MySQL 双主热备 + LVS + Keepalived 高可用操作记录

MySQL复制能够保证数据的冗余的同时可以做读写分离来分担系统压力，如果是主主复制还可以很好的避免主节点的单点故障。然而MySQL主主复制存在一些问题无法满足我们的实际需要：未提供统一访问入口来实现负载均衡，如果其中master宕掉的话需要手动切换到另外一个master，而不能自动进行切换。前面介绍了Mysql+Keepalived双主热备高可用方案记录，那篇文档里没有使用到LVS（实现负载均衡），而下面要介绍的就是如何通过Keepalived+LVS方式来是实现MySQL的高可用性，利用LVS实现MySQL的读写负载均衡，Keepalived避免节点出现单点故障，同时解决以上问题。

Keepalived是一个基于VRRP（虚拟路由冗余协议）可用来实现服务高可用性的软件方案，避免出现单点故障。Keepalived一般用来实现轻量级高可用性，且不需要共享存储，一般用于两个节点之间，常见有LVS+Keepalived、Nginx+Keepalived组合。

LVS(Linux Virtual Server)是一个高可用性虚拟的服务器集群系统。本项目在1998年5月由章文嵩博士成立，是中国国内最早出现的自由软件项目之一。LVS主要用于多服务器的负载均衡，作用于网络层。LVS构建的服务器集群系统中，前端的负载均衡层被称为Director Server；后端提供服务的服务器组层被称为Real Server。通过下图可以大致了解LVS的基础架构。

LVS有三种工作模式，分别是：
1）DR（Direct Routing 直接路由）模式。 DR可以支持相当多的Real Server，但需要保证Director Server（分发器）虚拟网卡与物理网卡在同一网段，并且后端Real Server的vip要建立在本地回环口lo设备上，这样做是为了防止ip冲突；DR模式的好处是进站流量经过Director Server，出站流量不经过Director Server，减轻了Director Server的负载压力。
2）NAT（Network Address Translation 网络地址转换）模式。NAT扩展性有限，无法支持更多的Real Server，因为所有的请求包和应答包都需要Director Server进行解析再生，这样就很影响效率。
3）TUN(Tunneling IP隧道）模式。TUN模式能够支持更多的Real Server，但需要所有服务器支持IP隧道协议；

LVS负载均衡有10中调度算法，分别是：rr（轮询）、wrr（加权轮询）、lc、wlc、lblc、lblcr、dh、sh、sed、nq

以下详细记录了Mysql在主主同步环境下，利用LVS实现Mysql的读写负责均衡以及使用Keepalived心跳测试避免节点出现单点故障，实现故障转移的高可用。
1）高可用方案的环境准备

LVS_Master：           182.148.15.237
LVS_Backup：           182.148.15.236
MySQL1 Real Server：   182.148.15.233
MySQL2 Real Server：   182.148.15.238
VIP：                  182.148.15.239
OS:                    CentOS 6.8

温馨提示：LVS_Master和LVS_Backup充当的是Director Server分发器的角色。
这里的LVS采用DR模式，即"进站流量经过Director Server分发器，出站流量不经过分发器"，这就要求：
1）LVS_Master和LVS_Backup需要将VIP绑定在其正常提供服务的网卡上（这里指182.48.115.0网段所在的网卡），netmask和对于网卡设备一致。
2）后端的Real Server要在本地回环口lo上绑定vip（防止ip冲突）

2）环境部署记录如下
a）Mysql主主热备环境部署
MySQL1 Real Server1和MySQL2 Real Server的主主热备可以参考Mysql+Keepalived双主热备高可用操作记录中对应部分。

b）Keepalived安装
LVS_Master和LVS_Backup的keepalived安装，也可以参考Mysql+Keepalived双主热备高可用操作记录中对应部分。

c）LVS安装

LVS_Master和LVS_Backup两台机器安装步骤一样
 
首先打开两台机器的ip_forward转发功能
[root@LVS_Master ~]# echo "1" > /proc/sys/net/ipv4/ip_forward

先下载ipvsadm
[root@LVS_Master ~]# cd /usr/local/src/
[root@LVS_Master src]# wget http://www.linuxvirtualserver.org/software/kernel-2.6/ipvsadm-1.26.tar.gz
 
