diff --git a/manage.go b/manage.go
index 86cd9c4341..2c6fd39f05 100644
--- a/manage.go
+++ b/manage.go
@@ -81,7 +81,7 @@ func manage(c *cli.Context) {
 	cluster := cluster.NewCluster(store, tlsConfig, c.Float64("overcommit"))
 	cluster.Events(&logHandler{})
 
-	if !c.IsSet("discovery") {
+	if c.String("discovery") == "" {
 		log.Fatal("--discovery required to manage a cluster")
 	}