daemon/daemon.go Daemon: containerd libcontainerdtypes.Client
是和containerd交互的client

daemon/start.go
func (daemon *Daemon) containerStart

  1.     err = daemon.containerd.Create(ctx, container.ID, spec, createOptions, withImageName(imageRef.String()))
  2.     if err != nil {
  3.         if errdefs.IsConflict(err) {
  4.             logrus.WithError(err).WithField("container", container.ID).Error("Container not cleaned up from containerd from previous run")
  5.             // best effort to clean up old container object
  6.             daemon.containerd.DeleteTask(ctx, container.ID)
  7.             if err := daemon.containerd.Delete(ctx, container.ID); err != nil && !errdefs.IsNotFound(err) {
  8.                 logrus.WithError(err).WithField("container", container.ID).Error("Error cleaning up stale containerd container object")
  9.             }
  10.             err = daemon.containerd.Create(ctx, container.ID, spec, createOptions, withImageName(imageRef.String()))
  11.         }
  12.         if err != nil {
  13.             return translateContainerdStartErr(container.Path, container.SetExitCode, err)
  14.         }
  15.     }
  17.     // TODO(mlaventure): we need to specify checkpoint options here
  18.     pid, err := daemon.containerd.Start(context.Background(), container.ID, checkpointDir,
  19.         container.StreamConfig.Stdin() != nil || container.Config.Tty,
  20.         container.InitializeStdio)
  21.     if err != nil {
  22.         if err := daemon.containerd.Delete(context.Background(), container.ID); err != nil {
  23.             logrus.WithError(err).WithField("container", container.ID).
  24.                 Error("failed to delete failed start container")
  25.         }
  26.         return translateContainerdStartErr(container.Path, container.SetExitCode, err)
  27.     }

对于docker run这个命令：

实际执行的是 create + start