需要安装以下软件包
[root@LVS_Master src]# yum install -y libnl* popt*
 
查看是否加载lvs模块
[root@LVS_Master src]# modprobe -l |grep ipvs
 
解压安装
[root@LVS_Master src]# ln -s /usr/src/kernels/2.6.32-431.5.1.el6.x86_64/ /usr/src/linux
[root@LVS_Master src]# tar -zxvf ipvsadm-1.26.tar.gz
[root@LVS_Master src]# cd ipvsadm-1.26
[root@LVS_Master ipvsadm-1.26]# make && make install
 
LVS安装完成，查看当前LVS集群
[root@LVS_Master ipvsadm-1.26]# ipvsadm -L -n
IP Virtual Server version 1.2.1 (size=4096)
Prot LocalAddress:Port Scheduler Flags
  -> RemoteAddress:Port           Forward Weight ActiveConn InActConn

d）编写LVS启动脚本/etc/init.d/realserver

1）在MySQL1 Real Server服务器上的操作
[root@MySQL1 ~]# vim /etc/init.d/realserver
#!/bin/sh
VIP=182.148.15.239
. /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.
"
    ;;
stop)
    /sbin/ifconfig lo:0 down
    /sbin/route del $VIP >/dev/null 2>&1
    echo "1" >/proc/sys/net/ipv4/conf/lo/arp_ignore
    echo "2" >/proc/sys/net/ipv4/conf/lo/arp_announce
    echo "1" >/proc/sys/net/ipv4/conf/all/arp_ignore
    echo "2" >/proc/sys/net/ipv4/conf/all/arp_announce
echo "LVS-DR real server stopped.
"
    ;;
status)
    isLoOn=`/sbin/ifconfig lo:0 | grep "$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
[root@MySQL1 ~]# chmod +x /etc/init.d/realserver
[root@MySQL1 ~]# echo "/etc/init.d/realserver" >> /etc/rc.d/rc.local

启动LVS脚本
[root@MySQL1 ~]# service realserver start
LVS-DR real server starts successfully.


查看MySQL1 Real Server服务器，发现VIP已经成功绑定到本地回环口lo上了
[root@MySQL1 ~]# ifconfig
eth0      Link encap:Ethernet  HWaddr 52:54:00:D1:27:75  
          inet addr:182.148.15.233  Bcast:182.148.15.255  Mask:255.255.255.224
          inet6 addr: fe80::5054:ff:fed1:2775/64 Scope:Link
          UP BROADCAST RUNNING MULTICAST  MTU:1500  Metric:1
          RX packets:598406 errors:0 dropped:0 overruns:0 frame:0
          TX packets:12050 errors:0 dropped:0 overruns:0 carrier:0
          collisions:0 txqueuelen:1000 
          RX bytes:78790653 (75.1 MiB)  TX bytes:33151764 (31.6 MiB)

lo        Link encap:Local Loopback  
          inet addr:127.0.0.1  Mask:255.0.0.0
          inet6 addr: ::1/128 Scope:Host
          UP LOOPBACK RUNNING  MTU:65536  Metric:1
          RX packets:483 errors:0 dropped:0 overruns:0 frame:0
          TX packets:483 errors:0 dropped:0 overruns:0 carrier:0
          collisions:0 txqueuelen:0 
          RX bytes:55807 (54.4 KiB)  TX bytes:55807 (54.4 KiB)

lo:0      Link encap:Local Loopback  
          inet addr:182.148.15.239  Mask:255.255.255.255
          UP LOOPBACK RUNNING  MTU:65536  Metric:1


2）在MySQL2 Real Server服务器上的操作
[root@MySQL2 ~]# vim /etc/init.d/realserver       //这个脚本在后端Real Server上都是一样的内容
#!/bin/sh
VIP=182.148.15.239
. /etc/rc.d/init.d/functions

case "$1" in

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 
    /sbin/route add -host $VIP dev lo:0
    echo "LVS-DR real server starts successfully.
"
    ;;
stop)
    /sbin/ifconfig lo:0 down
    /sbin/route del $VIP >/dev/null 2>&1
    echo "1" >/proc/sys/net/ipv4/conf/lo/arp_ignore
    echo "2" >/proc/sys/net/ipv4/conf/lo/arp_announce
    echo "1" >/proc/sys/net/ipv4/conf/all/arp_ignore
    echo "2" >/proc/sys/net/ipv4/conf/all/arp_announce
echo "LVS-DR real server stopped.
"
    ;;
status)
    isLoOn=`/sbin/ifconfig lo:0 | grep "$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并启动lvs脚本
[root@MySQL2 ~]# chmod +x /etc/init.d/realserver
[root@MySQL2 ~]# echo "/etc/init.d/realserver" >> /etc/rc.d/rc.local
[root@MySQL2 ~]# service realserver start
LVS-DR real server starts successfully.



