diff --git a/lib/neutron-legacy b/lib/neutron-legacy
index a3f6f0788d..a5a608df72 100644
--- a/lib/neutron-legacy
+++ b/lib/neutron-legacy
@@ -1039,6 +1039,15 @@ function _ssh_check_neutron {
     test_with_retry "$testcmd" "server $ip didn't become ssh-able" $timeout_sec
 }
 
+function plugin_agent_add_l2_agent_extension {
+    local l2_agent_extension=$1
+    if [[ -z "$L2_AGENT_EXTENSIONS" ]]; then
+        L2_AGENT_EXTENSIONS=$l2_agent_extension
+    elif [[ ! ,${L2_AGENT_EXTENSIONS}, =~ ,${l2_agent_extension}, ]]; then
+        L2_AGENT_EXTENSIONS+=",$l2_agent_extension"
+    fi
+}
+
 # Restore xtrace
 $_XTRACE_NEUTRON
 
diff --git a/lib/neutron_plugins/ml2 b/lib/neutron_plugins/ml2
index e1f868f0a7..f00feac6b4 100644
--- a/lib/neutron_plugins/ml2
+++ b/lib/neutron_plugins/ml2
@@ -156,5 +156,9 @@ function has_neutron_plugin_security_group {
     return 0
 }
 
+function configure_qos_ml2 {
+    neutron_ml2_extension_driver_add "qos"
+}
+
 # Restore xtrace
 $_XTRACE_NEUTRON_ML2
diff --git a/lib/neutron_plugins/services/l3 b/lib/neutron_plugins/services/l3
index 98b96ac06c..72f7a32b26 100644
--- a/lib/neutron_plugins/services/l3
+++ b/lib/neutron_plugins/services/l3
@@ -427,3 +427,12 @@ function is_networking_extension_supported {
     EXT_LIST=$(openstack --os-cloud devstack-admin --os-region "$REGION_NAME" extension list --network -c Alias -f value)
     [[ $EXT_LIST =~ $extension ]] && return 0
 }
+
+function plugin_agent_add_l3_agent_extension {
+    local l3_agent_extension=$1
+    if [[ -z "$L3_AGENT_EXTENSIONS" ]]; then
+        L3_AGENT_EXTENSIONS=$l3_agent_extension
+    elif [[ ! ,${L3_AGENT_EXTENSIONS}, =~ ,${l3_agent_extension}, ]]; then
+        L3_AGENT_EXTENSIONS+=",$l3_agent_extension"
+    fi
+}