Load Balancer as a Service (LBaaS)

Load Balancer as a Service (LBaaS)

The Networking service offers a load balancer feature called “LBaaS v2” through the neutron-lbaas service plug-in.

LBaaS v2 adds the concept of listeners to the LBaaS v1 load balancers. LBaaS v2 allows you to configure multiple listener ports on a single load balancer IP address.

There are two reference implementations of LBaaS v2. The one is an agent based implementation with HAProxy. The agents handle the HAProxy configuration and manage the HAProxy daemon. Another LBaaS v2 implementation, Octavia, has a separate API and separate worker processes that build load balancers within virtual machines on hypervisors that are managed by the Compute service. You do not need an agent for Octavia.


Currently, no migration path exists between v1 and v2 load balancers. If you choose to switch from v1 to v2, you must recreate all load balancers, pools, and health monitors.

LBaaS v2 Concepts

LBaaS v2 has several new concepts to understand:

LBaaS v2 layout
Load balancer
The load balancer occupies a neutron network port and has an IP address assigned from a subnet.
Load balancers can listen for requests on multiple ports. Each one of those ports is specified by a listener.
A pool holds a list of members that serve content through the load balancer.
Members are servers that serve traffic behind a load balancer. Each member is specified by the IP address and port that it uses to serve traffic.
Health monitor
Members may go offline from time to time and health monitors divert traffic away from members that are not responding properly. Health monitors are associated with pools.

LBaaS v2 has multiple implementations via different service plug-ins. The two most common implementations use either an agent or the Octavia services. Both implementations use the LBaaS v2 API.


Configuring LBaaS v2 with an agent

  1. Add the LBaaS v2 service plug-in to the service_plugins configuration directive in /etc/neutron/neutron.conf. The plug-in list is comma-separated:

    service_plugins = [existing service plugins],neutron_lbaas.services.loadbalancer.plugin.LoadBalancerPluginv2
  2. Add the LBaaS v2 service provider to the service_provider configuration directive within the [service_providers] section in /etc/neutron/neutron_lbaas.conf:

    service_provider = LOADBALANCERV2:Haproxy:neutron_lbaas.drivers.haproxy.plugin_driver.HaproxyOnHostPluginDriver:default

    If you have existing service providers for other networking service plug-ins, such as VPNaaS or FWaaS, add the service_provider line shown above in the [service_providers] section as a separate line. These configuration directives are repeatable and are not comma-separated.

  3. Select the driver that manages virtual interfaces in /etc/neutron/lbaas_agent.ini:

    device_driver = neutron_lbaas.drivers.haproxy.namespace_driver.HaproxyNSDriver
    interface_driver = INTERFACE_DRIVER
    user_group = haproxy

    Replace INTERFACE_DRIVER with the interface driver that the layer-2 agent in your environment uses. For example, openvswitch for Open vSwitch or linuxbridge for Linux bridge.

  4. Run the neutron-lbaas database migration:

    neutron-db-manage --subproject neutron-lbaas upgrade head
  5. If you have deployed LBaaS v1, stop the LBaaS v1 agent now. The v1 and v2 agents cannot run simultaneously.

  6. Start the LBaaS v2 agent:

    neutron-lbaasv2-agent \
    --config-file /etc/neutron/neutron.conf \
    --config-file /etc/neutron/lbaas_agent.ini
  7. Restart the Network service to activate the new configuration. You are now ready to create load balancers with the LBaaS v2 agent.

Configuring LBaaS v2 with Octavia

Octavia provides additional capabilities for load balancers, including using a compute driver to build instances that operate as load balancers. The Hands on Lab - Install and Configure OpenStack Octavia session at the OpenStack Summit in Tokyo provides an overview of Octavia.

The DevStack documentation offers a simple method to deploy Octavia and test the service with redundant load balancer instances. If you already have Octavia installed and configured within your environment, you can configure the Network service to use Octavia:

  1. Add the LBaaS v2 service plug-in to the service_plugins configuration directive in /etc/neutron/neutron.conf. The plug-in list is comma-separated:

    service_plugins = [existing service plugins],neutron_lbaas.services.loadbalancer.plugin.LoadBalancerPluginv2
  2. Add the Octavia service provider to the service_provider configuration directive within the [service_providers] section in /etc/neutron/neutron_lbaas.conf:

    service_provider = LOADBALANCERV2:Octavia:neutron_lbaas.drivers.octavia.driver.OctaviaDriver:default

    Ensure that the LBaaS v1 and v2 service providers are removed from the [service_providers] section. They are not used with Octavia. Verify that all LBaaS agents are stopped.