[root@MySQL2 ~]# ifconfig
eth0      Link encap:Ethernet  HWaddr 52:54:00:3B:33:8F  
          inet addr:182.148.15.238  Bcast:182.148.15.255  Mask:255.255.255.224
          inet6 addr: fe80::5054:ff:fe3b:338f/64 Scope:Link
          UP BROADCAST RUNNING MULTICAST  MTU:1500  Metric:1
          RX packets:135305 errors:0 dropped:0 overruns:0 frame:0
          TX packets:11256 errors:0 dropped:0 overruns:0 carrier:0
          collisions:0 txqueuelen:1000 
          RX bytes:17338566 (16.5 MiB)  TX bytes:892363 (871.4 KiB)

lo        Link encap:Local Loopback  
          inet addr:127.0.0.1  Mask:255.0.0.0
          inet6 addr: ::1/128 Scope:Host
          UP LOOPBACK RUNNING  MTU:65536  Metric:1
          RX packets:0 errors:0 dropped:0 overruns:0 frame:0
          TX packets:0 errors:0 dropped:0 overruns:0 carrier:0
          collisions:0 txqueuelen:0 
          RX bytes:0 (0.0 b)  TX bytes:0 (0.0 b)

lo:0      Link encap:Local Loopback  
          inet addr:182.148.15.239  Mask:255.255.255.255
          UP LOOPBACK RUNNING  MTU:65536  Metric:1

e）配置iptables防火墙

1）后端两台机器MySQL1 Real Server和MySQL2 Real Server要在iptables里开放3306端口
[root@MySQL1 ~]# vim /etc/sysconfig/iptables
......
-A INPUT -m state --state NEW -m tcp -p tcp --dport 3306 -j ACCEPT

[root@MySQL1 ~]# /etc/init.d/iptables restart

2）LVS_Master和LVS_Backup两台机器要在iptables开放VRRP组播地址的相关规则。
   注意：这个一定要设置！！！否则会出现故障时的VIP资源漂移错乱问题！

[root@LVS_Master ~]# vim /etc/sysconfig/iptables       //两台LVS机器都要设置
.......
-A INPUT -s 182.148.15.0/24 -d 224.0.0.18 -j ACCEPT        //允许组播地址通信
-A INPUT -s 182.148.15.0/24 -p vrrp -j ACCEPT              //允许VRRP（虚拟路由器冗余协）通信
-A INPUT -m state --state NEW -m tcp -p tcp --dport 3306 -j ACCEPT 

[root@LVS_Master ~]# /etc/init.d/iptables restart

3）接着配置LVS+Keepalived配置

1）LVS_Master上的操作
[root@LVS_Master ~]# vim /etc/keepalived/keepalived.conf
! Configuration File for keepalived

global_defs {
   router_id LVS_Master
}

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 {
        182.148.15.239         #VIP
    }
}

virtual_server 182.148.15.239 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就是MySQL连接端口
    real_server 182.148.15.233 3306 {
        weight 3  ##权重
        TCP_CHECK {
            connect_timeout 3
            nb_get_retry 3
            delay_before_retry 3
            connect_port 3306
        }
    }
    real_server 182.148.15.238 3306 {
        weight 3
        TCP_CHECK {
            connect_timeout 3
            nb_get_retry 3
            delay_before_retry 3
            connect_port 3306
        }
    }
}

启动keepalived
[root@LVS_Master ~]# /etc/init.d/keepalived start
Starting keepalived:                                       [  OK  ]

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。
[root@LVS_Master ~]# ipvsadm -ln
IP Virtual Server version 1.2.1 (size=4096)
Prot LocalAddress:Port Scheduler Flags
  -> RemoteAddress:Port           Forward Weight ActiveConn InActConn
TCP  182.148.15.239:3306 wrr persistent 50
  -> 182.148.15.233:3306          Route   3      1          0         
  -> 182.148.15.238:3306          Route   3      0          0  

