HAProxy提供高可用性、负载均衡以及基于TCP和HTTP应用的代理，支持虚拟主机，它是免费、快速并且可靠的一种解决方案。HAProxy特别适用于那些负载特大的web站点，这些站点通常又需要会话保持或七层处理。HAProxy运行在当前的硬件上，完全可以支持数以万计的并发连接。并且它的运行模式使得它可以很简单安全的整合进您当前的架构中，同时可以保护你的web服务器不被暴露到网络上。
很好用的4,7层负载均衡软件Haproxy 1.4.25发布。2014-03-28 上一个版本还是2013-06-17的1.4.24.修正了一些Bug以及功能增强。下一个产品系列1.5也已发布Dev22。
完全改进：
2014/03/27 : 1.4.25
- DOC: typo: nosepoll self reference in config guide
- BUG/MINOR: deinit: free fdinfo while doing cleanup
- BUG/MEDIUM: server: set the macro for server's max weight SRV_UWGHT_MAX to SRV_UWGHT_RANGE
- BUG/MINOR: use the same check condition for server as other algorithms
- BUG/MINOR: stream-int: also consider ENOTCONN in addition to EAGAIN for recv()
- BUG/MINOR: fix forcing fastinter in "on-error"
- BUG/MEDIUM: http/auth: Sometimes the authentication credentials can be mix between two requests
- BUG/MAJOR: http: don't emit the send-name-header when no server is available
- BUG/MEDIUM: http: "option checkcache" fails with the no-cache header
- MEDIUM: session: disable lingering on the server when the client aborts
- MINOR: config: warn when a server with no specific port uses rdp-cookie
- MEDIUM: increase chunk-size limit to 2GB-1
- DOC: add a mention about the limited chunk size
- MEDIUM: http: add "redirect scheme" to ease HTTP to HTTPS redirection
- BUILD: proto_tcp: remove a harmless warning
- BUG/MINOR: acl: remove patterns from the tree before freeing them
- BUG/MEDIUM: checks: fix slow start regression after fix attempt
- BUG/MAJOR: server: weight calculation fails for map-based algorithms
- BUG/MINOR: backend: fix target address retrieval in transparent mode
- BUG/MEDIUM: stick: completely remove the unused flag from the store entries
- BUG/MEDIUM: stick-tables: complete the latest fix about store-responses
- BUG/MEDIUM: checks: tracking servers must not inherit the MAINT flag
- BUG/MINOR: stats: report correct throttling percentage for servers in slowstart
- BUG/MINOR: stats: correctly report throttle rate of low weight servers
- BUG/MINOR: checks: successful check completion must not re-enable MAINT servers
- BUG/MEDIUM: stats: the web interface must check the tracked servers before enabling
- BUG/MINOR: channel: initialize xfer_small/xfer_large on new buffers
- BUG/MINOR: stream-int: also consider ENOTCONN in addition to EAGAIN
- BUG/MEDIUM: http: don't start to forward request data before the connect
- DOC: fix misleading information about SIGQUIT
- BUILD: simplify the date and version retrieval in the makefile
- BUILD: prepare the makefile to skip format lines in SUBVERS and VERDATE
- BUILD: use format tags in VERDATE and SUBVERS files
下载：http://haproxy.1wt.eu/download/1.4/src/haproxy-1.4.25.tar.gz
来自:开源中国社区
