code: func newServeCmd(stdin io.Reader, stdout, stderr io.Writer) *cobra.Command {
  	Server = server.NewCommand(stdin, stdout, stderr)
  	serveCmd := &cobra.Command{
  		Use:   "server",
  		Short: "Run Pilosa.",
  		Long: `pilosa server runs Pilosa.
  
  It will load existing data from the configured
  directory and start listening for client connections
  on the configured port.`,
  		RunE: func(cmd *cobra.Command, args []string) error {
  			// Start & run the server.
  			if err := Server.Start(); err != nil {
  				return errors.Wrap(err, "running server")
  			}
  
  			// Initialize tracing in the command since it is global.
  			var cfg jaegercfg.Configuration
  			cfg.ServiceName = "pilosa"
  			cfg.Sampler = &jaegercfg.SamplerConfig{
  				Type:  Server.Config.Tracing.SamplerType,
  				Param: Server.Config.Tracing.SamplerParam,
  			}
  			cfg.Reporter = &jaegercfg.ReporterConfig{
  				LocalAgentHostPort: Server.Config.Tracing.AgentHostPort,
  			}
  			tracer, closer, err := cfg.NewTracer()
  			if err != nil {
  				return errors.Wrap(err, "initializing jaeger tracer")
  			}
  			defer closer.Close()
  			tracing.GlobalTracer = opentracing.NewTracer(tracer)
  
  			return errors.Wrap(Server.Wait(), "waiting on Server")
  		},
  	}
  
  	// Attach flags to the command.
  	ctl.BuildServerFlags(serveCmd, Server)
  	return serveCmd
  }
docs: // newServeCmd creates a pilosa server and runs it with command line flags.