实验环境

两台CentOS-7.5虚拟机

web1：10.0.11.203

web2：10.0.11.204

VIP ：10.0.11.210

web类型：nginx

客户端：自用笔记本(win10)

nginx状态检测脚本：ck_nginx.sh

实验一、使用keepalived简单实现web集群的高可用功能

1、准备两台web服务器

1)web1网卡情况

[root@CentOS ~]#

[root@CentOS ~]# ip a

2)web2网卡情况

[root@CentOS-2 ~]#

[root@CentOS-2 ~]# ip a

3)安装nginx

web1端：

[root@CentOS ~]#

[root@CentOS ~]# yum install nginx

[root@CentOS ~]# rpm -qa nginx

nginx-1.16.1-1.el7.x86_64

[root@CentOS ~]#

[root@CentOS ~]#

[root@CentOS ~]# > /usr/share/nginx/html/index.html #清空默认网页

[root@CentOS ~]# echo web1 > /usr/share/nginx/html/index.html #让网页显示web1

[root@CentOS ~]# cat /usr/share/nginx/html/index.html

web1

[root@CentOS ~]#

[root@CentOS ~]# systemctl start nginx #启动nginx

[root@CentOS ~]# systemctl enable nginx #设置nginx开机自启动

C:\Users\Administrator>curl 10.0.11.203

web2端：

[root@CentOS-2 ~]#

[root@CentOS-2 ~]# yum install nginx

[root@CentOS-2 ~]# rpm -qa nginx

nginx-1.16.1-1.el7.x86_64

[root@CentOS-2 ~]#

[root@CentOS-2 ~]#

[root@CentOS-2 ~]# > /usr/share/nginx/html/index.html

[root@CentOS-2 ~]# echo web2 > /usr/share/nginx/html/index.html

[root@CentOS-2 ~]# cat /usr/share/nginx/html/index.html

web2

[root@CentOS-2 ~]#

[root@CentOS-2 ~]# systemctl start nginx

[root@CentOS-2 ~]# systemctl enable nginx

C:\Users\Administrator>curl 10.0.11.204

4)安装keepalived

说明：两台web服务器都需要安装keepalived服务

web1端：

[root@CentOS ~]#

[root@CentOS ~]# yum install keepalived

[root@CentOS ~]# rpm -qa keepalived

keepalived-1.3.5-16.el7.x86_64

[root@CentOS ~]#

web2端：

[root@CentOS-2 ~]#

[root@CentOS-2 ~]# yum install keepalived

[root@CentOS-2 ~]# rpm -qa keepalived

keepalived-1.3.5-16.el7.x86_64

[root@CentOS-2 ~]#

5)配置两台keepalived并启动

web1端：

[root@CentOS ~]#

[root@CentOS ~]# > /etc/keepalived/keepalived.conf #清空原来的配置

[root@CentOS ~]# vim /etc/keepalived/keepalived.conf #编辑配置文件，自定义keepalived配置文件

[root@CentOS ~]# cat /etc/keepalived/keepalived.conf

[root@CentOS ~]#

[root@CentOS ~]# systemctl start keepalived #启动

[root@CentOS ~]# systemctl enable keepalived #设置开机启动

web2端：

[root@CentOS-2 ~]#

[root@CentOS-2 ~]# > /etc/keepalived/keepalived.conf

[root@CentOS-2 ~]# vim /etc/keepalived/keepalived.conf

[root@CentOS-2 ~]# cat /etc/keepalived/keepalived.conf

[root@CentOS-2 ~]#

[root@CentOS-2 ~]# systemctl start keepalived #启动

[root@CentOS-2 ~]# systemctl enable keepalived #设置开机启动

3、测试访问

方法：用客户端通过VIP测试访问web

C:\Users\Administrator>curl 10.0.11.210 #个人笔记本通过VIP测试访问web

拔掉web1服务器的网线，用客户端通过VIP测试访问web：

C:\Users\Administrator>curl 10.0.11.210

再次将web1服务器的网线接好，用客户端通过VIP测试访问web：

C:\Users\Administrator>curl 10.0.11.210

4、实验一结论：

1)利用keepalived成功实现了web服务器集群的高可用

2)虽然可以实现在服务器发生异常高故障的情况下web的高可用，但是遗憾的是此时无法实现针对web服务异常故障所引发的主备高可用切换；因为keepalived无法感知nginx服务的运行状态和健康状态。

