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.
Note that LVS still must be configured when adding a Node. This feature is built on top of the existing cluster feature.
The virtual hosts on the cluster nodes will now listen to the ip address on the main network interface.
This will update existing virtual hosts on the cluster nodes to now listen on the primary network interface IP address rather than the loopback or tunnel device normally used for LVS-DR or LVS-TUN.
At this point, you will now configure the external load balancer. External load balancers tested with this setting include HAProxy, AWS Elastic Load Balancing, and Google Cloud Load Balancing. Configuring these services are outside the scope of this guide.