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）

Mysql双主热备+LVS+Keepalived高可用操作记录

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

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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.\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

[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.\n

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.\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.\n

[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

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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

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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

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。