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
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LVS_Master： 182.148.15.237LVS_Backup： 182.148.15.236MySQL1 Real Server： 182.148.15.233MySQL2 Real Server： 182.148.15.238VIP： 182.148.15.239OS: 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
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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 -nIP 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/shVIP=182.148.15.239. /etc/rc.d/init.d/functionscase "$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 $VIP >/dev/null 2>&1 echo "1" >/proc/sys/net/ipv4/conf/lo/arp_ignore echo "2" >/proc/sys/net/ipv4/conf/lo/arp_announce echo "1" >/proc/sys/net/ipv4/conf/all/arp_ignore echo "2" >/proc/sys/net/ipv4/conf/all/arp_announceecho "LVS-DR real server stopped.
" ;;status) isLoOn=`/sbin/ifconfig lo:0 | grep "$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 1esacexit 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 startLVS-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 ~]# ifconfigeth0 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:12）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/shVIP=182.148.15.239. /etc/rc.d/init.d/functionscase "$1" instart) /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 $VIP >/dev/null 2>&1 echo "1" >/proc/sys/net/ipv4/conf/lo/arp_ignore echo "2" >/proc/sys/net/ipv4/conf/lo/arp_announce echo "1" >/proc/sys/net/ipv4/conf/all/arp_ignore echo "2" >/proc/sys/net/ipv4/conf/all/arp_announceecho "LVS-DR real server stopped.
" ;;status) isLoOn=`/sbin/ifconfig lo:0 | grep "$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 1esacexit 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 startLVS-DR real server starts successfully.
[root@MySQL2 ~]# ifconfigeth0 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
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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 restart2）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 keepalivedglobal_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 startStarting 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 -lnIP Virtual Server version 1.2.1 (size=4096)Prot LocalAddress:Port Scheduler Flags -> RemoteAddress:Port Forward Weight ActiveConn InActConnTCP 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 keepalivedglobal_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 startStarting keepalived: [ OK ][root@LVS_Backup ~]# ipvsadm -lnIP Virtual Server version 1.2.1 (size=4096)Prot LocalAddress:Port Scheduler Flags -> RemoteAddress:Port Forward Weight ActiveConn InActConnTCP 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 stopShutting 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 InActConnTCP 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 -lnIP Virtual Server version 1.2.1 (size=4096)Prot LocalAddress:Port Scheduler Flags -> RemoteAddress:Port Forward Weight ActiveConn InActConnTCP 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 stopStopping keepalived: [ OK ] [root@LVS_Master ~]# tail -f /var/log/messages........Apr 26 15:29:38 test3-237 Keepalived[4976]: StoppingApr 26 15:29:38 test3-237 Keepalived_vrrp[4979]: VRRP_Instance(VI_1) sent 0 priorityApr 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]:3306Apr 26 15:29:38 test3-237 Keepalived_healthcheckers[4977]: Removing service [182.148.15.238]:3306 from VS [182.148.15.239]:3306Apr 26 15:29:38 test3-237 Keepalived_healthcheckers[4977]: StoppedApr 26 15:29:38 test3-237 kernel: IPVS: __ip_vs_del_service: enterApr 26 15:29:39 test3-237 Keepalived_vrrp[4979]: StoppedApr 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 forever2: 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 STATEApr 26 15:26:42 test4-236 Keepalived_vrrp[4711]: VRRP_Instance(VI_1) Entering MASTER STATEApr 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 182.148.15.239Apr 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 forever2: 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 -lnIP Virtual Server version 1.2.1 (size=4096)Prot LocalAddress:Port Scheduler Flags -> RemoteAddress:Port Forward Weight ActiveConn InActConnTCP 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 STATEApr 26 15:37:15 test3-237 Keepalived_vrrp[5263]: VRRP_Instance(VI_1) Entering MASTER STATEApr 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 182.148.15.239Apr 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 addr1: 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 forever2: 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 -p123456Welcome to the MySQL monitor. Commands end with ; or g.Your MySQL connection id is 856Server 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 itsaffiliates. Other names may be trademarks of their respectiveowners. 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：
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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。 |