2）LVS_Backup上的操作
[root@LVS_Backup ~]# vim /etc/keepalived/keepalived.conf
! Configuration File for keepalived

global_defs {
   router_id LVS_Backup
}

vrrp_instance VI_1 {
    state BACKUP              
    interface eth0             
    virtual_router_id 51       
    priority 90               
    advert_int 1              
    authentication {
        auth_type PASS         
        auth_pass 1111         
    }
    virtual_ipaddress {
        182.148.15.239         
    }
}

virtual_server 182.148.15.239 3306 {
    delay_loop 6              
    lb_algo wrr               
    lb_kind DR                 

    persistence_timeout 50     
    protocol TCP             

    real_server 182.148.15.233 3306 {
        weight 3  
        TCP_CHECK {
            connect_timeout 3
            nb_get_retry 3
            delay_before_retry 3
            connect_port 3306
        }
    }
    real_server 182.148.15.238 3306 {
        weight 3
        TCP_CHECK {
            connect_timeout 3
            nb_get_retry 3
            delay_before_retry 3
            connect_port 3306
        }
    }
}


启动keepalived
[root@LVS_Backup ~]# /etc/init.d/keepalived start
Starting keepalived:                                       [  OK  ]

[root@LVS_Backup ~]# ipvsadm -ln
IP Virtual Server version 1.2.1 (size=4096)
Prot LocalAddress:Port Scheduler Flags
  -> RemoteAddress:Port           Forward Weight ActiveConn InActConn
TCP  182.148.15.239:3306 wrr persistent 50
  -> 182.148.15.233:3306          Route   3      0          0         
  -> 182.148.15.238:3306          Route   3      0          0  

此时LVS+Keepalived+MySQL主主复制已经搭建完成。

4）最后进行测试验证

1）先进行功能性验证
a）关闭MySQL2 Real Server服务器上的mysql
[root@MySQL2 ~]# /etc/init.d/mysql stop
Shutting down MySQL.. SUCCESS!
 
在LVS_Master查看/var/log/messages中关于keepalived日志，LVS_Master检测到了MySQL2 Real Server服务器宕机，同时LVS集群自动剔除了故障节点
[root@LVS_Master ~]# tail -f /var/log/messages
.......
Apr 26 15:22:19 test3-237 Keepalived_healthcheckers[4606]: TCP connection to [182.148.15.238]:3306 failed.
Apr 26 15:22:19 test3-237 Keepalived_vrrp[4608]: Sending gratuitous ARP on eth0 for 182.148.15.239
.......
 
[root@LVS_Master ~]# ipvsadm -ln         //LVS已经将MySQL2 Real Server剔除
IP Virtual Server version 1.2.1 (size=4096)
Prot LocalAddress:Port Scheduler Flags
  -> RemoteAddress:Port           Forward Weight ActiveConn InActConn
TCP  182.148.15.239:3306 wrr persistent 50
  -> 182.148.15.233:3306          Route   3      1          0
 
从新启动MySQL2 Real Server后自动将故障节点自动加入LVS集群
[root@LVS_Master ~]# tail -f /var/log/messages
.......
Apr 26 15:23:49 test3-237 Keepalived_healthcheckers[4606]: TCP connection to [182.148.15.238]:3306 success.
Apr 26 15:23:49 test3-237 Keepalived_healthcheckers[4606]: Adding service [182.148.15.238]:3306 to VS [182.148.15.239]:3306
.......
 
[root@LVS_Master ~]# ipvsadm -ln
IP Virtual Server version 1.2.1 (size=4096)
Prot LocalAddress:Port Scheduler Flags
  -> RemoteAddress:Port           Forward Weight ActiveConn InActConn
TCP  182.148.15.239:3306 wrr persistent 50
  -> 182.148.15.233:3306          Route   3      1          0        
  -> 182.148.15.238:3306          Route   3      1          0
 
 
b）关闭LVS_Master上的Keepalived（模拟宕机操作），查看LVS_Master上的日志，可以看到Keepalived移出了LVS1上的VIP
[root@LVS_Master ~]# /etc/init.d/keepalived stop
Stopping keepalived:                                       [  OK  ]
 