实验二、使用keepalived结合nginx监控检测脚本实现更加灵活的高可用集群功能

实验环境：基于实验一的环境，以实验一的环境为基础进行

与实验一的唯一区别：需要准备nginx的健康状态检测脚本

1、编写nginx的健康检测脚本

web1端执行：

[root@CentOS ~]#

[root@CentOS ~]# vim /etc/keepalived/ck_nginx.sh #编写keepalived检测nginx健康状态的脚本

#!/bin/bash

#检查ngin进程是否存在

counter=$(ps -C nginx --no-heading|wc -l)

if [ "${counter}"="0" ]; then

#尝试启动一次ngnx,停止5秒后再次检测

systemctl start nginx

sleep 5

counter=$(ps -C nginx --no-heading|wc -l)

if [ "${counter}"="0" ]; then

#如果启动没成功,就杀掉keepave触发主备切换

systemctl stop nginx

fi

fi

[root@CentOS ~]#

[root@CentOS ~]# cat /etc/keepalived/ck_nginx.sh #查看脚本内容

[root@CentOS ~]#

[root@CentOS ~]# chmod +x /etc/keepalived/ck_nginx.sh #授予脚本可执行权限

[root@CentOS ~]#

web2端执行：

[root@CentOS-2 ~]#

[root@CentOS-2 ~]# vim /etc/keepalived/ck_nginx.sh

#!/bin/bash

#检查ngin进程是否存在

counter=$(ps -C nginx --no-heading|wc -l)

if [ "${counter}"="0" ]; then

#尝试启动一次ngnx,停止5秒后再次检测

systemctl start nginx

sleep 5

counter=$(ps -C nginx --no-heading|wc -l)

if [ "${counter}"="0" ]; then

#如果启动没成功,就杀掉keepave触发主备切换

systemctl stop nginx

fi

fi

[root@CentOS-2 ~]#

[root@CentOS-2 ~]#

[root@CentOS-2 ~]# cat /etc/keepalived/ck_nginx.sh

[root@CentOS-2 ~]#

[root@CentOS-2 ~]# chmod +x /etc/keepalived/ck_nginx.sh

[root@CentOS-2 ~]#

2、编辑修改nginx的配置文件

web1端：

[root@CentOS ~]#

[root@CentOS ~]# vim /etc/keepalived/keepalived.conf #自定义配置文件

! Configuration File for keepalived

vrrp_script chk_nginx {

script "/etc/keepalived/ck_nginx.sh"

interval 2

weight -5

fail 3

}

vrrp_instance VI_1 {

state MASTER

interface ens32

mcast_src_ip 10.0.11.203

virtual_router_id 55

priority 100

advert_int 1 authentication {

auth_type PASS

auth_pass 123456

}

virtual_ipaddress {

10.0.11.210/24

}

track_script {

chk_nginx

}

}

[root@CentOS ~]#

[root@CentOS ~]# systemctl restart keepalived #重启keepalived使配置生效

[root@CentOS ~]#

web2端：

[root@CentOS-2 ~]#

[root@CentOS-2 ~]# vim /etc/keepalived/keepalived.conf #自定义配置文件

! Configuration File for keepalived

vrrp_script chk_nginx {

script "/etc/keepalived/ck_nginx.sh"

interval 2

weight -5

fail 3

}

vrrp_instance VI_1 {

state MASTER

interface ens32

mcast_src_ip 10.0.11.204

virtual_router_id 55

priority 95

advert_int 1 authentication {

auth_type PASS

auth_pass 123456

}

virtual_ipaddress {

10.0.11.210/24

}

track_script {

chk_nginx

}

}

[root@CentOS-2 ~]#

[root@CentOS-2 ~]#

[root@CentOS-2 ~]# systemctl restart keepalived #重启keepalived使配置生效

测试keepalived功能：

由于脚本内容里边，nginx服务在停止以后会立马自启动，所以我们模拟服务器异常关闭导致nginx服务没有办法实现自启动

[root@CentOS ~]#

[root@CentOS ~]# init 0 #关闭web1服务器

[root@CentOS-2 ~]#

[root@CentOS-2 ~]# ping 10.0.11.203 #用web2去pingweb1，发现web1已经被关闭

此时使用客户端去测试验证keepalived功能：

C:\Users\Administrator>curl 10.0.11.210 #用客户端通过VIP去访问web服务器

3、实验二结论

使用keepalived服务结合nginx健康状态检测脚本成功实现了对web服务器集群的高可用