func createContainer(context *cli.Context, id string, spec *specs.Spec) (libcontainer.Container, error) {
    rootless, err := isRootless(context)
    if err != nil {
        return nil, err
    }
    config, err := specconv.CreateLibcontainerConfig(&specconv.CreateOpts{
        CgroupName:       id,
        UseSystemdCgroup: context.GlobalBool("systemd-cgroup"),
        NoPivotRoot:      context.Bool("no-pivot"),
        NoNewKeyring:     context.Bool("no-new-keyring"),
        Spec:             spec,
        Rootless:         rootless,
    })
    if err != nil {
        return nil, err
    }

    factory, err := loadFactory(context)
    if err != nil {
        return nil, err
    }
    return factory.Create(id, config)
}