Design tested in v1.23 and v1.25.

Author: Jing Zhang

pkg/openstack/instances.go

@@ -640,7 +640,7 @@ func nodeAddresses(srv *servers.Server, ports []ports.Port, client *gophercloud.
 	if client != nil {
 		subports, err := getSubports(client, srv.ID)
 		if err == nil {
-			var subportAddresses map[string][]Address
+			subportAddresses := make(map[string][]Address)
 			for _, subport := range subports {
 				for _, fixedIP := range subport.FixedIPs {
 					isIPv6 := net.ParseIP(fixedIP.IPAddress).To4() == nil