How to OpenContrail neutron enable LBaaS:Load Balancing as a Service extension

1)
How to install OpenStack with Neutron and contrail-neutron-plugin using DevStack
http://fosshelp.blogspot.com/2015/04/how-to-install-openstack-with-neutron.html

2)
Enable LBaaS:Load Balancing as a Service extension

a)
Specify OpenContrail Loadbalancer service Plugin in /ect/neutron/neutron.conf

b)
Specify 'Opencontrail' LBaaS service provider in /ect/neutron/neutron.conf and comment out all other LBaaS providers and restart neutron server

#vim /ect/neutron/neutron.conf

[DEFAULT]
service_plugins = neutron_plugin_contrail.plugins.opencontrail.loadbalancer.plugin.LoadBalancerPlugin

[service_providers]
#'Opencontrail' LBaaS provider
service_provider = LOADBALANCER:Opencontrail:neutron_plugin_contrail.plugins.opencontrail.loadbalancer.driver.OpencontrailLoadbalancerDriver:default

3)
Check whether extension is loaded or not
#neutron ext-list
+-----------------------+-------------------------------+
| alias                 | name                          |
+-----------------------+-------------------------------+
| contrail              | Contrail Extension            |
| port-security         | Port Security                 |
| security-group        | security-group                |
| ipam                  | Network IP Address Management |
| external-net          | Neutron external network      |
| binding               | Port Binding                  |
| quotas                | Quota management support      |
| agent                 | agent                         |
| route-table           | route-table                   |
| policy                | Network Policy                |
| router                | Neutron L3 Router             |
| allowed-address-pairs | Allowed Address Pairs         |
| extra_dhcp_opt        | Neutron Extra DHCP opts       |
| lbaas                 | LoadBalancing service         |
+-----------------------+-------------------------------+