一、前言
Haproxy是稳定、高性能、高可用性的负载均衡解决方案，支持HTTP及TCP代理后端服务器池，因支持强大灵活的7层acl规则，广泛作为HTTP反向代理。本文则详细介绍如何利用它的四层交换与Keepalived实现一个负载均衡器，适用于Socket、ICE、Mail、Mysql、私有通讯等任意TCP服务。系统架构图如下：
二、平台环境
OS:Centos5.4(64X)
MASTER:192.168.0.20
BACKUP:192.168.0.21
VIP:192.168.0.100
Serivce Port:11231
三、平台安装配置
1、添加非本机IP邦定支持
#vi /etc/sysctl.conf
net.ipv4.ip_nonlocal_bind=1
#sysctl –p
2、配置平台日志支持
#vi /etc/syslog.conf
添加：
local3.* /var/log/haproxy.log
local0.* /var/log/haproxy.log
#vi /etc/sysconfig/syslog
修改：
SYSLOGD_OPTIONS="-r -m 0"
#/etc/init.d/syslog restart
3、关闭SELINUX
vi /etc/sysconfig/selinux
修改：
SELINUX=disabled
#setenforce 0
4、配置iptables，添加VRRP通讯支持
iptables -A INPUT -d 224.0.0.18 -j ACCEPT
也可以编辑/etc/sysconfig/iptables文件 在倒数第三行添加-A INPUT -d 224.0.0.18 -j ACCEPT
5、Keepalived的安装、配置
#mkdir -p /home/install/keepalivedha
#cd /home/install/keepalivedha
#wget http://www.keepalived.org/software/keepalived-1.2.2.tar.gz
#tar zxvf keepalived-1.2.2.tar.gz
#cd keepalived-1.2.2
#./configure
#make && make install
#cp /usr/local/etc/rc.d/init.d/keepalived /etc/rc.d/init.d/
#cp /usr/local/etc/sysconfig/keepalived /etc/sysconfig/
#mkdir /etc/keepalived
#cp /usr/local/etc/keepalived/keepalived.conf /etc/keepalived/
#cp /usr/local/sbin/keepalived /usr/sbin/
