Nginx+keepalived 双机热备（主主模式）

之前已经介绍了Nginx+Keepalived双机热备的主从模式，今天在此基础上说下主主模式的配置。

由之前的配置信息可知：
master机器（master-node）：103.110.98.14/192.168.1.14      VIP1:103.110.98.20
slave机器（slave-node）：103.110.98.24/192.168.1.24       VIP2:103.110.98.21

主主模式需要两个负载均衡的VIP，
之前设置了VIP（103.110.98.20）
所以还需要设置另一个VIP（103.110.98.21）

修改keepalived的配置

1）master负载机上的keepalived配置：（注意，这里是双主配置，MASTER-BACKUP和BACKUP-MASTER;如果是多主，比如三主，就是MATER-BACKUP-BACKUP、BACKUP-MASTER-BACKUP和BACKUP-BACKUP-MASTER）
注意：
配置中的虚拟路由标识virtual_router_id在MASTER和BACKUP处配置不能一样（但在主从模式下配置是一样的）

[root@master-node ~]# vim /etc/keepalived/keepalived.conf
! Configuration File for keepalived     

global_defs {
notification_email {
ops@wangshibo.cn
tech@wangshibo.cn
}

notification_email_from ops@wangshibo.cn
smtp_server 127.0.0.1
smtp_connect_timeout 30
router_id master-node
}

vrrp_script chk_http_port {
    script "/opt/chk_nginx.sh"
    interval 2
    weight -5
    fall 2
    rise 1
}

vrrp_instance VI_1 {
    state MASTER
    interface em1
    mcast_src_ip 103.110.98.14
    virtual_router_id 51
    priority 101
    advert_int 1
    authentication {
        auth_type PASS
        auth_pass 1111
    }

track_script {
   chk_http_port
}

virtual_ipaddress {
    103.110.98.20
}

notify_master "/etc/keepalived/clean_arp.sh 103.110.98.20"
}

vrrp_instance VI_2 {
    state BACKUP
    interface em1
    mcast_src_ip 103.110.98.24
    virtual_router_id 52
    priority 99
    advert_int 1
    authentication {
        auth_type PASS
        auth_pass 1111
    }

track_script {
   chk_http_port
}
virtual_ipaddress {
    103.110.98.21
    }
notify_master "/etc/keepalived/clean_arp.sh 103.10.86.21"
}

[root@master-node ~]# vim /etc/keepalived/clean_arp.sh         //更新vip的arp记录到网关（注意脚本中的网卡别填错了，要跟vip所在网卡一致）
#!/bin/sh
VIP=$1
GATEWAY=103.110.98.1                                                         //负载均衡器的公网网关地址
/sbin/arping -I em1 -c 5 -s $VIP $GATEWAY &>/dev/null
[root@master-node ~]# chmod 755 /etc/keepalived/clean_arp.sh

2）slave负载机上的keepalived配置：

[root@slave-node ~]# vim /etc/keepalived/keepalived.conf
! Configuration File for keepalived     

global_defs {
notification_email {
ops@wangshibo.cn
tech@wangshibo.cn
}

notification_email_from ops@wangshibo.cn
smtp_server 127.0.0.1
smtp_connect_timeout 30
router_id slave-node
}

vrrp_script chk_http_port {
    script "/opt/chk_nginx.sh"
    interval 2
    weight -5
    fall 2
    rise 1
}

vrrp_instance VI_1 {
    state BACKUP
    interface em1
    mcast_src_ip 103.110.98.14
    virtual_router_id 51
    priority 99
    advert_int 1
    authentication {
        auth_type PASS
        auth_pass 1111
    }

track_script {
   chk_http_port
}

virtual_ipaddress {
    103.110.98.20
}

notify_master "/etc/keepalived/clean_arp.sh 103.110.98.20"
}

vrrp_instance VI_2 {
    state MASTER
    interface em1
    mcast_src_ip 103.110.98.24
    virtual_router_id 52
    priority 101
    advert_int 1
    authentication {
        auth_type PASS
        auth_pass 1111
    }

track_script {
   chk_http_port
}
virtual_ipaddress {
    103.110.98.21
    }
notify_master "/etc/keepalived/clean_arp.sh 21"
}

[root@slave-node ~]# vim /etc/keepalived/clean_arp.sh
#!/bin/sh
VIP=$1
GATEWAY=103.110.98.1
/sbin/arping -I em1 -c 5 -s $VIP $GATEWAY &>/dev/null
[root@slave-node ~]# chmod 755 /etc/keepalived/clean_arp.sh

重启master和slave负载机的keepalive（保证两台机器的ngixn和keepalived服务都启动）
[root@master-node ~]# /etc/init.d/keepalived restart
[root@slave-node ~]# /etc/init.d/keepalived restart

将nginx中配置的域名解析到这两个VIP地址上：
103.110.98.20 dev.wangshibo.com
103.110.98.21 dev.wangshibo.com

浏览器访问是正常的（如果master或slave有一台宕机，或其中一个VIP故障，只要另一台是正常的就行）

关闭两台负载机其中一台的keepalived服务，那么它的VIP就会自动漂移到另一台机器上。
关闭两台机器的nginx，会自动重启（前提是keepalived服务要启动）！对网站域名的访问丝毫不受影响。

[root@master-node ~]# pkill -9 nginx
root 32365 9775 0 19:04 pts/0 00:00:00 grep --color=auto nginx
[root@master-node ~]# ps -ef|grep nginx
root 32367 9775 0 19:04 pts/0 00:00:00 grep --color=auto nginx
[root@master-node ~]# ps -ef|grep nginx
root 32369 32368 0 19:04 ? 00:00:00 /bin/bash /opt/chk_nginx.sh
root 32374 1 0 19:04 ? 00:00:00 nginx: master process /usr/local/nginx/sbin/nginx
www 32376 32374 1 19:04 ? 00:00:00 nginx: worker process
www 32377 32374 1 19:04 ? 00:00:00 nginx: worker process
www 32378 32374 1 19:04 ? 00:00:00 nginx: worker process
www 32379 32374 1 19:04 ? 00:00:00 nginx: worker process
www 32380 32374 1 19:04 ? 00:00:00 nginx: worker process
www 32381 32374 1 19:04 ? 00:00:00 nginx: worker process
www 32382 32374 1 19:04 ? 00:00:00 nginx: worker process
www 32383 32374 1 19:04 ? 00:00:00 nginx: worker process
www 32384 32374 0 19:04 ? 00:00:00 nginx: cache manager process
www 32385 32374 0 19:04 ? 00:00:00 nginx: cache loader process
root 32387 9775 0 19:04 pts/0 00:00:00 grep --color=auto nginx