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keepalived-高可用

keepalived-高可用

作者: 酷酷的伟 | 来源:发表于2019-06-15 19:34 被阅读0次

    keepalived高可用原理

    keepalived高可用对之间是通过VRRP协议通信
    1、VRRP协议，中文名为虚拟路由冗余协议，VRRP的出现是为了解决静态路由的单点故障。
    2、VRRP是通过一种竞选机制来将路由任务交给某台VRRP路由器的。
    3、VRRP是用过IP多播的方式（默认多播地址（224.0.0.18））实现高可用对之间通信的。
    4、工作时主节点发包，备节点接包，当备节点接收不到主节点发的数据包的时候，就启动接管程序，接管主节点的资源。备节点可以有多个，通过优先级竞选，但一般keepalived系统运维工作中都是一对。
    5、VRRP使用了加密协议加密数据，但keepalived官方目前还是推荐使用明文的方式配置认证类型和密码。
    <meta charset="utf-8">

    1.准备环境

    1. 准备机器lb01 lb02 web01 web02
    2. lb01 lb02 安装软件
      yum install keepalived -y
    [root@lb01 nginx]# rpm -qa keepalived 
keepalived-1.3.5-8.el7_6.x86_64

[root@lb02 ~]# rpm -qa keepalived 
keepalived-1.3.5-8.el7_6.x86_64

    2.开启服务与自启动

    lb01:
[root@lb01 nginx]# systemctl start keepalived.service 
[root@lb01 nginx]# systemctl enable keepalived.service 

lb02:
[root@lb02 ~]# systemctl start keepalived.service 
[root@lb02 ~]# systemctl enable keepalived.service

    2.利用Wireshark抓包

    image

    随便抓个包看看：

    image

    3.配置文件

    /etc/keepalived/keepalived.conf

    image

    配置文件格式：

    修改前将源配置文件备份

    [root@lb01 nginx]# vim  /etc/keepalived/keepalived.conf
! Configuration File for keepalived

global_defs {
    router_id lb01
}

vrrp_instance VI_1 {
    state MASTER
    interface eth0
    virtual_router_id 51
    priority 150
    advert_int 1
    authentication {
        auth_type PASS
        auth_pass 1111
    }
    virtual_ipaddress {
     10.0.0.3/24 dev eth0 label eth0:1  
    }
}

    4.lb01与lb02的keepalived配置文件

    image.png
    image

    测试一下

    主关闭后，备接管
    主恢复后，优先级高于备，自动跳转回来

    image

    主

    image

    备

    image

    keepalived基于服务器，nginx挂了不会自动切换如何解决

    1.检查状态

    ps -ef |grep keepalived

    关闭不了nginx服务的方法

    1.restart
2\. pkill nginx  
3\. restart

    2.写脚本

    脚本名字不要写服务的名字，如nginx.sh
    检查nginx状态
    nginx关闭，keepalived也关闭

    [root@lb01 nginx]# vim /server/scripts/jiancha.sh 
#!/bin/bash
. /etc/profile
count=` ps -ef|grep nginx |grep -v grep |wc -l `

if [ $count -eq 0 ];then
  systemctl stop keepalived
fi

    3.一定要给脚本添加执行权限

    [root@lb01 nginx]# sh /server/scripts/jiancha.sh

    4.添加函数

    vrrp_script jiancha {   #脚本名称
script "/server/scripts/jiancha.sh"  #定义检查的脚本
interval 2  #每隔2秒执行
weight 1    #权重分配数量


    track_script {  #执行脚本
jiancha     #脚本名称
}

    5. 完整书写

    [root@lb01 nginx]# vim /etc/keepalived/keepalived.conf
! Configuration File for keepalived

global_defs {
    router_id lb01
}
vrrp_script jiancha {
script "/server/scripts/jiancha.sh"
interval 2
weight 1
}

vrrp_instance VI_1 {
    state MASTER
    interface eth0
    virtual_router_id 51
    priority 150
    advert_int 1
    authentication {
        auth_type PASS
        auth_pass 1111
    }
    virtual_ipaddress {
     10.0.0.3/24 dev eth0 label eth0:1
    }
    track_script {
    jiancha
    }
}

