diff --git a/exercises/floating_ips.sh b/exercises/floating_ips.sh
index 4d71d49..7055278 100755
--- a/exercises/floating_ips.sh
+++ b/exercises/floating_ips.sh
@@ -127,7 +127,7 @@
 # Boot instance
 # -------------
 
-VM_UUID=$(nova boot --flavor $INSTANCE_TYPE --image $IMAGE --security_groups=$SECGROUP $VM_NAME | grep ' id ' | get_field 2)
+VM_UUID=$(nova boot --flavor $INSTANCE_TYPE --image $IMAGE --security-groups=$SECGROUP $VM_NAME | grep ' id ' | get_field 2)
 die_if_not_set $LINENO VM_UUID "Failure launching $VM_NAME"
 
 # Check that the status is active within ACTIVE_TIMEOUT seconds