keepalived切换实例 keepalived模式

高可用有2中方式。

1、Nginx+keepalived 主从配置

这种方案，使用一个vip地址，前端使用2台机器，一台做主，一台做备，但同时只有一台机器工作，另一台备份机器在主机器不出现故障的时候，永远处于浪费状态，对于服务器不多的网站，该方案不经济实惠。

2、Nginx+keepalived 双主配置

这种方案，使用两个vip地址，前端使用2台机器，互为主备，同时有两台机器工作，当其中一台机器出现故障，两台机器的请求转移到一台机器负担，非常适合于当前架构环境。

1、Nginx+keepalived 主从配置

1.环境如下

lb-01:192.168.96.130  nginx+keepalived-master
lb-02:192.168.96.131  nginx+keepalived-backup
VIP：192.168.75.135

nginx+tomcat负载均衡集群参照 nginx+tomcat负载均衡集群参照

两台机器都要安装nginx 配置文件相同

<span style="font-size:18px;">upstream myServer{    
      server 192.168.96.130:8080;    
      server 192.168.96.131:8080;    
    }   
 server {  
        listen       80;  
        server_name  localhost;  
  
        #charset koi8-r;  
  
        #access_log  logs/host.access.log  main;  
  
        location / {   
          proxy_pass  http://myServer;    
        }  
  </span>

nginx结合keepalived高可用

为什么使用keepalived呢？使用keepalived就用来做高可用的，提供虚拟VIP

分别在2台机子上安装keepalived

# yum install keepalived -y

查看keepalived版本

# keepalived -v
Keepalived v1.2.13 (11/20,2015)

关于2台keepalived配置文件/etc/keepalived

在130master keepalived配置文件内容如下

<span style="font-size:18px;">global_defs {
   notification_email {
     [e-mail]
     [e-mail]
     [e-mail]
   }
   notification_email_from [e-mail]
   smtp_server 192.168.200.1
   smtp_connect_timeout 30
   router_id LVS_DEVEL
}

vrrp_script chk_http_port {

   script "/usr/local/src/check_nginx_pid.sh"

   interval 2      #（检测脚本执行的间隔）

   weight 2

}

vrrp_instance VI_1 {
    state MASTER   # 备份服务器上将 MASTER 改为 BACKUP  
    interface eno16777736  //网卡
    virtual_router_id 51   # 主、备机的virtual_router_id必须相同
    priority 100     # 主、备机取不同的优先级，主机值较大，备份机值较小
    advert_int 1
    authentication {
        auth_type PASS
        auth_pass 1111
    }
    virtual_ipaddress {
        192.168.96.138  // VRRP H虚拟地址
    }
}
</span>

在131-backup keepalived配置文件内容如下

<span style="font-size:18px;">global_defs {
   notification_email {
     [e-mail]
     [e-mail]
     [e-mail]
   }
   notification_email_from [e-mail]
   smtp_server 192.168.200.1
   smtp_connect_timeout 30
   router_id LVS_DEVEL
}

vrrp_script chk_http_port {

   script "/usr/local/src/check_nginx_pid.sh"

   interval 2      #（检测脚本执行的间隔）

   weight 2

}

vrrp_instance VI_1 {
    state BACKUP
    interface eno16777736
    virtual_router_id 51
    priority 90
    advert_int 1
    authentication {
        auth_type PASS
        auth_pass 1111
    }
    virtual_ipaddress {
        192.168.96.138
    }
}</span>

然后分别启动2台keepalived服务

[root@lb-01 ~]# systemctl start keepalived.service

[root@lb-02 ~]# systemctl start keepalived.service

查看虚拟VIP

130-master机器查看

从上面可以看到虚拟VIP地址192.168.96.138

131-backup机器查看

从上面可以看到没有虚拟VIP地址

测试访问虚拟VIP

打开浏览器访问

此时虚拟VIP可以轮询访问了

模拟故障

把130-master nginx和keepalived停止查看是否还能正常提供服务

[root@lb-01 sbin]# ./nginx -s stop
[root@lb-01 sbin]# systemctl stop keepalived.service

此时虚拟VIP已经不再master上了

客户端打开浏览器访问是否正常访问

130nginx和keepalived挂了也不影响服务

查看131backup机器VIP情况

此时虚拟VIP 已经在131机器上

那么如何实现nginx+keepalived双主模式呢？

1.其实只是需要更改下keepalived配置文件即可，配置文件实例如下

增加新的VIP192.168.96.139,192.168.75.138是130机器上主虚拟VIP，192.168.96.139是131机器上主虚拟VIP

130的keepalived配置文件内容如下

! Configuration File for keepalived

global_defs {
   notification_email {
     [e-mail]
     [e-mail]
     [e-mail]
   }
   notification_email_from [e-mail]
   smtp_server 192.168.200.1
   smtp_connect_timeout 30
   router_id LVS_DEVEL
}

vrrp_script chk_http_port {

   script "/usr/local/src/check_nginx_pid.sh"

   interval 2      #（检测脚本执行的间隔）

   weight 2

}

vrrp_instance VI_1 {
    state MASTER
    interface eno16777736
    virtual_router_id 51
    priority 100
    advert_int 1
    authentication {
        auth_type PASS
        auth_pass 1111
    }
    virtual_ipaddress {
        192.168.96.138
    }
}

vrrp_instance VI_2 {
    state BACKUP
    interface eno16777736
    virtual_router_id 52
    priority 90
    advert_int 1
    authentication {
        auth_type PASS
        auth_pass 1111
    }
    virtual_ipaddress {
        192.168.96.139
    }
}

131

的keepalived配置文件内容如下

! Configuration File for keepalived

global_defs {
   notification_email {
     [e-mail]
     [e-mail]
     [e-mail]
   }
   notification_email_from [e-mail]
   smtp_server 192.168.200.1
   smtp_connect_timeout 30
   router_id LVS_DEVEL
}

vrrp_script chk_http_port {

   script "/usr/local/src/check_nginx_pid.sh"

   interval 2      #（检测脚本执行的间隔）

   weight 2

}

vrrp_instance VI_1 {
    state BACKUP
    interface eno16777736
    virtual_router_id 51
    priority 90
    advert_int 1
    authentication {
        auth_type PASS
        auth_pass 1111
    }
    virtual_ipaddress {
        192.168.96.138
    }
}


vrrp_instance VI_2 {
    state MASTER
    interface eno16777736
    virtual_router_id 52
    priority 100
    advert_int 1
    authentication {
        auth_type PASS
        auth_pass 1111
    }
    virtual_ipaddress {
        192.168.96.139
    }
}

分别启动2台lb上nginx和keepalived服务

[root@lb-01 sbin]# ./nginx
[root@lb-01 sbin]# systemctl start keepalived.service

130查看虚拟ip

131查看虚拟ip

客户端测试访问虚拟VIP

访问虚拟VIP:192.168.96.138结果如下

访问虚拟VIP:192.168.96.139结果如下

模拟故障

把130服务停止

查看130虚拟VIP是否存在结果如下

没了

测试访问虚拟VIP**

从上面结果可以看到，即使130机器发生了故障也不影响使用，这样也利用131资源了

此时查看一下131虚拟ip结果情况如下

注：此时虚拟VIP地址都已经在lb-02机器上了