[root@LVS_Master ~]# tail -f /var/log/messages
........
Apr 26 15:29:38 test3-237 Keepalived[4976]: Stopping
Apr 26 15:29:38 test3-237 Keepalived_vrrp[4979]: VRRP_Instance(VI_1) sent 0 priority
Apr 26 15:29:38 test3-237 Keepalived_vrrp[4979]: VRRP_Instance(VI_1) removing protocol VIPs.
Apr 26 15:29:38 test3-237 Keepalived_healthcheckers[4977]: Removing service [182.148.15.233]:3306 from VS [182.148.15.239]:3306
Apr 26 15:29:38 test3-237 Keepalived_healthcheckers[4977]: Removing service [182.148.15.238]:3306 from VS [182.148.15.239]:3306
Apr 26 15:29:38 test3-237 Keepalived_healthcheckers[4977]: Stopped
Apr 26 15:29:38 test3-237 kernel: IPVS: __ip_vs_del_service: enter
Apr 26 15:29:39 test3-237 Keepalived_vrrp[4979]: Stopped
Apr 26 15:29:39 test3-237 Keepalived[4976]: Stopped Keepalived v1.3.5 (03/19,2017), git commit v1.3.5-6-g6fa32f2
 
[root@LVS_Master ~]# ip addr    //发现VIP资源已经不在本机了
1: lo: <LOOPBACK,UP,LOWER_UP> mtu 65536 qdisc noqueue state UNKNOWN
    link/loopback 00:00:00:00:00:00 brd 00:00:00:00:00:00
    inet 127.0.0.1/8 scope host lo
    inet6 ::1/128 scope host
       valid_lft forever preferred_lft forever
2: eth0: <BROADCAST,MULTICAST,UP,LOWER_UP> mtu 1500 qdisc pfifo_fast state UP qlen 1000
    link/ether 52:54:00:68:dc:b6 brd ff:ff:ff:ff:ff:ff
    inet 182.148.15.237/27 brd 182.148.15.255 scope global eth0
    inet 182.148.15.239/27 brd 182.148.15.255 scope global secondary eth0:0
    inet6 fe80::5054:ff:fe68:dcb6/64 scope link
       valid_lft forever preferred_lft forever
 
 
同时查看LVS_Backup上日志，可以看到LVS_Backup成为了Master，并接管了VIP
[root@LVS_Backup ~]# tail -f /var/log/messages
.....
Apr 26 15:26:41 test4-236 Keepalived_vrrp[4711]: VRRP_Instance(VI_1) Transition to MASTER STATE
Apr 26 15:26:42 test4-236 Keepalived_vrrp[4711]: VRRP_Instance(VI_1) Entering MASTER STATE
Apr 26 15:26:42 test4-236 Keepalived_vrrp[4711]: VRRP_Instance(VI_1) setting protocol VIPs.
Apr 26 15:26:42 test4-236 Keepalived_vrrp[4711]: Sending gratuitous ARP on eth0 for 182.148.15.239
Apr 26 15:26:42 test4-236 Keepalived_vrrp[4711]: VRRP_Instance(VI_1) Sending/queueing gratuitous ARPs on eth0 for 182.148.15.239
 
[root@LVS_Backup ~]# ip addr         //发现VIP资源已经转移到LVS_Backup机器上了
1: lo: <LOOPBACK,UP,LOWER_UP> mtu 65536 qdisc noqueue state UNKNOWN
    link/loopback 00:00:00:00:00:00 brd 00:00:00:00:00:00
    inet 127.0.0.1/8 scope host lo
    inet6 ::1/128 scope host
       valid_lft forever preferred_lft forever
2: eth0: <BROADCAST,MULTICAST,UP,LOWER_UP> mtu 1500 qdisc pfifo_fast state UP qlen 1000
    link/ether 52:54:00:90:ac:0f brd ff:ff:ff:ff:ff:ff
    inet 182.148.15.236/27 brd 182.148.15.255 scope global eth0
    inet 182.148.15.239/32 scope global eth0
    inet6 fe80::5054:ff:fe90:ac0f/64 scope link
       valid_lft forever preferred_lft forever
 
在LVS_Backup上查看LVS集群状态，一切正常。
[root@LVS_Backup ~]# ipvsadm -ln
IP Virtual Server version 1.2.1 (size=4096)
Prot LocalAddress:Port Scheduler Flags
  -> RemoteAddress:Port           Forward Weight ActiveConn InActConn
TCP  182.148.15.239:3306 wrr persistent 50
  -> 182.148.15.233:3306          Route   3      0          0        
  -> 182.148.15.238:3306          Route   3      1          1
 
