VRRP is a neat way to make your setup redundant the right way and balance over an IP from one machine to another. I have touched on IPVS last week in a simple setup, here is now another way to do a neater more robust setup. If you recall last week’s example, we had a reachable IP of 192.168.66.6 which we routed http traffic on. For this to work you also need a static IP within the same subnet like 192.168.66.5. Once configured you can check your setup with ip addr (sadly ifconfig is too broken to show the second IP to you as I discovered lately…).

Here is the keepalived.conf file:

global_defs {
        router_id  My_LB_1
}
vrrp_instance lb_network {
        state BACKUP
        interface eth0
        track_interface {
                eth0
        }
	lvs_sync_daemon_interface eth0
        virtual_router_id 100
        priority 150
        authentication {
                auth_type PASS
                auth_pass superfancysecretpass
        }
        virtual_ipaddress {
                192.168.66.6
        }
        nopreempt
}
virtual_server 192.168.66.6 80 {
        delay_loop 30
        lb_algo wrr
        lb_kind NAT
        protocol TCP

        real_server 10.10.1.101 80 {
                weight 10
                TCP_CHECK {
                        connect_timeout 3
                }
        }
        real_server 10.10.1.102 80 {
                weight 10
                TCP_CHECK {
                        connect_timeout 3
                }
        }
}

And this is the config for the second box:

global_defs {
        router_id  My_LB_2
}

vrrp_instance lb_network {
        state BACKUP
        interface eth0
        track_interface {
                eth0
        }
	lvs_sync_daemon_interface eth0
        virtual_router_id 100
        priority 100
        authentication {
                auth_type PASS
                auth_pass superfancysecretpass
        }
        virtual_ipaddress {
                192.168.66.6
        }
        nopreempt
}
virtual_server 192.168.66.6 80 {
        delay_loop 30
        lb_algo wrr
        lb_kind NAT
        protocol TCP

        real_server 10.10.1.101 80 {
                weight 10
                TCP_CHECK {
                        connect_timeout 3
                }
        }
        real_server 10.10.1.102 80 {
                weight 10
                TCP_CHECK {
                        connect_timeout 3
                }
        }
}

There you are, redundant setup with keepalived 🙂