package daemon
 
 import (

 	"runtime"

 	derr "github.com/docker/docker/errors"

 	"github.com/docker/docker/runconfig"

 	"github.com/docker/docker/utils"

 )
 

 // ContainerStart starts a container.

 func (daemon *Daemon) ContainerStart(name string, hostConfig *runconfig.HostConfig) error {
 	container, err := daemon.Get(name)

 	if err != nil {

 		return err

 	}
 

 	if container.isPaused() {

 		return derr.ErrorCodeStartPaused

 	}
 

 	if container.IsRunning() {

 		return derr.ErrorCodeAlreadyStarted

 	}
 

 	// Windows does not have the backwards compatibility issue here.

 	if runtime.GOOS != "windows" {
 		// This is kept for backward compatibility - hostconfig should be passed when
 		// creating a container, not during start.
 		if hostConfig != nil {

 			if err := daemon.setHostConfig(container, hostConfig); err != nil {

 				return err
 			}
 		}
 	} else {
 		if hostConfig != nil {

 			return derr.ErrorCodeHostConfigStart

 		}
 	}

 	// check if hostConfig is in line with the current system settings.
 	// It may happen cgroups are umounted or the like.

 	if _, err = daemon.verifyContainerSettings(container.hostConfig, nil); err != nil {

 		return err
 	}
 

 	if err := container.Start(); err != nil {

 		return derr.ErrorCodeCantStart.WithArgs(name, utils.GetErrorMessage(err))

 	}

 	return nil

 }