  3. Restart the Network service to activate the new configuration. You are now ready to create and manage load balancers with Octavia.

Add LBaaS panels to Dashboard

The Dashboard panels for managing LBaaS v2 are available starting with the Mitaka release.

  1. Clone the neutron-lbaas-dashboard repository and check out the release branch that matches the installed version of Dashboard:

    $ git clone https://git.openstack.org/openstack/neutron-lbaas-dashboard
    $ cd neutron-lbaas-dashboard
    $ git checkout OPENSTACK_RELEASE
  2. Install the Dashboard panel plug-in:

    $ python setup.py install
  3. Copy the _1481_project_ng_loadbalancersv2_panel.py file from the neutron-lbaas-dashboard/enabled directory into the Dashboard openstack_dashboard/local/enabled directory.

    This step ensures that Dashboard can find the plug-in when it enumerates all of its available panels.

  4. Enable the plug-in in Dashboard by editing the local_settings.py file and setting enable_lb to True in the OPENSTACK_NEUTRON_NETWORK dictionary.

  5. If Dashboard is configured to compress static files for better performance (usually set through COMPRESS_OFFLINE in local_settings.py), optimize the static files again:

    $ ./manage.py collectstatic
    $ ./manage.py compress
  6. Restart Apache to activate the new panel:

    $ sudo service apache2 restart

To find the panel, click on Project in Dashboard, then click the Network drop-down menu and select Load Balancers.

LBaaS v2 operations

The same neutron commands are used for LBaaS v2 with an agent or with Octavia.

Building an LBaaS v2 load balancer

  1. Start by creating a load balancer on a network. In this example, the private network is an isolated network with two web server instances:

    $ neutron lbaas-loadbalancer-create --name test-lb private-subnet
  2. You can view the load balancer status and IP address with the neutron lbaas-loadbalancer-show command:

    $ neutron lbaas-loadbalancer-show test-lb
    | Field               | Value                                          |
    | admin_state_up      | True                                           |
    | description         |                                                |
    | id                  | 7780f9dd-e5dd-43a9-af81-0d2d1bd9c386           |
    | listeners           | {"id": "23442d6a-4d82-40ee-8d08-243750dbc191"} |
    |                     | {"id": "7e0d084d-6d67-47e6-9f77-0115e6cf9ba8"} |
    | name                | test-lb                                        |
    | operating_status    | ONLINE                                         |
    | provider            | octavia                                        |
    | provisioning_status | ACTIVE                                         |
    | tenant_id           | fbfce4cb346c4f9097a977c54904cafd               |
    | vip_address         |                                     |
    | vip_port_id         | 9f8f8a75-a731-4a34-b622-864907e1d556           |
    | vip_subnet_id       | f1e7827d-1bfe-40b6-b8f0-2d9fd946f59b           |
  3. Update the security group to allow traffic to reach the new load balancer. Create a new security group along with ingress rules to allow traffic into the new load balancer. The neutron port for the load balancer is shown as vip_port_id above.

    Create a security group and rules to allow TCP port 80, TCP port 443, and all ICMP traffic:

    $ neutron security-group-create lbaas
    $ neutron security-group-rule-create \
      --direction ingress \
      --protocol tcp \
      --port-range-min 80 \
      --port-range-max 80 \
      --remote-ip-prefix \
    $ neutron security-group-rule-create \
      --direction ingress \
      --protocol tcp \
      --port-range-min 443 \
      --port-range-max 443 \
      --remote-ip-prefix \
    $ neutron security-group-rule-create \
      --direction ingress \
      --protocol icmp \

    Apply the security group to the load balancer’s network port using vip_port_id from the neutron lbaas-loadbalancer-show command:

    $ neutron port-update \
      --security-group lbaas \

Adding an HTTP listener

  1. With the load balancer online, you can add a listener for plaintext HTTP traffic on port 80:

    $ neutron lbaas-listener-create \
      --name test-lb-http \
      --loadbalancer test-lb \
      --protocol HTTP \
      --protocol-port 80

    This load balancer is active and ready to serve traffic on

  2. Verify that the load balancer is responding to pings before moving further:

    $ ping -c 4
    PING ( 56(84) bytes of data.
    64 bytes from icmp_seq=1 ttl=62 time=0.410 ms
    64 bytes from icmp_seq=2 ttl=62 time=0.407 ms
    64 bytes from icmp_seq=3 ttl=62 time=0.396 ms
    64 bytes from icmp_seq=4 ttl=62 time=0.397 ms
    --- ping statistics ---
    4 packets transmitted, 4 received, 0% packet loss, time 2997ms
    rtt min/avg/max/mdev = 0.396/0.402/0.410/0.020 ms
  3. You can begin building a pool and adding members to the pool to serve HTTP content on port 80. For this example, the web servers are and

