Learning CoreOS

HAProxy and service discovery

In this section, we use service discovery to create a web service that has multiple backend nodes with HAProxy frontend and then load balancing the service requests. HAProxy is a commonly used load balancer for TCP and HTTP-based applications.

Let's start by understanding a typical HAProxy configuration. We are not going to cover the HAProxy configuration exhaustively, but will only concentrate on the configurations that are relevant for service discovery:

frontend testloadbalancer
    bind *:80
    mode http
    balance roundrobin
    server testserver01 172.17.18.101:80 check
    server testserver02 172.17.18.102:80 check

This configuration instructs HAProxy to bind to port 80 and forward HTTP traffic to the servers 172.17.18.10 ...