Keepalived安装配置，建立Nginx高可用

1.解压
tar -zxvf keepalived-2.0.18.tar.gz
2.操压后进入到解压出来的目录，看到会有configure，那么就可以配置了(配置安装和nginx一样）
3.使用 configure命令配置安装目录与核心配置文件所在位置：

./configure --prefix=/usr/local/keepalived --sysconf=
/etc

prefix:keepalived安装的位置
sysconf:keepalved核心配置文件所在位置，固定位置，改成其他位量则koepalved启动不了，/var/log/messages中会报错
3.1 配置过程中可能会出现警告值息，如下所示:

***WARNING - this build will not support IPVS with IPv6.Please install libnl/libnl-3 dev libraries to support IPv6 with IPVS.

3.2.安波libnl/libnl-3依赖

yum -y install libnl libnl-devel

3.3.重新configure一下，此时OK.
4.安装keepalived

make && make install

5.进入到/etc/keepalived，该目录下为keepalived核心配置文件

配置Keepalived - 主节点
1.通过命令vim keepalived.conf打开配置文件

global_defs {
	#路由id:当前安装keepalived的节点主机标识符，保证全局唯一
	 router_id keep_171
}
vrrp_instance VI_1 {
	# 表示状态是MASTER主机还是备用机BACKUP 
	state MASTER
	# 该实例绑定的网卡 
	interface ens33
	# 保证主备节点一致即可 
	virtual_router_id 51
	# 权重，master权重一般高于backup，如果有多个，那就是选举，谁的权重高，谁就当选 
	priority 100
	# 主备之间同步检查时间间隔，单位秒 
	advert_int 2
	# 认证权限密码，防止非法节点进入 
	authentication (
		auth_type PASS
		auth_pass 1111
	}
	# 虚拟出来的ip，可以有多个(vip) 
	virtual_ipaddress{192.168.1.161}
}

查看网卡名称

2.启动Keepalived
在sbin目录下进行启动（同nginx），如下图：

3.查看进程

ps -ef | grep keepalived

3.查看虚拟ip
在网卡ens33下，多了一个192.168.1.161，这个就是虚拟ip

1.通过命令 vim keepalived.conf打开配置文件

global_defs{
	router_id keep_172
}
vrrp_instance VI_1 {
	#备用机设置为BACKUP
	state BACKUP 
	interface ens33
	virtual_router_id 51
	#权重低于MASTER 
	priority 80
	advert_int 2
	authentication(
		auth_type PASS
		auth_pass 1111
	}
	virtual_ipaddress {
	#注意:主备两台的vip都是一样的，绑定到同一个虚拟ip
		192.168.1.161
	}
}

2.启动 Keepalived

#启动keepalived
systemctl start keepalived
#停止keepalived
systemctl stop keepalived
#重启keepalived
systemctl restart keepalived

3.查看进程

ps -ef | grep keepalived

1.增加Nginx重启检测脚本

vim /etc/keepalived/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

增加运行权限

chmod +x /etc/keepalived/check_nginx_alive_or_not.sh

2.配置keepalived监听nginx脚本

vrrp_script check_nginx_alive {
	script "/etc/keepalived/check_nginx_alive_or_ not.sh"
	interval 2 # 每限两秒运行上一行脚本
	weight 10 # 如果脚本运行失败，则升级权重+10
}

3.在vrrp_instance中新增监控的脚本

track_script {
	check_nginx_alive  # 追踪 nginx 脚本
}

4.重启Keepalived使得配置文件生效

systemctl restart keepalived

规则:以一个虚拟ip分组归为同一个路由
2 主节点配置:

global_defs {
	router_id keep_171
}
vrrp_instance VI_1 { 
	state MASTER
	interface ens33
	virtual_router_id 51
	priority 100
	advert_int 1
	authentication{
		auth_type PASS
		auth_pass 1111
	}
	virtual_ipaddress{
		192.168.1.161
	}
}

vrrp_instance VI_2 {
	state BACKUP 
	interface ens33
	virtual_router_id 52
	priority 80
	advert_int 1
	authentication {
		auth_type PASS
		auth_pass 1111
	}
	virtual_ipaddress{
		192.168.1.162
	}
}

备用节点配置

global_defs {
	router_id keep_172
}

vrrp_instance VI_1 {
	state BACKUP
	interface ens33
	virtual_router_id 51
	priority 80
	advert_int 1
	authentication {
		auth_type PASS
		auth_pass 1111
	}
	virtual_ipaddress {
		192.168.1.161
	}
}

vrrp_instance VI_2{
	state MASTER
	interface ens33
	virtual_router_id 52
	priority 100
	advert_int 1
	authentication {
		auth_type PASS
		auth_pass 1111
	}
	virtual_ipaddress {
		192.168.1.162
	}
}

别忘记分别重启两条Keepalived

#重启Keepalived
systemctl restart keepalived