keepalived高可用
1、keepalived
通过vrrp协议实现的高可用. 虚拟路由冗余协议
VMAC和VIP实现高可用技术方案 地址漂移
2、keepalived安装
[root@lb01 ~]# yum install keepalived -y [root@lb02 ~]# yum install keepalived -y
3、keeplaived配置
主的配置文件
global_defs {
router_id lb01
}
vrrp_instance VI_1 {
state MASTER
interface eth0
virtual_router_id 50
priority 150
advert_int 1
authentication {
auth_type PASS
auth_pass 1111
}
virtual_ipaddress {
10.0.0.3
}
}备的配置文件
global_defs {
router_id lb02
}
vrrp_instance VI_1 {
state BACKUP
interface eth0
virtual_router_id 50
priority 100
advert_int 1
authentication {
auth_type PASS
auth_pass 1111
}
virtual_ipaddress {
10.0.0.3
}
}3、keepalived启动
[root@lb01 ~]# systemctl start keepalived [root@lb01 ~]# systemctl enable keepalived
4、主配置文件和备配置文件区别
Keepalived配置区别 Master配置 Backup节配置
route_id(唯一标识) lb01 lb02
state(角色状态) MASTER BACKUP
priority(优先级) 150 100
keepalived检测脑裂
vip=10.0.0.3
master_ip=10.0.0.5
while true;do
#1.通过ping命令测试主是否是通
ping -c 2 -W 3 $master_ip &>/dev/null
#2.ping的通master的ip,同时本地还存在一个vip地址
if [ $? -eq 0 -a `ip add|grep "$vip"|wc -l` -eq 1 ];then echo "ha is split brain.warning." else echo "ha is ok" fi sleep 5 done-------------------------------------------------------------
[root@lb02 scripts]# cat check_split.sh vip=10.0.0.3 master_ip=10.0.0.5 while true;do ping -c 2 -W 3 $master_ip &>/dev/null if [ $? -eq 0 -a `ip add|grep "$vip"|wc -l` -eq 1 ];then echo "ha is split brain.warning." pkill keepalived &>/dev/null if [ $? -eq 0 ];then echo "Keepalived pkill" else exit fi else echo "ha is ok" fi sleep 5 done
如果Nginx故障了,怎么办?
1.尝试拉起nginx
2.如果拉不起Nginx,则把keepalived给杀死
[root@lb01 ~]# cat /scripts/check_web.sh #!/bin/sh nginxpid=$(ps -C nginx --no-header|wc -l) #1.判断Nginx是否存活,如果不存活则尝试启动Nginx if [ $nginxpid -eq 0 ];then systemctl start nginx sleep 3 #2.等待3秒后再次获取一次Nginx状态 nginxpid=$(ps -C nginx --no-header|wc -l) #3.再次进行判断, 如Nginx还不存活则停止Keepalived,让地址进行漂移,并退出脚本 if [ $nginxpid -eq 0 ];then systemctl stop keepalived fi fi
-----------------配置keepalived支持脚本
1.给脚本增加执行权限
[root@lb01 conf.d]# chmod +x /scripts/check_web.sh
2.修改keepalived配置文件
[root@lb01 conf.d]# cat /etc/keepalived/keepalived.conf
global_defs {
router_id lb01
}
#定义脚本存放的位置
vrrp_script check_web {
script "/scripts/check_web.sh"
interval 5
}
vrrp_instance VI_1 {
state BACKUP
priority 150
nopreempt
interface eth0
virtual_router_id 50
advert_int 1
authentication {
auth_type PASS
auth_pass 1111
}
virtual_ipaddress {
10.0.0.3
}
#调用并运行该脚本
track_script {
check_web
}
}