    6.测试一下

    [root@lb01 nginx]# systemctl is-active nginx
active
[root@lb01 nginx]# ip a|grep 0.3
    inet 10.0.0.3/24 scope global secondary eth0:1
[root@lb01 nginx]# systemctl stop nginx
[root@lb01 nginx]# ip a|grep 0.3
[root@lb01 nginx]#  \\虚拟ip跳走了
[root@lb01 nginx]#

    7.去lb02看一下是否跳过去了

    [root@lb02 ~]# ip a|grep 0.3
    inet 10.0.0.3/24 scope global secondary eth0:1

    8.回到lb01把nginx和keepalived开启

    [root@lb01 nginx]# systemctl start nginx
[root@lb01 nginx]# ip a|grep 0.3
[root@lb01 nginx]# systemctl start keepalived.service 
[root@lb01 nginx]# ip a|grep 0.3    #间隔2秒
[root@lb01 nginx]#
[root@lb01 nginx]# ip a|grep 0.3
    inet 10.0.0.3/24 scope global secondary eth0:1
#又转到主了

    keepalived双主模式

    image.png

    修改配置文件后重启keepalived
    systemctl restart keepalived

    image.png

    lb01的keepalived双主配置文件

    ! Configuration File for keepalived

global_defs {
    router_id lb01
}
vrrp_script jiancha {
script "/server/scripts/jiancha.sh"
interval 2
weight 1
}

vrrp_instance VI_1 {
    state MASTER
    interface eth0
    virtual_router_id 51
    priority 150
    advert_int 1
    authentication {
        auth_type PASS
        auth_pass 1111
    }
    virtual_ipaddress {
     10.0.0.3/24 dev eth0 label eth0:1  
    }
    track_script {
    jiancha
    }
}
vrrp_instance VI_2 {
    state BACKUP
    interface eth0
    virtual_router_id 52
    priority 100
    advert_int 1
    authentication {
        auth_type PASS
        auth_pass 1111
    }
    virtual_ipaddress {
     10.0.0.4/24 dev eth0 label eth0:2
    }
}

    lb02的keepalived双主配置文件

    ! Configuration File for keepalived

global_defs {
    router_id lb02
}

vrrp_instance VI_1 {   
    state BACKUP
    interface eth0
    virtual_router_id 51
    priority 100
    advert_int 1
    authentication {
        auth_type PASS
        auth_pass 1111
    }
    virtual_ipaddress {
     10.0.0.3/24 dev eth0 label eth0:1  
    }
}
vrrp_instance VI_2 {
    state MASTER
    interface eth0
    virtual_router_id 52
    priority 150
    advert_int 1
    authentication {
        auth_type PASS
        auth_pass 1111
    }
    virtual_ipaddress {
     10.0.0.4/24 dev eth0 label eth0:2
    }
}

    让lb01和lb02的nginx配置文件相同

    vim /etc/nginx/nginx.conf  :

     upstream  web_pools {
     server 10.0.0.7:80 weight=1 max_fails=3 fail_timeout=10s;
     server 10.0.0.8:80 weight=1 max_fails=3 fail_timeout=10s;
     }
#    include /etc/nginx/conf.d/*.conf;
     server {
     listen 80;
     server_name www.oldboy.com;
     location / {
         proxy_pass http://web_pools;
         proxy_set_header Host $host;
         proxy_set_header X-Forwarded-For $remote_addr; 
        }
     }
     server {
     listen 80;
     server_name blog.oldboy.com;
     location / {
         proxy_pass http://web_pools;
         proxy_set_header Host $host;
         proxy_set_header X-Forwarded-For $remote_addr;
        }
     }

    curl一下

    保证俩边的/etc/nginx/nginx.conf配置文件一样

    [root@lb01 nginx]# curl 10.0.0.3
web01 www.oldboy.com
[root@lb01 nginx]# curl 10.0.0.3
web02 www.oldboy.com
[root@lb01 nginx]# curl 10.0.0.3
web01 www.oldboy.com
[root@lb01 nginx]# 
[root@lb01 nginx]# curl 10.0.0.4
web01 www.oldboy.com
[root@lb01 nginx]# curl 10.0.0.4
web02 www.oldboy.com
[root@lb01 nginx]# curl 10.0.0.4
web01 www.oldboy.com

