keepalived配置高可用集群
准备工作1、设备分配192.168.137.100 master
192.168.137.150 backup
192.168.137.254 vip
2、两台设备均安装keepalived
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yum install -y keepalived
3、两台设备均安装nginx
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yum install -y nginx
主设备配置
1、编辑keepalived配置文件
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# > /etc/keepalived/keepalived.conf
# vi /etc/keepalived/keepalived.conf
global_defs {
notification_email { ##出现问题后接收提示的邮箱
test@test.com
}
notification_email_from root@test2.com##发件人
smtp_server 127.0.0.1 ##邮件服务器
smtp_connect_timeout 30 ##延时
router_id LVS_DEVEL
}
vrrp_script chk_nginx { ##检查服务状态
script "/usr/local/sbin/check_ng.sh"
interval 3
}
vrrp_instance VI_1 { ##定义master相关配置
state MASTER ##设定角色
interface ens33 ##指定发送vrrp包的网卡
virtual_router_id 51 ##定义VRRP RID，要和从设备一致
priority 100 ##优先级，越大越优
advert_int 1
authentication {
auth_type PASS ##定义认证类型
auth_pass 123456 ##认证口令
}
virtual_ipaddress { ##VIP
192.168.137.254
}
track_script {
chk_nginx ##加载定义的chk_nginx脚本
}
}
2、编辑监控脚本
如果进程里面没发现nginx那就代表着服务宕机了，然后脚本自动的再次启动nginx服务。 如果服务还是不可以启动，就把启动报错日志输入到指定的位置，然后为防止“脑裂”就把keepalived也关闭。
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# vi /usr/local/sbin/check_ng.sh
#!/bin/bash
#时间变量，用于记录日志
d=`date --date today +%Y%m%d_%H:%M:%S`
#计算nginx进程数量
n=`ps -C nginx --no-heading|wc -l`
#如果进程为0，则启动nginx，并且再次检测nginx进程数量，
#如果还为0，说明nginx无法启动，此时需要关闭keepalived
if [ $n -eq "0" ]; then
/etc/init.d/nginx start
n2=`ps -C nginx --no-heading|wc -l`
if [ $n2 -eq "0"]; then
echo "$d nginx down,keepalived will stop" >> /var/log/check_ng.log
systemctl stop keepalived
fi
fi
# chmod 755 /usr/local/sbin/check_ng.sh
3、启动服务
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# systemctl startkeepalived
# ps aux | grep keep
root 24160.00.1 1117081316 ? Ss 19:29 0:00 /usr/sbin/keepalived -D
root 24170.00.2 1117082560 ? S 19:29 0:00 /usr/sbin/keepalived -D
root 24180.00.1 1117081616 ? S 19:29 0:00 /usr/sbin/keepalived -D
root 24790.00.0 112664 976 pts/0 S+ 19:29 0:00 grep --color=auto keep
4、清空策略并验证
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# systemctl stop firewalld
# systemctl disable firewalld
Removed symlink /etc/systemd/system/basic.target.wants/firewalld.service.
Removed symlink /etc/systemd/system/dbus-org.fedoraproject.FirewallD1.service.
# setenforce 0
# less /var/log/messages ##查看日志
# ip addr
2: ens33: <BROADCAST,MULTICAST,UP,LOWER_UP> mtu 1500 qdisc pfifo_fast state UP qlen 1000
link/ether 00:0c:29:0c:4d:a8 brd ff:ff:ff:ff:ff:ff
inet 192.168.137.100/24 brd 192.168.137.255 scope global ens33
valid_lft forever preferred_lft forever
inet 192.168.137.254/32 scope global ens33 ##已加载VIP
valid_lft forever preferred_lft forever
从设备配置
1、关闭防火墙
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# systemctl stop firewalld
# systemctl disable firewalld
Removed symlink /etc/systemd/system/dbus-org.fedoraproject.FirewallD1.service.
Removed symlink /etc/systemd/system/basic.target.wants/firewalld.service.
# setenforce 0
2、配置keepalived文件
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# > /etc/keepalived/keepalived.conf
# vi /etc/keepalived/keepalived.conf
global_defs {
notification_email {
test@test.com
}
notification_email_from root@test.com
smtp_server 127.0.0.1
smtp_connect_timeout 30
router_id LVS_DEVEL
}
vrrp_script chk_nginx {
script "/usr/local/sbin/check_ng.sh"
interval 3
}
vrrp_instance VI_1 {
state BACKUP
interface ens33
virtual_router_id 51
priority 90
advert_int 1
authentication {
auth_type PASS
auth_pass 123456
}
virtual_ipaddress {
192.168.137.254
}
track_script {
chk_nginx
}
}
3、编写启动脚本
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# vi /usr/local/sbin/check_ng.sh
#时间变量，用于记录日志
d=`date --date today +%Y%m%d_%H:%M:%S`
#计算nginx进程数量
n=`ps -C nginx --no-heading|wc -l`
#如果进程为0，则启动nginx，并且再次检测nginx进程数量，
#如果还为0，说明nginx无法启动，此时需要关闭keepalived
if [ $n -eq "0" ]; then
systemctl start nginx
n2=`ps -C nginx --no-heading|wc -l`
if [ $n2 -eq "0"]; then
echo "$d nginx down,keepalived will stop" >> /var/log/check_ng.log
systemctl stop keepalived
fi
fi
# chmod 755 /usr/local/sbin/check_ng.sh
4、启动服务
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# systemctl start keepalived
# ps aux | grep keepalived
root 32660.00.1 1117081308 ? Ss 21:30 0:00 /usr/sbin/keepalived -D
root 32670.00.2 1117082548 ? S 21:30 0:00 /usr/sbin/keepalived -D
root 32680.10.1 1117081620 ? S 21:30 0:00 /usr/sbin/keepalived -D
root 33210.00.0 112664 976 pts/1 S+ 21:30 0:00 grep --color=auto keepalived
测试高可用
1、编辑nginx主页
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# echo "this is master" > /usr/share/nginx/html/index.html
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# echo "this is backup" > /usr/share/nginx/html/index.html
2、客户端测试
3、主设备模拟宕机，关闭keepalived服务除了配置nginx的高可用，也可以配置其他服务的高可用，比如mysql的高可用，但前提是一定要保证双方的数据是一致的。如果主mysql宕机，从mysql的数据一定会和主设备不一致。
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