9.7 KiB
keepalived高可用集群
keepalived介绍
keepalived是集群管理中保证集群高可用的一个服务软件，其功能类似于heartbeat，用来防止单点故障。
脑裂问题：
backup vip
master vip
解决：stonith shoot the other node in the head 爆头
重启keepalived 关闭keepalived服务
keepalived工作原理
keepalived是以**VRRP**协议为实现基础的，是实现路由器高可用的协议，VRRP全称Virtual Router Redundancy Protocol，即**虚拟路由冗余协议。**
面试题(keepalived的工作原理) 将N台提供相同功能的服务器组成一个服务器组，这个组里面有一个master和多个backup，master上面有一个对外提供服务的vip（该服务器所在局域网内其他机器的默认路由为该vip），master会发组播，当backup收不到vrrp包时就认为master宕掉了，这时就需要根据VRRP的优先级来选举一个backup当master
keepalived主要有三个模块，分别是core、check和vrrp。core模块为keepalived的核心，负责主进程的启动、维护以及全局配置文件的加载和解析。check负责健康检查，包括常见的各种检查方式。vrrp模块是来实现VRRP协议的。
keepalived部署
++++++++++++
+---------------------------> + Client + 192.168.122.1/24 (真实机做客户端)
| ++++++++++++
| ________________|________________ VIP eth0:1 192.168.122.254/24
| | |
| ++++++++++++++++ +++++++++++++++++
| + Director master + + Director backup +
| ++++++++++++++++ +++++++++++++++++
| DIP eth0 192.168.122.10/24 DIP eth0 192.168.122.20/24
| |____________________________________________________________|
|___________________________________________________________________ ____________________ _________|__________________________________________________
| |
| |
++++++++++++++++ ++++++++++++++++
\+ Real Server A + + Real Server B +
++++++++++++++++ ++++++++++++++++
eth0 192.168.122.30/24 eth0 192.168.122.40/24
分别在Director master、Director backup 上部署浮动资源（VIP IPVS策略） 测试2个Director在DR模式下都工作正常。测试完成后都撤掉浮动资源。
web上操作
web01 web02 添加同一网段虚拟网卡 且都是同一网段的
lvs上操作
在两台dr配置keepalivied (lvs上)
1. 在master上安装配置Keepalived
# yum install keepalived -y
2. 修改配置文件(清空原有配置文件)
# cd /etc/keepalived/
# vim keepalived.conf
//全局配置 ! Configuration File for keepalived global_defs { notification_email { root@localhost } notification_email_from keepalived@localhost smtp_server 127.0.0.1 smtp_connect_timeout 30 router_id Director1 //两边是一样的 } //局部配置 vrrp_instance VI_1 { state MASTER //另外一台机器是BACKUP interface eth0 //心跳网卡 DIP那一块网卡 virtual_router_id 51 priority 50 //优先级 advert_int 1 //检查间隔，单位秒 authentication { auth_type PASS auth_pass 1111 } virtual_ipaddress { 192.168.122.254/24 dev eth0 //VIP随便自己定义(和web的是一个虚拟IP) 只要是同一个网段就可以 } }
virtual_server 192.168.122.254 80 { //LVS 配置，VIP(和web的一个ip)上面是啥这块就是 ^ delay_loop 3 //服务论询的时间间隔 lb_algo rr //LVS 调度算法 lb_kind DR // LVS 集群模式 protocol TCP real_server 192.168.122.30 80 { weight 1 TCP_CHECK { connect_timeout 3 } } real_server 192.168.122.40 80 { weight 1 TCP_CHECK { connect_timeout 3 } } }
3.在backup上安装keepalived
# yum install keepalived -y
4.拷贝master上的keepalived.conf到backup上：
# scp keepalived.conf 192.168.122.20:/etc/keepalived/
5.拷贝后,修改配置文件 state BACKUP priority 100
6.两个Director上启动服务
# systemctl start keepalived
7.测试 7.测试 1）观察lvs路由条目 2）观察vip地址在哪台机器上（有可能两台机器上都有，但是他好用没有问题即可） 3）客户端浏览器访问vip 4）关闭master上的keepalived服务，再次访问vip
扩展实验-keepalived+mysql
mysql可以是以下3种情况
1、双主
2、mysql-cluster
3、gelara集群
项目环境 VIP 192.168.122.100 mysql1 192.168.122.10 mysql2 192.168.122.20 vip 主(keepalived) 主(keepalived）
实现过程概要
