Linux Admin Zone

After configuration of HAProxy to balance web traffic, I’ve noticed that HAProxy is not generating any logs in my server. Due to its load balancer role, logging is vital to diagnose any issue that might come in future.

In its default config, HAProxy send logs to a syslog facility: local0, via a socket connection. By default, your syslog configuration probably doesn’t accept socket connections, and even doesn’t have a local0 facility, so you have no HAProxy log. If you want it, configure syslog to accept TCP connections by adding -r to syslogd parameters.

Sometimes we have different servers with different contents, such as one set of servers with all static contents (html, image files) of a website while another set of servers have dynamic contents (cgi, perl, php scripts) This type of config is benefitial in some situations where you want to serve your static data directly from CDN for faster response and dynamic contents from your own servers.

While deploying a load balancer, we need some mechanisam to inform loadbalancer to forward request to different set of servers based on the condition specified. Here I’m using HAProxy load balancer on CentOS 5 box. This is a very small test setup in Amazon EC2 environment having 3 small instances.