How to: Enable External Load Balancer Mode
==========================================

The External Load Balancer Mode is intended to work with networking environments where LVS load balancing is not supported,
or an external load balancer is preferred.

LVS load balancing relies on "IP spoofing" to allow the nodes to respond, directly, to requests as if it were the 
Cluster Manager. In some network configurations, these responses are blocked. With External Load Balancer Mode enabled, 
the virtual hosts on the cluster Nodes listen to the primary network interface IP address, rather than the loopback or 
tunnel device normally used for LVS-DR or LVS-TUN.

External load balancers tested with this setting include `HAProxy
<http://haproxy.org>`__, `AWS Elastic Load Balancing,
<https://aws.amazon.com/elasticloadbalancing/>`__ and \ `Google Cloud Load
Balancing <https://cloud.google.com/load-balancing/>`__. Configuring these services are outside the scope of this guide.

.. note::

   A fully configured Cluster Manager must be set up, with at least one Node added, in order to enable External Load 
   Balancing. LVS must be configured when adding the Node. Instructions on designating an InterWorx server to act as the 
   Cluster Manager can be found :doc:`here</clustering/set-interworx-control-panel-cluster-manager>`.
   Instructions on adding a Node can be found :doc:`here</clustering/set-new-node-interworx-control-panel-cluster>`. 
   

.. contents::

To Enable External Load Balancing
---------------------------------

#. On the Cluster Manager, log into NodeWorx from the browser (https://ip.ad.dr.ess:2443/nodeworx)
#. In NodeWorx, navigate to **Clustering > Load Balancing** 
#. At the top of the page, under External Load Balancer Configuration, select **On** from the External LB Mode options

   .. image:: /images/clustering-external-lb-configuration.png
      :alt: external load balancer options

#. Click **Save**