diff --git a/client/util.go b/client/util.go
index 198bff9654d..15a8babff4d 100644
--- a/client/util.go
+++ b/client/util.go
@@ -14,6 +14,20 @@
 
 package client
 
+import (
+	"regexp"
+)
+
+var (
+	roleNotFoundRegExp *regexp.Regexp
+	userNotFoundRegExp *regexp.Regexp
+)
+
+func init() {
+	roleNotFoundRegExp = regexp.MustCompile("auth: Role .* does not exist.")
+	userNotFoundRegExp = regexp.MustCompile("auth: User .* does not exist.")
+}
+
 // IsKeyNotFound returns true if the error code is ErrorCodeKeyNotFound.
 func IsKeyNotFound(err error) bool {
 	if cErr, ok := err.(Error); ok {
@@ -21,3 +35,19 @@ func IsKeyNotFound(err error) bool {
 	}
 	return false
 }
+
+// IsRoleNotFound returns true if the error means role not found of v2 API.
+func IsRoleNotFound(err error) bool {
+	if ae, ok := err.(authError); ok {
+		return roleNotFoundRegExp.MatchString(ae.Message)
+	}
+	return false
+}
+
+// IsUserNotFound returns true if the error means user not found of v2 API.
+func IsUserNotFound(err error) bool {
+	if ae, ok := err.(authError); ok {
+		return userNotFoundRegExp.MatchString(ae.Message)
+	}
+	return false
+}