 
接着恢复LVS_Master上的Keepalived，发现VIP资源又会重新从LVS_Backup上转移回来。即LVS_Master重新接管服务。
[root@LVS_Master ~]# tail -f /var/log/messages
.......
Apr 26 15:37:14 test3-237 Keepalived_vrrp[5263]: VRRP_Instance(VI_1) Transition to MASTER STATE
Apr 26 15:37:15 test3-237 Keepalived_vrrp[5263]: VRRP_Instance(VI_1) Entering MASTER STATE
Apr 26 15:37:15 test3-237 Keepalived_vrrp[5263]: VRRP_Instance(VI_1) setting protocol VIPs.
Apr 26 15:37:15 test3-237 Keepalived_vrrp[5263]: Sending gratuitous ARP on eth0 for 182.148.15.239
Apr 26 15:37:15 test3-237 Keepalived_vrrp[5263]: VRRP_Instance(VI_1) Sending/queueing gratuitous ARPs on eth0 for 182.148.15.239
 
[root@LVS_Master ~]# ip addr
1: lo: <LOOPBACK,UP,LOWER_UP> mtu 65536 qdisc noqueue state UNKNOWN
    link/loopback 00:00:00:00:00:00 brd 00:00:00:00:00:00
    inet 127.0.0.1/8 scope host lo
    inet6 ::1/128 scope host
       valid_lft forever preferred_lft forever
2: eth0: <BROADCAST,MULTICAST,UP,LOWER_UP> mtu 1500 qdisc pfifo_fast state UP qlen 1000
    link/ether 52:54:00:68:dc:b6 brd ff:ff:ff:ff:ff:ff
    inet 182.148.15.237/27 brd 182.148.15.255 scope global eth0
    inet 182.148.15.239/32 scope global eth0
    inet 182.148.15.239/27 brd 182.148.15.255 scope global secondary eth0:0
    inet6 fe80::5054:ff:fe68:dcb6/64 scope link
       valid_lft forever preferred_lft forever
 
-----------------------------------------------------------------------------------------
2）接着进行mysql主主热备的高可用
在MySQL1 Real Server和MySQL2 Real Server两台机器的mysql里授权，使远程客户机能正常连接。
 
mysql> grant all on *.* to test@'%' identified by "123456";
Query OK, 0 rows affected (0.03 sec)
 
mysql> flush privileges;
 
经测试发现，对于上面的功能验证，不管是LVS_Master的keepalived关闭（宕机）还是后端MySQL2 Real Serve的mysql关闭，在远程客户机上都能正常连接mysql（通过VIP进行连接）（LVS_Master的keepalived关闭时，如若远程客户机在连接mysql中，可以断开重新连接一次即可）
[root@bastion-IDC ~]# mysql -h182.148.15.239 -utest -p123456
Welcome to the MySQL monitor.  Commands end with ; or g.
Your MySQL connection id is 856
Server version: 5.6.34-log Source distribution
 
Copyright (c) 2000, 2013, Oracle and/or its affiliates. All rights reserved.
 
Oracle is a registered trademark of Oracle Corporation and/or its
affiliates. Other names may be trademarks of their respective
owners.
 
Type 'help;' or 'h' for help. Type 'c' to clear the current input statement.
 
mysql> select * from huanqiu.haha;
+----+-----------+
| id | name      |
+----+-----------+
|  1 | wangshibo |
|  2 | guohuihui |
| 22 | huihui    |
| 23 | bobo      |
+----+-----------+
4 rows in set (0.00 sec)

总结几点：
1）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。
2）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的。
3）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。
4）VRRP虚拟IP地址和接口实际IP必须在同一个网段内，VRRP两个实际接口不在同一网段，是不能形成主备关系的。因为：

VRRP的形式是组播（多播），这个和广播基本一个原理，只不过缩小了范围，让几个服务器能收到，众所周知广播必须在2层里面实现，出3层就出了广播域了。
VRRP中的ip切换是靠arp欺骗实现的，否则vip从主切到备得断多少机器，arp欺骗也是没法在出了3层以外的2个机器直接做的。