双主模式nginx + keepalived配置（双机互为主备）

配置nginx+keepalived的双主机双机热备，这种配置下有两个Virtual IP，两个机器互为主备，最后我们把域名DNS服务器解析至两个Virtual IP即可。

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环境介绍

两台服务器

Server1：192.168.30.61 
Server2：192.168.30.62

要设置的两个虚拟IP

Virtual IP1：192.168.30.51 
Virtual IP2：192.168.30.52

将DNS域名解析至两个虚拟IP： 192.168.30.51、192.168.30.52

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网络扑拓图

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配置第一台服务器

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第一台服务器ip为192.168.30.61

vi /etc/keepalived/keepalived.conf

配置内容如下：

global_defs
{
    notification_email
    {
       [email protected]
    }
    notification_email_from [email protected]
    smtp_server 127.0.0.1
    stmp_connect_timeout 30
    router_id LVS_DEVEL
}

vrrp_script Monitor_Nginx {
    script "/usr/local/keepalived/scripts/monitor_nginx.sh"
    interval 2
    weight 2
}

# 虚拟IP1, 本机作为Master
vrrp_instance VI_1 {
    state MASTER
    interface enp0s3
    virtual_router_id 51
    priority 100
    advert_int 1
    track_interface {
        enp0s3
    }

    authentication {
        auth_type PASS
        auth_pass 123456
    }
    virtual_ipaddress {
        192.168.30.51
    }i
    track_script {
        Monitor_Nginx
    }

}

# 虚拟IP2, 本机作为Backup
vrrp_instance VI_2 {
    state BACKUP
    interface enp0s3
    virtual_router_id 52
    priority 100
    advert_int 1
    track_interface {
        enp0s3
    }

    authentication {
        auth_type PASS
        auth_pass 123456
    }
    virtual_ipaddress {
        192.168.30.52
    }
    track_script {
        Monitor_Nginx
    }

}

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配置第二台服务器

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第二台服务器ip为192.168.30.62

vi /etc/keepalived/keepalived.conf

配置内容如下：

global_defs
{
    notification_email
    {
       [email protected]
    }
    notification_email_from [email protected]
    smtp_server 127.0.0.1
    stmp_connect_timeout 30
    router_id LVS_DEVEL
}

vrrp_script Monitor_Nginx {
    script "/usr/local/keepalived/scripts/monitor_nginx.sh"
    interval 2
    weight 2
}

# 虚拟IP1, 本机作为BACKUP
vrrp_instance VI_1 {
    state BACKUP
    interface enp0s3
    virtual_router_id 51
    priority 100
    advert_int 1
    track_interface {
        enp0s3
    }

    authentication {
        auth_type PASS
        auth_pass 123456
    }
    virtual_ipaddress {
        192.168.30.51
    }
    track_script {
        Monitor_Nginx
    }
}

# 虚拟IP2, 本机作为Master
vrrp_instance VI_2 {
    state MASTER
    interface enp0s3
    virtual_router_id 52
    priority 100
    advert_int 1
    track_interface {
        enp0s3
    }

    authentication {
        auth_type PASS
        auth_pass 123456
    }
    virtual_ipaddress {
        192.168.30.52
    }
    track_script {
        Monitor_Nginx
    }

}

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监控脚本

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和之前的监控脚本一样

# 监控nginx进程，若nginx主进程不存在则启动nginx
# 若5s后nginx进程还是不存在的话kill掉keepalived进程,防止nginx没运行该主机的keepalived还接管虚拟IP
#!/bin/bash
if [ "$(ps -ef | grep "nginx: master process"| grep -v grep )" == "" ]
        then
        /usr/local/nginx/sbin/nginx
        sleep 5
        if [ "$(ps -ef | grep "nginx: master process"| grep -v grep )" == "" ]
        then
                  killall keepalived
        fi
fi

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测试

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修改nginx默认访问页nginx的默认页面

# nginx 默认访问页面
$NGINX_HOME/html/index.html

修改server1的页，加入IP： 192.168.30.61

Welcome to nginx! 192.168.30.61 
If you see this page, the nginx web server is successfully installed and
working. Further configuration is required.

For online documentation and support please refer to
nginx.org.

Commercial support is available at
nginx.com.

Thank you for using nginx.

server2同理

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两个机器都启动keepalived和nginx

访问虚拟ip1

在浏览器输入192.168.30.51进入访问页面 

访问虚拟ip2

在浏览器输入192.168.30.52进入访问页面 

证明两个VIP都起效果了

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Kill掉server2的keepalived

pkill keepalived

• 访问ip2

证明了server1为server2的备机，server2 down掉后server1接管server1的nginx访问

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Kill掉server1机器的keepalived，启动server2机器的keepalived

• 访问ip1

证明了server2为server1的备机，server1 down掉后server1接管server1的nginx访问

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有关nginx和keepalived的安装可参考

• Linux下安装nginx
• 使用keepalived来实现nginx的高可用