使用keepalive+lvs实现mysql master-master自动故障转移

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1.准备机器，需要至少准备2台机器
3.配置mysql双机master-master实现，不再赘述，参见另一篇mysql mmm的博文
2.安装lvs和keepalived和配置keepalived,参见http://www.keepalived.org/sery-lvs-cluster.pdf，注意lvs的最新版本是1.26,对应的是linux2.6.28以上内核版本，版本需要一致，
否则编译不通过，查看内核版本命令： uname -r
3. 操作说明：
   1). keepalived启动后会自动绑定虚ip到物理网卡上，比如eth0。如果主机不同时是mysql主机不需要realserver脚本。
   2). mysql主机，即不需要keepalived服务的主机，只需要安装lvs模块，并且需要配置realserver脚本，并且需要启动此脚本。
       realserver里配置的虚ip月keepalived里配置的虚ip保持一致，虚ip一定要被绑定到lo上。这是由lvs/dr模式的处理方式决定的。（使用VS/DR方法：调度器和服务器组都必须在物理上有一个网卡通过不分断的局域网相连，如通过交换机或者高速的HUB相连。VIP地址为调度器和服务器组共享，调度器配置的VIP地址是对外可见的，用于接收虚拟服务的请求报文；所有的服务器把VIP地址配置在各自的Non-ARP网络设备上，它对外面是不可见的，只是用于处理目标地址为VIP的网络请求。在VS/DR中，调度器根据各个服务器的负载情况，动态地选择一台服务器，不修改也不封装IP报文，而是将数据帧的MAC地址改为选出服务器的MAC地址，再将修改后的数据帧在与服务器组的局域网上发送。因为数据帧的MAC地址是选出的服务器，所以服务器肯定可以收到这个数据帧，从中可以获得该IP报文。当服务器发现报文的目标地址VIP是在本地的网络设备上，服务器处理这个报文，然后根据路由表将响应报文直接返回给客户。）
   3).keepalived需要安装1.2.1版本，否则sorry server的切换会有问题
   4).自动切换原理是：keepalived realserver列表只配置一台mysql主机，sorry server配置另一台主机，这样在realserver正常情况下，sorry server不会被切换，
      只充当备机，只有realserver出故障时才切换到sorry server，keepalived的sorry server天生具有这个特性。
   5). iptables防火墙配置，keepalived的master与backup之间需要保证心跳，这样才能保证其相互切换，如果iptables不进行特殊配置，则不会正常切换。配置如下：
       -I INPUT -i eth0 -d 224.0.0.0/8 -j ACCEPT
       -A INPUT -p 112 -i eth0 -j ACCEPT
       -A OUTPUT -p 112 -o eth0 -j ACCEPT
4. 具体操作：

1) keepalived master主机和mysql master主机：10.3.1.24
    keepalived backup主机: 10.3.1.18
    mysql slave 主机：10.3.1.23

    虚ip：10.3.1.56

2) keepalived master(10.3.1.24)配置：

        global_defs {
        lvs_id LVS_HA_MASTER
    }
    vrrp_sync_group DBGROUP {
    group {
        VI_MYSQL
       }
    }
    vrrp_instance VI_MYSQL {
          state MASTER
          interface eth0
        lvs_sync_daemon_inteface eth0
          virtual_router_id 59
          priority 200
          advert_int 1
          authentication {
              auth_type PASS
              auth_pass 1111
          }
          virtual_ipaddress {
              10.3.1.56
          }
    }

    virtual_server 10.3.1.56 3306 {
       delay_loop 3
       lb_algo wlc
       lb_kind DR
       # persistence_timeout 20
       protocol TCP

       sorry_server 10.3.1.23 3306

       real_server 127.0.0.1 3306 {
          weight 100
          TCP_CHECK {
            connect_timeout 3
            nb_get_retry 3
            delay_before_retry 3
            connect_port 3306
          }
       }
    }

3) mysql master realserver(10.3.1.24)脚本：

        #!/bin/bash
    #desciription : start realserver
    MYSQLHA=10.3.1.56
    /etc/rc.d/init.d/functions
    case "$1" in
    start)
    echo " start LVS of REALServer"
    /sbin/ifconfig lo:0 $MYSQLHA broadcast $MYSQLHA netmask 255.255.255.255 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
    ;;
    stop)
    /sbin/ifconfig lo:0 down
    echo "close LVS Directorserver"
    echo "0" >/proc/sys/net/ipv4/conf/lo/arp_ignore
    echo "0" >/proc/sys/net/ipv4/conf/lo/arp_announce
    echo "0" >/proc/sys/net/ipv4/conf/all/arp_ignore
    echo "0" >/proc/sys/net/ipv4/conf/all/arp_announce
    ;;
    *)
    echo "Usage: $0 {start|stop}"
    exit 1
    esac
4) keepalived backup（10.3.1.18）配置：

       global_defs {
        lvs_id LVS_HA_BACKUP #注意这儿与master不同
    }
    vrrp_sync_group DBGROUP {
    group {
        VI_MYSQL
       }
    }
    vrrp_instance VI_MYSQL {
          state BACKUP #注意这儿，与master不同
          interface eth0
          lvs_sync_daemon_inteface eth0
          virtual_router_id 59
          priority 100   #注意这儿，与master不同
          advert_int 1
          authentication {
              auth_type PASS
              auth_pass 1111
          }
          virtual_ipaddress {
              10.3.1.56
          }
    }

    virtual_server 10.3.1.56 3306 {
       delay_loop 3
       lb_algo wlc
       lb_kind DR
       # persistence_timeout 20
       protocol TCP

       sorry_server 10.3.1.23 3306

       real_server 10.3.1.24 3306 {
          weight 100
          TCP_CHECK {
            connect_timeout 3
            nb_get_retry 3
            delay_before_retry 3
            connect_port 3306
          }
       }
    }