    $ neutron lbaas-pool-create \
      --name test-lb-pool-http \
      --lb-algorithm ROUND_ROBIN \
      --listener test-lb-http \
      --protocol HTTP
    $ neutron lbaas-member-create \
      --name test-lb-http-member-1 \
      --subnet private-subnet \
      --address \
      --protocol-port 80 \
    $ neutron lbaas-member-create \
      --name test-lb-http-member-2 \
      --subnet private-subnet \
      --address \
      --protocol-port 80 \
  4. You can use curl to verify connectivity through the load balancers to your web servers:

    $ curl
    $ curl
    $ curl
    $ curl

    In this example, the load balancer uses the round robin algorithm and the traffic alternates between the web servers on the backend.

  5. You can add a health monitor so that unresponsive servers are removed from the pool:

    $ neutron lbaas-healthmonitor-create \
      --name test-lb-http-monitor \
      --delay 5 \
      --max-retries 2 \
      --timeout 10 \
      --type HTTP \
      --pool test-lb-pool-http

    In this example, the health monitor removes the server from the pool if it fails a health check at two five-second intervals. When the server recovers and begins responding to health checks again, it is added to the pool once again.

Adding an HTTPS listener

You can add another listener on port 443 for HTTPS traffic. LBaaS v2 offers SSL/TLS termination at the load balancer, but this example takes a simpler approach and allows encrypted connections to terminate at each member server.

  1. Start by creating a listener, attaching a pool, and then adding members:

    $ neutron lbaas-listener-create \
      --name test-lb-https \
      --loadbalancer test-lb \
      --protocol HTTPS \
      --protocol-port 443
    $ neutron lbaas-pool-create \
      --name test-lb-pool-https \
      --lb-algorithm LEAST_CONNECTIONS \
      --listener test-lb-https \
      --protocol HTTPS
    $ neutron lbaas-member-create \
      --name test-lb-https-member-1 \
      --subnet private-subnet \
      --address \
      --protocol-port 443 \
    $ neutron lbaas-member-create \
      --name test-lb-https-member-2 \
      --subnet private-subnet \
      --address \
      --protocol-port 443 \
  2. You can also add a health monitor for the HTTPS pool:

    $ neutron lbaas-healthmonitor-create \
      --name test-lb-https-monitor \
      --delay 5 \
      --max-retries 2 \
      --timeout 10 \
      --type HTTPS \
      --pool test-lb-pool-https

    The load balancer now handles traffic on ports 80 and 443.

Associating a floating IP address

Load balancers that are deployed on a public or provider network that are accessible to external clients do not need a floating IP address assigned. External clients can directly access the virtual IP address (VIP) of those load balancers.

However, load balancers deployed onto private or isolated networks need a floating IP address assigned if they must be accessible to external clients. To complete this step, you must have a router between the private and public networks and an available floating IP address.

You can use the neutron lbaas-loadbalancer-show command from the beginning of this section to locate the vip_port_id. The vip_port_id is the ID of the network port that is assigned to the load balancer. You can associate a free floating IP address to the load balancer using neutron floatingip-associate:

$ neutron floatingip-associate FLOATINGIP_ID LOAD_BALANCER_PORT_ID

Setting quotas for LBaaS v2

Quotas are available for limiting the number of load balancers and load balancer pools. By default, both quotas are set to 10.

You can adjust quotas using the neutron quota-update command:

$ neutron quota-update --tenant-id TENANT_UUID --loadbalancer 25
$ neutron quota-update --tenant-id TENANT_UUID --pool 50

A setting of -1 disables the quota for a tenant.

Retrieving load balancer statistics

The LBaaS v2 agent collects four types of statistics for each load balancer every six seconds. Users can query these statistics with the neutron lbaas-loadbalancer-stats command:

$ neutron lbaas-loadbalancer-stats test-lb
| Field              | Value    |
| active_connections | 0        |
| bytes_in           | 40264557 |
| bytes_out          | 71701666 |
| total_connections  | 384601   |

The active_connections count is the total number of connections that were active at the time the agent polled the load balancer. The other three statistics are cumulative since the load balancer was last started. For example, if the load balancer restarts due to a system error or a configuration change, these statistics will be reset.

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