diff --git a/metropolis/cli/metroctl/main.go b/metropolis/cli/metroctl/main.go
index 29d44e8..d575c5b 100644
--- a/metropolis/cli/metroctl/main.go
+++ b/metropolis/cli/metroctl/main.go
@@ -10,6 +10,18 @@
 	Short: "metroctl controls Metropolis nodes and clusters.",
 }
 
+type metroctlFlags struct {
+	// clusterEndpoints is a list of the targeted cluster's endpoints, used by
+	// commands that perform RPC on it.
+	clusterEndpoints []string
+}
+
+var flags metroctlFlags
+
+func init() {
+	rootCmd.PersistentFlags().StringArrayVar(&flags.clusterEndpoints, "endpoints", nil, "A list of the target cluster's endpoints.")
+}
+
 func main() {
 	cobra.CheckErr(rootCmd.Execute())
 }