5) mysql slave realserver(10.3.1.23)脚本：

        #!/bin/bash
    #desciription : start realserver
    MYSQLHA=10.3.1.56
    /etc/rc.d/init.d/functions
    case "$1" in
    start)
    echo " start LVS of REALServer"
    /sbin/ifconfig lo:0 $MYSQLHA broadcast $MYSQLHA netmask 255.255.255.255 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
    ;;
    stop)
    /sbin/ifconfig lo:0 down
    echo "close LVS Directorserver"
    echo "0" >/proc/sys/net/ipv4/conf/lo/arp_ignore
    echo "0" >/proc/sys/net/ipv4/conf/lo/arp_announce
    echo "0" >/proc/sys/net/ipv4/conf/all/arp_ignore
    echo "0" >/proc/sys/net/ipv4/conf/all/arp_announce
    ;;
    *)
    echo "Usage: $0 {start|stop}"
    exit 1
    esac

6). 防火墙配置：

   vi /etc/sysconfig/iptables

   add:
   -I INPUT -i eth0 -d 224.0.0.0/8 -j ACCEPT
   -A INPUT -p 112 -i eth0 -j ACCEPT
   -A OUTPUT -p 112 -o eth0 -j ACCEPT

   保存后重启：service iptables restart

7).启动

keepalive master: service keepalived start
mysql master: /usr/local/bin/realserver start

调用ip add 命令会看到:

1: lo: <LOOPBACK,UP,LOWER_UP> mtu 16436 qdisc noqueue
    link/loopback 00:00:00:00:00:00 brd 00:00:00:00:00:00
    inet 127.0.0.1/8 scope host lo
    inet 10.3.1.56/32 brd 10.3.1.56 scope global lo:0
    inet6 ::1/128 scope host
       valid_lft forever preferred_lft forever
2: eth0: <BROADCAST,MULTICAST,UP,LOWER_UP> mtu 1500 qdisc pfifo_fast qlen 1000
    link/ether f4:ce:46:b4:35:40 brd ff:ff:ff:ff:ff:ff
    inet 10.3.1.24/8 brd 10.255.255.255 scope global eth0
    inet 10.3.1.56/32 scope global eth0
    inet6 fe80::f6ce:46ff:feb4:3540/64 scope link
       valid_lft forever preferred_lft forever
3: eth1: <BROADCAST,MULTICAST> mtu 1500 qdisc noop qlen 1000
    link/ether f4:ce:46:b4:35:44 brd ff:ff:ff:ff:ff:ff
4: sit0: <NOARP> mtu 1480 qdisc noop
    link/sit 0.0.0.0 brd 0.0.0.0

keepalived backup启动： service keepalived start

调用ip add 命令会看到:
1: lo: <LOOPBACK,UP,LOWER_UP> mtu 16436 qdisc noqueue
    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 qlen 1000
    link/ether f4:ce:46:89:63:98 brd ff:ff:ff:ff:ff:ff
    inet 10.3.1.18/8 brd 10.255.255.255 scope global eth0
    inet6 fe80::f6ce:46ff:fe89:6398/64 scope link
       valid_lft forever preferred_lft forever
3: eth1: <BROADCAST,MULTICAST> mtu 1500 qdisc noop qlen 1000
    link/ether f4:ce:46:89:63:9c brd ff:ff:ff:ff:ff:ff
4: sit0: <NOARP> mtu 1480 qdisc noop
    link/sit 0.0.0.0 brd 0.0.0.0

注意不会绑定任何ip

msyql slave: /usr/local/bin/realserver start

调用ip add 命令会看到:

1: lo: <LOOPBACK,UP,LOWER_UP> mtu 16436 qdisc noqueue
    link/loopback 00:00:00:00:00:00 brd 00:00:00:00:00:00
    inet 127.0.0.1/8 scope host lo
    inet 10.3.1.56/32 brd 10.3.1.56 scope global lo:0
    inet6 ::1/128 scope host
       valid_lft forever preferred_lft forever
2: eth0: <BROADCAST,MULTICAST,UP,LOWER_UP> mtu 1500 qdisc pfifo_fast qlen 1000
    link/ether f4:ce:46:b4:31:58 brd ff:ff:ff:ff:ff:ff
    inet 10.3.1.23/8 brd 10.255.255.255 scope global eth0
    inet6 fe80::f6ce:46ff:feb4:3158/64 scope link
       valid_lft forever preferred_lft forever
3: eth1: <BROADCAST,MULTICAST> mtu 1500 qdisc noop qlen 1000
    link/ether f4:ce:46:b4:31:5c brd ff:ff:ff:ff:ff:ff
4: sit0: <NOARP> mtu 1480 qdisc noop
    link/sit 0.0.0.0 brd 0.0.0.0