diff --git a/README.md b/README.md
index 9ec623970..14da37664 100644
--- a/README.md
+++ b/README.md
@@ -49,7 +49,11 @@ user named `daemon` defined within that file-system.
     },
     "process": {
         "terminal": true,
-        "user": "daemon",
+        "user": {
+            "uid": 0,
+            "gid": 0,
+            "additionalGids": null
+        },
         "args": [
             "sh"
         ],
diff --git a/main_unsupported.go b/main_unsupported.go
index 7cb1e9abb..be33a6587 100644
--- a/main_unsupported.go
+++ b/main_unsupported.go
@@ -7,6 +7,10 @@ import (
 	"github.com/codegangsta/cli"
 )
 
+type User struct {
+	NOTSUPPORTED string
+}
+
 func getDefaultID() string {
 	return ""
 }
diff --git a/spec.go b/spec.go
index 42f80c89d..47cf34677 100644
--- a/spec.go
+++ b/spec.go
@@ -9,8 +9,6 @@ import (
 	"github.com/codegangsta/cli"
 )
 
-const cpuQuotaMultiplyer = 100000
-
 type Mount struct {
 	Type        string `json:"type"`
 	Source      string `json:"source"`
@@ -20,7 +18,7 @@ type Mount struct {
 
 type Process struct {
 	Terminal bool     `json:"terminal"`
-	User     string   `json:"user"`
+	User     User     `json:"user"`
 	Args     []string `json:"args"`
 	Env      []string `json:"env"`
 	Cwd      string   `json:"cwd"`
@@ -61,7 +59,7 @@ var specCommand = cli.Command{
 			},
 			Process: Process{
 				Terminal: true,
-				User:     "daemon",
+				User:     User{},
 				Args: []string{
 					"sh",
 				},
diff --git a/spec_linux.go b/spec_linux.go
index 6725e9c40..d49dbdca4 100644
--- a/spec_linux.go
+++ b/spec_linux.go
@@ -30,6 +30,12 @@ type Linux struct {
 	Devices          []string               `json:"devices"`
 }
 
+type User struct {
+	Uid            int32   `json:"uid"`
+	Gid            int32   `json:"gid"`
+	AdditionalGids []int32 `json:"additionalGids"`
+}
+
 type Namespace struct {
 	Type string `json:"type"`
 	Path string `json:"path"`
@@ -273,10 +279,6 @@ func setReadonly(config *configs.Config) {
 	}
 }
 
-func getCPUQuota(cpus float64) int64 {
-	return int64(cpus * cpuQuotaMultiplyer)
-}
-
 func setupUserNamespace(spec *Spec, config *configs.Config) error {
 	if len(spec.Linux.UserMapping) == 0 {
 		return nil
diff --git a/utils.go b/utils.go
index 7153c4d44..8d9f5a67e 100644
--- a/utils.go
+++ b/utils.go
@@ -166,7 +166,7 @@ func newProcess(p Process) *libcontainer.Process {
 	return &libcontainer.Process{
 		Args:   p.Args,
 		Env:    p.Env,
-		User:   p.User,
+		User:   fmt.Sprintf("%d:%d", p.User.Uid, p.User.Gid),
 		Cwd:    p.Cwd,
 		Stdin:  os.Stdin,
 		Stdout: os.Stdout,