一、mysql 主主同步 二、在两台mysql上安装keepalived 三、keepalived 主备配置文件 四、mysql状态检测脚本/root/bin/keepalived_check_mysql.sh 五、测试及诊断 注 keepalived之间使用vrrp组播方式通信使用的IP地址是224.0.0.18 ＝＝＝＝＝＝＝＝＝＝＝＝＝＝＝＝＝＝＝＝＝＝＝＝＝＝＝＝＝＝＝＝＝＝＝＝＝＝ 实施步骤 一、mysql 主主同步 <略>
二、安装keepalived
两台
# yum install keepalived -y
三、keepalived 主备配置文件 主备置文件不同处有 state priority
192.168.122.10 Master配置
# vim /etc/keepalived/keepalived.conf
! Configuration File for keepalived
global_defs { router_id mysql1 //两边一样 }
vrrp_script check_run { //定义配置健康检查脚本的配置名称check_run script "/root/keepalived_check_mysql.sh" interval 5 //执行健康检查的时间间隔 单位s }
vrrp_instance VI_1 { state MASTER interface eth0 virtual_router_id 88 priority 100 advert_int 1 //检查keepalived本身服务的时间间隔 authentication { auth_type PASS auth_pass 1111 }
track_script {
**check_run** //名字必须和上面的脚本配置名称一致
}
virtual_ipaddress {
**192.168.122.100** dev **eth0**
}
}
192.168.122.20 Slave配置
# vim /etc/keepalived/keepalived.conf
! Configuration File for keepalived
global_defs { router_id mysql1 }
vrrp_script check_run { script "/root/keepalived_check_mysql.sh" interval 5 }
vrrp_instance VI_1 { state BACKUP interface eth0 virtual_router_id 88 priority 90 advert_int 1 authentication { auth_type PASS auth_pass 1111 }
track_script {
check_run
}
virtual_ipaddress {
**192.168.122.100**
}
}
四、mysql状态检测脚本
/root/keepalived_check_mysql.sh（两台MySQL同样的脚本）
版本一：简单使用： #!/bin/bash /usr/bin/mysql -h ip -uroot -p123 -e "show status;" &>/dev/null if [ $? -ne 0 ] ;then systemctl stop keepalived fi
#此处的ip是本地ip
版本二：检查多次
vim /root/keepalived_check_mysql.sh
#!/bin/bash MYSQL=/usr/local/mysql/bin/mysql MYSQL_HOST=localhost MYSQL_USER=root MYSQL_PASSWORD=1111 CHECK_TIME=3
#mysql is working MYSQL_OK is 1 , mysql down MYSQL_OK is 0 MYSQL_OK=1
check_mysql_helth (){ $MYSQL -h $MYSQL_HOST -u $MYSQL_USER -p${MYSQL_PASSWORD} -e "show status;" &>/dev/null if [ $? -eq 0 ] ;then MYSQL_OK=1 else MYSQL_OK=0 fi return $MYSQL_OK }
while [ $CHECK_TIME -ne 0 ] do check_mysql_helth if [ $MYSQL_OK -eq 1 ] ; then exit 0 fi
if [ $MYSQL_OK -eq 0 ] && [ $CHECK_TIME -eq 1 ];then
/etc/init.d/keepalived stop
exit 1
fi
let CHECK_TIME--
sleep 1
done
版本三：检查多次
vim /root/keepalived_check_mysql.sh
#!/bin/bash MYSQL=/usr/local/mysql/bin/mysql MYSQL_HOST=localhost MYSQL_USER=root MYSQL_PASSWORD=1111 CHECK_TIME=3
#mysql is working MYSQL_OK is 1 , mysql down MYSQL_OK is 0 MYSQL_OK=1
check_mysql_helth (){ $MYSQL -h $MYSQL_HOST -u $MYSQL_USER -p${MYSQL_PASSWORD} -e "show status;" &>/dev/null if [ $? -eq 0 ] ;then MYSQL_OK=1 else MYSQL_OK=0 fi return $MYSQL_OK }
while [ $CHECK_TIME -ne 0 ] do check_mysql_helth if [ $MYSQL_OK -eq 1 ] ; then exit 0 fi
let CHECK_TIME--
sleep 1
done /etc/init.d/keepalived stop exit 1
chmod 755 /root/keepalived_check_mysql.sh
两边均启动keepalived
日志查看脚本是否被执行
tail -f /var/log/messages
Jun 19 15:20:19 xen1 Keepalived_vrrp[6341]: Using LinkWatch kernel netlink reflector... Jun 19 15:20:19 xen1 Keepalived_vrrp[6341]: VRRP sockpool: [ifindex(2), proto(112), fd(11,12)] Jun 19 15:20:19 xen1 Keepalived_vrrp[6341]: VRRP_Script(check_run) succeeded