@@ -72,7 +72,7 @@ func (daemon *Daemon) createSpec(c *container.Container) (*libcontainerd.Spec, e

 	s.Process.Env = c.CreateDaemonEnvironment(linkedEnv)

 	s.Process.InitialConsoleSize = c.HostConfig.ConsoleSize

 	s.Process.Terminal = c.Config.Tty

-	s.Process.User.User = c.Config.User

+	s.Process.User.Username = c.Config.User

 	// In spec.Root

 	s.Root.Path = c.BaseFS

@@ -66,9 +66,16 @@ type Process struct {

 	Cwd string `json:"cwd"`

 }

-// User contains the user information for Windows

+// User specifies specific user (and group) information for the container process.

 type User struct {

-	User string `json:"user,omitempty"`

+	// UID is the user id.

+	UID uint32 `json:"uid" platform:"linux,solaris"`

+	// GID is the group id.

+	GID uint32 `json:"gid" platform:"linux,solaris"`

+	// AdditionalGids are additional group ids set for the container's process.

+	AdditionalGids []uint32 `json:"additionalGids,omitempty" platform:"linux,solaris"`

+	// Username is the user name.

+	Username string `json:"username,omitempty" platform:"windows"`

 }

 // Root contains information about the container's root filesystem on the host.