默认情况下keepalived启动时会去/etc/keepalived目录下找配置文件，将需要的配置文件拷贝到指定位置
　　# cp /usr/local/keepalived/etc/rc.d/init.d/keepalived /etc/rc.d/init.d/
　　# cp /usr/local/keepalived/etc/sysconfig/keepalived /etc/sysconfig/
　　# cp /usr/local/keepalived/etc/keepalived/keepalived.conf /etc/keepalived/
　　# cp /usr/local/keepalived/sbin/keepalived /usr/sbin/
　　# chkconfig mysqld on
　　# chkconfig keepalived on
　　LVS安装
　　ipvsadm下载地址
　　需要安装以下软件包
　　# yum install -y libnl* popt*
　　查看是否加载lvs模块
　　# modprobe -l |grep ipvs
　　解压安装
　　# ln -s /usr/src/kernels/2.6.32-431.5.1.el6.x86_64/ /usr/src/linux
　　# tar -zxvf ipvsadm-1.26.tar.gz
　　# make
　　LVS安装完成，查看当前LVS集群
　　# ipvsadm -L -n
　　IP Virtual Server version 1.2.1 (size=4096)
　　Prot LocalAddress:Port Scheduler Flags
　　-> RemoteAddress:Port           Forward Weight ActiveConn InActConn
　　LVS+Keepalived配置
　　搭建MySQL主主复制
　　这里不再赘述，请参考MySQL复制
　　配置Keepalived
　　下面是LVS1节点（Keepalived主节点）上的Keepalived配置，LVS2类似
# vim /etc/keepalived/keepalived.conf
! Configuration File for keepalived
global_defs {
router_id LVS1
}
vrrp_instance VI_1 {
state MASTER #指定instance初始状态，实际根据优先级决定.backup节点不一样
interface eth0 #虚拟IP所在网
virtual_router_id 51 #VRID，相同VRID为一个组，决定多播MAC地址
priority 100 #优先级，另一台改为90.backup节点不一样
advert_int 1  #检查间隔
authentication {
auth_type PASS  #认证方式，可以是pass或ha
auth_pass 1111  #认证密码
}
virtual_ipaddress {
192.168.1.100  #VIP
}
}
virtual_server 192.168.1.100 3306 {
delay_loop 6  #服务轮询的时间间隔
lb_algo wrr  #加权轮询调度，LVS调度算法 rr|wrr|lc|wlc|lblc|sh|sh
lb_kind DR   #LVS集群模式 NAT|DR|TUN，其中DR模式要求负载均衡器网卡必须有一块与物理网卡在同一个网段
#nat_mask 255.255.255.0
persistence_timeout 50  #会话保持时间
protocol TCP  #健康检查协议
## Real Server设置，3306是MySQL连接端口
real_server 192.168.1.5 3306 {
weight 3  ##权重
TCP_CHECK {
connect_timeout 3
nb_get_retry 3
delay_before_retry 3
connect_port 3306
}
}
real_server 192.168.1.6 3306 {
weight 3
TCP_CHECK {
connect_timeout 3
nb_get_retry 3
delay_before_retry 3
connect_port 3306
}
}
}
　　配置LVS
　　编写LVS启动脚本/etc/init.d/realserver
#!/bin/sh
VIP=192.168.1.100
. /etc/rc.d/init.d/functions
case "$1" in
# 禁用本地的ARP请求、绑定本地回环地址
start)
/sbin/ifconfig lo down
/sbin/ifconfig lo up
echo "1" >/proc/sys/net/ipv4/conf/lo/arp_ignore
echo "2" >/proc/sys/net/ipv4/conf/lo/arp_announce
echo "1" >/proc/sys/net/ipv4/conf/all/arp_ignore
echo "2" >/proc/sys/net/ipv4/conf/all/arp_announce
/sbin/sysctl -p >/dev/null 2>&1
/sbin/ifconfig lo:0 $VIP netmask 255.255.255.255 up #在回环地址上绑定VIP，设定掩码，与Direct Server（自身）上的IP保持通信
/sbin/route add -host $VIP dev lo:0
echo "LVS-DR real server starts successfully.n"
;;
stop)
/sbin/ifconfig lo:0 down
/sbin/route del $VIP >/dev/null 2>&1
echo "1" >/proc/sys/net/ipv4/conf/lo/arp_ignore
echo "2" >/proc/sys/net/ipv4/conf/lo/arp_announce
echo "1" >/proc/sys/net/ipv4/conf/all/arp_ignore
echo "2" >/proc/sys/net/ipv4/conf/all/arp_announce
echo "LVS-DR real server stopped.n"
;;
status)
isLoOn=`/sbin/ifconfig lo:0 | grep "$VIP"`
isRoOn=`/bin/netstat -rn | grep "$VIP"`
if [ "$isLoON" == "" -a "$isRoOn" == "" ]; then
echo "LVS-DR real server has run yet."
else
echo "LVS-DR real server is running."
