if err != nil {
			return fmt.Errorf("unable to parse logging level: %s", conf.LogLevel)
		}
		logrus.SetLevel(lvl)
	} else {
		logrus.SetLevel(logrus.InfoLevel)
	}
	logrus.SetFormatter(&logrus.TextFormatter{
		TimestampFormat: jsonmessage.RFC3339NanoFixed,
		DisableColors:   conf.RawLogs,
		FullTimestamp:   true,
	})
	return nil
}