KEEPALIVED安装与使用 - 负载均衡

#官网
	https://www.keepalived.org/download.html

#安装
###源码安装
	#安装依赖
	yum -y install openssl openssl-devel
	
	#下载安装
	wget https://www.keepalived.org/software/keepalived-2.2.4.tar.gz
	tar -zxvf keepalived-2.2.4.tar.gz
	mv keepalived-2.2.4 /usr/local/keepalived
	cd /usr/local/keepalived
	./configure --sysconf=/etc
	make
	make install

###yum安装

yum -y install keepalived

---

###启动与停止

systemctl start keepalived.service
	systemctl status keepalived.service

###修改主配置

vim /etc/keepalived/keepalived.conf

! Configuration File for keepalived
	global_defs {
	   notification_email {
			wja84281865@163.com
			wutianhao@163.com
			#当服务器出现故障进行主从切换时会发邮件给这列表中的人
	   }
	   notification_email_from root@localhost	#邮件发送者
	   smtp_server 192.168.31.88	#邮件服务器IP地址
	   smtp_connect_timeout 30		#连接超时时间
	   router_id MySQL1				#设备标识
	   vrrp_skip_check_adv_addr
	   vrrp_garp_interval 0
	   vrrp_gna_interval 0
	}
	
	vrrp_script check_nginx {	#监控脚本
	        script "/etc/keepalived/nginx_check.sh"
	        interval 2
	}
	
	vrrp_instance VI_1 {
	    state BACKUP              #角色
	    interface ens33           #绑定网卡
	    virtual_router_id 60	  #主从此配置一定要相同
	    priority 100              #优先级，越高为主
	    advert_int 1
	    nopreempt                 #非抢占模式
	    authentication {
	        auth_type PASS
	        auth_pass 1qaz@WSX
	    }
	   track_script {
	        check_nginx 		 #监控脚本
	}
	    virtual_ipaddress {
	       192.168.31.240		#浮动IP
	    }
	}
	
####主脚本

vim /etc/keepalived/nginx_check.sh
	
	#!/bin/bash
	
	Ng=`ps -C nginx --no-header | wc -l`
	if [ $Ng -eq 0 ];then
		NG_STATUS=1
	else
		NG_STATUS=0
	fi
	exit $NG_STATUS

###修改从配置

vim /etc/keepalived/keepalived.conf

! Configuration File for keepalived
	global_defs {
	   notification_email {
			wja84281865@163.com
			wutianhao@163.com
			#当服务器出现故障进行主从切换时会发邮件给这列表中的人
	   }
	   notification_email_from root@localhost	#邮件发送者
	   smtp_server 192.168.31.88	#邮件服务器IP地址
	   smtp_connect_timeout 30		#连接超时时间
	   router_id MySQL2				#设备标识
	   vrrp_skip_check_adv_addr
	   vrrp_garp_interval 0
	   vrrp_gna_interval 0
	}
	
	vrrp_script check_nginx {	#监控脚本
	        script "/etc/keepalived/nginx_check.sh"
	        interval 2
	}
	
	vrrp_instance VI_1 {
	    state BACKUP              #角色
	    interface ens33           #绑定网卡
	    virtual_router_id 60	  #主从此配置一定要相同
	    priority 90               #优先级，越高为主
	    advert_int 1
	    nopreempt                 #非抢占模式
	    authentication {
	        auth_type PASS
	        auth_pass 1qaz@WSX
	    }
	   track_script {
	        check_nginx           #监控脚本
	}
	    virtual_ipaddress {
	       192.168.31.240		 #浮动IP
	    }
	}

####从脚本

vim /etc/keepalived/mysql_down.sh
	
	#!/bin/bash
	Ng=`ps -C nginx --no-header | wc -l`
	if [ $Ng -eq 0 ];then
		NG_STATUS=1
	else
		NG_STATUS=0
	fi
	exit $NG_STATUS
	
	
###keepalived配置，解决vip无法ping通，虚拟服务器端口无法访问的问题
keepalived.conf中vip配置好后，通过ip addr可以看到vip已经顺利挂载，但是无法ping通，并且防火墙都已关闭，**原因是keepalived.conf配置中默认vrrp_strict打开了，需要把它注释掉。重启keepalived即可ping通。**

---
###keepalived防火墙配置
####Keepalived使用vrrp组播，默认地址是224.0.0.18，因此要配置防火墙放过。
	iptables -I INPUT -i eth0 -d 224.0.0.0/8 -p vrrp -j ACCEPT
	iptables -I OUTPUT -o eth0 -d 224.0.0.0/8 -p vrrp -j ACCEPT

---