Nginx之Keepalived高可用工具

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1、创建两台虚拟机，分别为主机和从机，区别两台虚拟机的 IP 地址

2、将 keepalived 上传到 linux 系统当中

3、cd /usr/local 目录

4、tar -zxvf keepalived-1.2.18.tar.gz

5、cd keepalived-1.2.18 目录

6、yum install -y openssl openssl-devel (需要安装一个软件包)

7、./configure –prefix=/usr/local/keepalived 编译，将编译文件放到 /usr/local/keepalived

8、make

9、make install

10、在 /etc/keepalived 创建目录：mkdir /etc/keepalived

11、cp /usr/local/keepalived/etc/keepalived/keepalived.conf /etc/keepalived/

12、cp /usr/local/keepalived/etc/rc.d/init.d/keepalived /etc/init.d/

13、cp /usr/local/keepalived/etc/sysconfig/keepalived /etc/sysconfig/

14、ln -s /usr/local/sbin/keepalived /usr/sbin/

（ln -s /usr/local/keepalived/sbin/keepalived /sbin/）

15、将 nginx 启动脚本和 keepalived.conf 配置上传到 /etc/keepalived

16、主机：修改 keepalived.conf 配置文件  vim /etc/keepalived/keepalived.conf

interface 配置成与主机相同的网络 ip a
mcast_src_ip 配置成自己机器的 IP
virtual_ipaddress {
192.168.33.135 # 虚拟 ip, 也就是解决写死程序的 ip 怎么能切换的 ip, 也可扩展，用途广泛。可配置多个。
}

17、启动 keepalived   启动命令 service keepalived start

如果报错：Job for keepalived.service failed because the control process exited with error code. See “systemctl status keepalived.service” and “journalctl -xe” for details.

18、解决办法：rm /usr/sbin/keepalived

19、ln -s /usr/local/keepalived/sbin/keepalived /usr/sbin/

 20、再次启动

21、可以设置开机启动：chkconfig keepalived on

22、自动重启不了，解决办法

23、备机安装步骤同上，备机修改配置文件步骤如下

24、备机：修改 keepalived.conf 配置文件  vim /etc/keepalived/keepalived.conf

 state BACKUP 备机名称
interface 配置成与主机相同的网络 ip a
mcast_src_ip 配置成自己机器的 IP
priority 90  权重配置 
virtual_ipaddress {
192.168.33.135  # 虚拟 ip, 也就是解决写死程序的 ip 怎么能切换的 ip, 也可扩展，用途广泛。可配置多个。
}

25、从机启动步骤同上

26、效果展示  访问虚拟 IP 地址 192.168.33.135

27、模拟主机挂掉，高可用工具 Keepalived 实现自动启动备机，防止宕机

注意：为确保区分主机与备机，在此修改了静态资源 HTML 的标题

  ①、挂掉主机

②、虚拟 IP 地址 192.168.33.135 继续访问备机

③、虚拟 IP 访问效果

④、恢复主机

⑤、虚拟 IP 地址 192.168.33.135 继续访问主机

⑥、虚拟 IP 访问效果

29、keepalived 常用命令

启动 Keepalived：service keepalived start

30、注意事项

区分主机与备机名称、

区分主机与备机 IP 地址、

区分主机与备机的权重  主机权重 > 备机权重