    每个域名绑定对应ip

    1.基于ip的虚拟主机

    添加虚拟主机的ip就可以了
    listen 10.0.0.3:80;
    listen 10.0.0.4:80;

    lb01和lb02的修改相同
         upstream  web_pools {
     server 10.0.0.7:80 weight=1 max_fails=3 fail_timeout=10s;
     server 10.0.0.8:80 weight=1 max_fails=3 fail_timeout=10s;
     }
#    include /etc/nginx/conf.d/*.conf;
     server {
     listen 10.0.0.3:80;  ##添加虚拟主机的ip
     server_name www.oldboy.com;
     location / {
         proxy_pass http://web_pools;
         proxy_set_header Host $host;
         proxy_set_header X-Forwarded-For $remote_addr;
        }
     }
     server {
     listen 10.0.0.4:80;  #添加虚拟主机的ip
     server_name blog.oldboy.com;
     location / {
         proxy_pass http://web_pools;
         proxy_set_header Host $host;
         proxy_set_header X-Forwarded-For $remote_addr;
        }
     }
}
------------------------------------------------------------
nginx -t
nginx: the configuration file /etc/nginx/nginx.conf syntax is ok
nginx: configuration file /etc/nginx/nginx.conf test is successful

systemctl restart nginx

    2.重启检查语法nginx报错问题

    image
    修改内核参数：net.ipv4.ip_nonlocal_bind = 1

    sysctl -p #生效

    [root@lb01 nginx]# tail -1 /etc/sysctl.conf 
net.ipv4.ip_nonlocal_bind = 1
[root@lb01 nginx]# sysctl -p  #生效
net.ipv4.ip_nonlocal_bind = 1

[root@lb02 ~]# tail -1 /etc/sysctl.conf 
net.ipv4.ip_nonlocal_bind = 1
[root@lb02 ~]# sysctl -p  #生效
net.ipv4.ip_nonlocal_bind = 1

    再重启就可以了

    [root@lb01 nginx]# nginx -t
nginx: the configuration file /etc/nginx/nginx.conf syntax is ok
nginx: configuration file /etc/nginx/nginx.conf test is successful
[root@lb01 nginx]# systemctl restart nginx

    3.内核参数修改了哪些内容

    net.ipv4.ip_nonlocal_bind = 1

    [root@lb01 nginx]# sysctl -p
net.ipv4.ip_nonlocal_bind = 1
[root@lb01 nginx]# #cat /proc/sys/net/ipv4/ip_nonlocal_bind 
[root@lb01 nginx]# #net.ipv4.ip_nonlocal_bind = 1
[root@lb01 nginx]# cat /proc/sys/net/ipv4/ip_nonlocal_bind 
1

    高可用的裂脑(脑裂)问题

    image image image

    while死循环语法

    [root@lb02 ~]# cat /server/scripts/chk_vip.sh
#!/bin/bash
while true
do
 date
sleep 2; 
done
[root@lb02 ~]# sh /server/scripts/chk_vip.sh
Mon Jun 17 12:01:19 CST 2019
Mon Jun 17 12:01:21 CST 2019
Mon Jun 17 12:01:23 CST 2019
Mon Jun 17 12:01:25 CST 2019
Mon Jun 17 12:01:27 CST 2019
Mon Jun 17 12:01:29 CST 2019
Mon Jun 17 12:01:31 CST 2019

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