简介

HAProxy is a free,veryfast and reliable solution offeringhigh availability,load balancing, and proxying for TCP and HTTP-based applications. It is particularly suited for very high traffic web sites and powers quite a number of the world's most visited ones. Over the years it has become the de-facto standard opensource load balancer, is now shipped with most mainstream Linux distributions, and is often deployed by default in cloud platforms. Since it does not advertise itself, we only know it's used when theadmins report it:-)

Its mode of operation makes its integration into existing architectures very easy and riskless, while still offering the possibility not to expose fragile web servers to the net, such as below :

We always support at least two active versions in parallel and an extra old one in critical fixes mode only. The currently supported versions are :

• version 1.7 : added server hot reconfiguration, content processing agents, multi-type certs, ...
• version 1.6 : added DNS resolution support, HTTP connection multiplexing, full stick-table replication, stateless compression, ...
• version 1.5 : added SSL, IPv6, keep-alive, DDoS protection, ...
• version 1.4 : the most stable version for people who don't need SSL. Still provides client-side keep-alive
• version 1.3 : the old stable version for companies who cannot upgrade for internal policy reasons.