keepalived

搭建Keepalived

主节点Keepalived安装

环境：两台nginx服务器

1. 下载Keepalived安装包

curl https://www.keepalived.org/software/keepalived-2.2.7.tar.gz -o keepalived-2.2.7.tar.gz -k 

2. 解压到跟nginx安装包同一个目录下

tar -zxvf keepalived-2.2.7.tar.gz 

3. 配置Keepalived，进入keepalived-2.2.7目录下使用以下命令

./configure \
--prefix=/usr/local/keepalived \ 
--sysconf=/etc  
# prefix  安装目录
# sysconf 核心配置文件

4. 编译和安装

make
make install

5. 启动

cd /usr/local/keepalived/
ll
cd sbin/
./keepalived 

主节点Keepalived核心配置文件

1. 查看IP地址
2. 进入etc/keepalived目录下配置Keepalived.conf文件

cd /etc/keepalived
vim keepalived.conf

修改以下配置

3. 启动keepalived，再查看IP地址，可以发现多了一个IP地址，也就是VIP

备节点配置

1. 把主节点的Keepalived文件复制到备节点上

scp -r /usr/local/keepalived/ root@192.168.206.132:/usr/local/

2. 在备节点查看是否复制成功
   
3. 修改备节点核心配置文件
   
4. 指定配置文件,查看进程

./keepalived -f /usr/local/keepalived/etc/keepalived/keepalived.conf  

5. 查看ip地址，备节点获取不到VIP

6. 关掉主节点配置文件

7. 再次查看备节点IP地址，此时可看到VIP，说明主备切换正常

8. 使用VIP访问，亦可以正常访问

把keepalived注册成为系统服务

1. 关闭keepalived
   
2. 拷贝配置文件

cd keepalived-2.2.7/keepalived/etc/
cp init.d/keepalived /etc/init.d/
cp sysconfig/keepalived /etc/sysconfig/

3. 加载配置文件

systemctl daemon-reload

4. 启动服务查看进程

systemctl start keepalived.service
ps -ef|grep keepalived

keepalived 配置nginx自动重启，实现7X24不间断服务

1. 关闭主节点的nginx，访问VIP，会发现访问失败

./nginx -s stop

2. 编辑脚本文件，进入Keepalived目录下，把脚本文件放在keepalived.conf同一个目录下

cd /etc/keepalived/
vim check_nginx_alive_or_not.sh

#!/bin/bash
A=`ps -C nginx --no-header |wc -l`
#判断nginx是否宕机，如果宕机了，尝试重启
if [ $A -eq 0 ];then
    /usr/local/nginx/sbin/nginx
    #等待一小会再次检查nginx，如果没有启动成功，则停止keepalived，使其启动备用机
    sleep 3
    if [ `ps -C nginx --no-header |wc -l` -eq 0 ];then
        killall keepalived
    fi
fi

3. 给脚本文件添加可执行权限,执行脚本文件

chmod  +x check_nginx_alive_or_not.sh
./check_nginx_alive_or_not.sh

4. 再次访问VIP，可以正常访问
   
5. 配置Keepalived做定时监听，在核心配置文件keepalived.conf下添加以下内容

cd /etc/keepalived/
vim keepalived.conf 

vrrp_script check_nginx_alive {
    script "/etc/keepalived/check_nginx_alive_or_not.sh"
    interval 2 #每隔两秒运行上一行脚本
    weight 10 #如果脚本运行成功，则升级权重+10
}

track_script {
    check_nginx_alive #追踪nginx脚本
}

6. 重启keepalived服务

systemctl restart keepalived.service

7. 测试，关闭nginx服务，依旧可以继续访问VIP