The role of the load balancer is to distribute client requests across the pool of servers including rerouting requests when a member of the pool fails. LBaaS leverages agents that control the HAProxy configuration and manage the HAProxy daemon. These HAProxy based load balancers have network access to clients and to the member servers which answer client requests by requesting and receiving Neutron networks ports and IP Addresses.
This service lets you configure a load balancer that runs outside of your instances and directs traffic to your instances. A common use case occurs when you want to use multiple instances to serve web pages and you also want to meet high performance or availability goals.
By leveraging load balancers, client requests can be serviced in such a way as to mitigate against bottlenecks due to resource contention on any given server or against failed requests due to failures on any given servers.
LBaaS allows workload control
LBaaS assists with mitigating DoS (Denial of Service) attacks
LBaaS ensures that incoming requests are routed to the same instance within a pool of multiple instances
LBaaS provides load balancers on demand and in the case of metered clouds
You pay for load balancing services on a utility basis