Learning HAProxy

HAProxy is an open-source load balancer. HAProxy listens for incomming requests and then forwards them to one of your servers.

HAProxy atcs as both a reverse proxy and a load balancer for TCP-conected applications.

A reverse proxy sits in front of your server and accepts requets from clients on its behalf.

If you have more than one server to redirect TCP connections, then you need a load balancer.

How does it work?

HAProxy uses a single-threaded, event driven architecture to receive requests from clients and dispatch them quickly to backend servers.

It does not open a thread and wait for a server to respond. Instead, it moves on to do other work and returns when it receives a callback.

/usr/sbin/haproxy: it is the binary
/usr/share/lintian/overrides: Lintian is a Debian package checker. The file here overrides rules that would otherwise cause the HAProxy package to be flagged as having an error. (not found).
/usr/share/doc/haproxy: Documentation for HAProxy (It is needed to install the package haproxy-doc).
/run/haproxy: Contains a UNIX socket that HAProxy binds to during startup.
/var/lib/haproxy: Contains data that HAProxy stores while running.
/etc/logrotate.d/haproxy: Configures HAProxy to use logrotate, which manages how logs are compressed and rotated.
/etc/default/haproxy: Contains a default file for HAProxy that can override aspects of how the service starts up.
/etc/haproxy: Contains the HAProxy configuration file and a directory where HTTP error pages are defined.
/etc/init.d/haproxy: Contains the initialization script for the HAProxy service.

/usr/sbin/haproxy -v to get the version of HAProxy

TODO