fi
exit 3
;;
*)
echo "Usage: $0 {start|stop|status}"
exit 1
esac
exit 0
　　将lvs脚本加入开机自启动
　　# chmod +x /etc/init.d/realserver
　　# echo "/etc/init.d/realserver" >> /etc/rc.d/rc.local
　　分别启动LVS和keepalived
　　# service realserver start
　　# service keepalived start
　　注意此时网卡的变化，可以看到虚拟网卡已经分配到了realserver上。
　　此时查看LVS集群状态，可以看到集群下有两个Real Server，调度算法，权重等信息。ActiveConn代表当前Real Server的活跃连接数
　　# ipvsadm -ln
　　IP Virtual Server version 1.2.1 (size=4096)
　　Prot LocalAddress:Port Scheduler Flags
　　-> RemoteAddress:Port           Forward Weight ActiveConn InActConn
　　TCP  192.168.1.100:3306 wrr persistent 50
　　-> 192.168.1.5:3306             Route   3      4          1
　　-> 192.168.1.6:3306             Route   3      0          2
　　此时LVS+Keepalived+MySQL主主复制已经搭建完成。
　　测试验证
　　功能性验证
　　关闭MySQL Server2
　　# service mysqld stop
　　在LVS1查看/var/log/messages中关于keepalived日志，LVS1检测到了MySQL Server2宕机，同时LVS集群自动剔除了故障节点
　　Sep  9 13:50:53 192.168.1.2 Keepalived_healthcheckers[18797]: TCP connection to [192.168.1.6]:3306 failed !!!
　　Sep  9 13:50:53 192.168.1.2 Keepalived_healthcheckers[18797]: Removing service [192.168.1.6]:3306 from VS [192.168.1.100]:3306
　　从新启动MySQL Server2后自动将故障节点自动加入LVS集群
　　Sep  9 13:51:41 192.168.1.2 Keepalived_healthcheckers[18797]: TCP connection to [192.168.1.6]:3306 success.
　　Sep  9 13:51:41 192.168.1.2 Keepalived_healthcheckers[18797]: Adding service [192.168.1.6]:3306 to VS [192.168.1.100]:3306
　　关闭LVS1上的Keepalived（模拟宕机操作），查看LVS1上的日志，可以看到Keepalived移出了LVS1上的VIP
　　Sep  9 14:01:27 192.168.1.2 Keepalived[18796]: Stopping Keepalived v1.2.13 (09/09，2014)
　　Sep  9 14:01:27 192.168.1.2 Keepalived_healthcheckers[18797]: Removing service [192.168.1.5]:3306 from VS [192.168.1.100]:3306
　　Sep  9 14:01:27 192.168.1.2 Keepalived_healthcheckers[18797]: Removing service [192.168.1.6]:3306 from VS [192.168.1.100]:3306
　　Sep  9 14:01:27 192.168.1.2 Keepalived_vrrp[18799]: VRRP_Instance(VI_1) sending 0 priority
　　Sep  9 14:01:27 192.168.1.2 Keepalived_vrrp[18799]: VRRP_Instance(VI_1) removing protocol VIPs.
　　同时查看LVS2上日志，可以看到LVS2成为了Master，并接管了VIP
　　Sep  9 14:11:24 192.168.1.11 Keepalived_vrrp[7457]: VRRP_Instance(VI_1) Transition to MASTER STATE
　　Sep  9 14:11:25 192.168.1.11 Keepalived_vrrp[7457]: VRRP_Instance(VI_1) Entering MASTER STATE
　　Sep  9 14:11:25 192.168.1.11 Keepalived_vrrp[7457]: VRRP_Instance(VI_1) setting protocol VIPs.
　　Sep  9 14:11:25 192.168.1.11 Keepalived_vrrp[7457]: VRRP_Instance(VI_1) Sending gratuitous ARPs on eth0 for 192.168.1.100
　　Sep  9 14:11:25 192.168.1.11 Keepalived_healthcheckers[7456]: Netlink reflector reports IP 192.168.1.100 added
　　Sep  9 14:11:25 192.168.1.11 avahi-daemon[1407]: Registering new address record for 192.168.1.100 on eth0.IPv4.
　　Sep  9 14:11:30 192.168.1.11 Keepalived_vrrp[7457]: VRRP_Instance(VI_1) Sending gratuitous ARPs on eth0 for 192.168.1.100
　　在LVS2上查看LVS集群状态，一切正常。
　　# ipvsadm -ln
　　IP Virtual Server version 1.2.1 (size=4096)
　　Prot LocalAddress:Port Scheduler Flags
　　-> RemoteAddress:Port           Forward Weight ActiveConn InActConn
　　TCP  192.168.1.100:3306 wrr persistent 50
　　-> 192.168.1.5:3306             Route   3      2          0
　　-> 192.168.1.6:3306             Route   3      1          0
　　总结
　　MySQL主主复制是集群的基础，组成Server Array，其中每个节点作为Real Server。
　　LVS服务器提供了负载均衡的作用，将用户请求分发到Real Server，一台Real Server故障并不会影响整个集群。
　　Keepalived搭建主备LVS服务器，避免了LVS服务器的单点故障，出现故障时可以自动切换到正常的节点。