diff --git a/api/src/com/cloud/api/commands/AssignToLoadBalancerRuleCmd.java b/api/src/com/cloud/api/commands/AssignToLoadBalancerRuleCmd.java
index c68eac39487..f2abb9448f0 100644
--- a/api/src/com/cloud/api/commands/AssignToLoadBalancerRuleCmd.java
+++ b/api/src/com/cloud/api/commands/AssignToLoadBalancerRuleCmd.java
@@ -46,7 +46,7 @@ public class AssignToLoadBalancerRuleCmd extends BaseAsyncCmd {
     @Parameter(name=ApiConstants.ID, type=CommandType.LONG, required=true, description="the ID of the load balancer rule")
     private Long id;
 
-    @Parameter(name=ApiConstants.VIRTUAL_MACHINE_IDS, type=CommandType.LIST, collectionType=CommandType.LONG, required=false, description="the list of IDs of the virtual machine that are being assigned to the load balancer rule(i.e. virtualMachineIds=1,2,3)")
+    @Parameter(name=ApiConstants.VIRTUAL_MACHINE_IDS, type=CommandType.LIST, collectionType=CommandType.LONG, required=true, description="the list of IDs of the virtual machine that are being assigned to the load balancer rule(i.e. virtualMachineIds=1,2,3)")
     private List<Long> virtualMachineIds;
 
     /////////////////////////////////////////////////////