1.环境准备
服务器系统 角色 外网IP 内网IP
CentOS 7.5 keepalived-master eth0:10.0.0.5 eth1:172.16.1.5CentOS 7.5 keepalived-slave eth0:10.0.0.6 eth1:172.16.1.62.在lb01与lb02上分别安装keepalived[root@lb01 ~]# yum install keepalived -y
[root@lb02 ~]# yum install keepalived -y3.配置lb01, keepalived-master[root@lb01 ~]# cat /etc/keepalived/keepalived.conf
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 { 10.0.0.3/24 dev eth0 }}4.配置lb02, keepalived-backup[root@lb02 ~]# cat /etc/keepalived/keepalived.conf
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 { 10.0.0.3/24 dev eth0 }}5.对比keepalived的master与backup配置的区别Keepalived配置区别 Master配置 Backup节配置
route_id(唯一标识) route_id lb01 route_id lb02state(角色状态) state Master state Backuppriority(竞选优先级) priority 150 priority 1006.启动lb01与lb02的keepalived#lb01
[root@lb01 ~]# systemctl enable keepalived[root@lb01 ~]# systemctl start keepalived#lb02
[root@lb02 ~]# systemctl enable keepalived[root@lb02 ~]# systemctl start keepalived7.检查keepalived的虚拟IP地址是否漂移在lb01上进行如下操作
# lb01存在vip地址
[root@lb01 ~]# ip addr |grep 10.0.0.3 inet 10.0.0.3/24 scope global secondary eth0# 停止lb01上的keepalived, 检测vip已不存在
[root@lb01 ~]# systemctl stop keepalived[root@lb01 ~]# ip addr |grep 10.0.0.3在lb02上进行如下操作[root@lb02 ~]# ip addr|grep 10.0.0.3
inet 10.0.0.3/24 scope global secondary eth0lb01重新启动keepalived,发现地址被重新接管[root@lb01 ~]# systemctl start keepalived
[root@lb01 ~]# ip addr |grep 10.0.0.3 inet 10.0.0.3/24 scope global secondary eth03.Keepalived高可用配置 4.keepalived高可用列脑由于某些原因，导致两台keepalived高可用服务器在指定时间内，无法检测到对方的心跳消息，各自取得资源及服务的所有权，而此时的两台高可用服务器又都还活着。服务器网线松动等网络故障
服务器硬件故障发生损坏现象而崩溃主备都开启firewalld防火墙Nginx服务死掉等1.在备上编写检测脚本, 测试如果能ping通主并且备节点还有VIP的话则认为产生了列脑
[root@lb02 ~]# cat check_split_brain.sh
#!/bin/shlb01_vip=10.0.0.3lb01_ip=10.0.0.5while true;do ping -c 2 -W 3 $lb01_ip &>/dev/null if [ $? -eq 0 -a `ip add|grep "$lb01_vip"|wc -l` -eq 1 ];then echo "ha is split brain.warning." else echo "ha is ok" fisleep 5done2.如果Nginx宕机, 会导致用户请求失败, 但Keepalived并不会进行切换, 所以需要编写一个脚本检测Nginx的存活状态, 如果不存活则kill nginx和keepalived[root@lb01 ~]# mkdir /server/scripts
[root@lb01 ~]# vim /server/scripts/check_web.sh#!/bin/sh#使用while死循环while true;donginxpid=$(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Nginxif [ $nginxpid -eq 0 ];then systemctl start nginx sleep 1 #2.等待1秒后再次获取一次Nginx状态 nginxpid=$(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 exit 1 fifi sleep 2done[root@lb01 ~]# chmod +x /server/scripts/check_web.sh
在keepalived配置文件中调用此脚本，lb01与lb02都需操作[root@lb01 ~]# cat /etc/keepalived/keepalived.conf
global_defs { router_id LVS_01}# 每5秒执行一次脚本, 脚本执行内容不能超过5秒,否则会被中断再次重新运行脚本
vrrp_script check_web { script "/server/scripts/check_web.sh" interval 5 weight 50}vrrp_instance VI_1 {
state MASTER interface eth0 virtual_router_id 51 priority 150 advert_int 1 authentication { auth_type PASS auth_pass 1111 } virtual_ipaddress { 10.0.0.3/24 dev ens33 } track_script { check_web }}