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
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3、两台设备均安装nginx
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yum
install
-y nginx
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主设备配置
1、编辑keepalived配置文件
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[root@juispan ~]
# > /etc/keepalived/keepalived.conf
[root@juispan ~]
# 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
}
}
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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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[root@juispan ~]
# 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
[root@juispan ~]
# chmod 755 /usr/local/sbin/check_ng.sh
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3、启动服务
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[root@juispan ~]
# systemctl start keepalived
[root@juispan ~]
# ps aux | grep keep
root 2416 0.0 0.1 111708 1316 ? Ss 19:29 0:00
/usr/sbin/keepalived
-D
root 2417 0.0 0.2 111708 2560 ? S 19:29 0:00
/usr/sbin/keepalived
-D
root 2418 0.0 0.1 111708 1616 ? S 19:29 0:00
/usr/sbin/keepalived
-D
root 2479 0.0 0.0 112664 976 pts
/0
S+ 19:29 0:00
grep
--color=auto keep
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4、清空策略并验证
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[root@juispan ~]
# systemctl stop firewalld
[root@juispan ~]
# systemctl disable firewalld
Removed
symlink
/etc/systemd/system/basic
.target.wants
/firewalld
.service.
Removed
symlink
/etc/systemd/system/dbus-org
.fedoraproject.FirewallD1.service.
[root@juispan ~]
# setenforce 0
[root@juispan ~]
# less /var/log/messages ##查看日志
[root@juispan ~]
# 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
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从设备配置
1、关闭防火墙
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[root@localhost ~]
# systemctl stop firewalld
[root@localhost ~]
# systemctl disable firewalld
Removed
symlink
/etc/systemd/system/dbus-org
.fedoraproject.FirewallD1.service.
Removed
symlink
/etc/systemd/system/basic
.target.wants
/firewalld
.service.
[root@localhost ~]
# setenforce 0
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2、配置keepalived文件
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[root@localhost ~]
# > /etc/keepalived/keepalived.conf
[root@localhost ~]
# 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
}
}
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3、编写启动脚本
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[root@localhost ~]
# 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
[root@localhost ~]
# chmod 755 /usr/local/sbin/check_ng.sh
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4、启动服务
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[root@localhost ~]
# systemctl start keepalived
[root@localhost ~]
# ps aux | grep keepalived
root 3266 0.0 0.1 111708 1308 ? Ss 21:30 0:00
/usr/sbin/keepalived
-D
root 3267 0.0 0.2 111708 2548 ? S 21:30 0:00
/usr/sbin/keepalived
-D
root 3268 0.1 0.1 111708 1620 ? S 21:30 0:00
/usr/sbin/keepalived
-D
root 3321 0.0 0.0 112664 976 pts
/1
S+ 21:30 0:00
grep
--color=auto keepalived
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测试高可用
1、编辑nginx主页
|
1
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[root@juispan ~]
# echo "this is master" > /usr/share/nginx/html/index.html
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[root@localhost ~]
# echo "this is backup" > /usr/share/nginx/html/index.html
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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。
本文转自Grodd51CTO博客，原文链接：http://blog.51cto.com/juispan/1964009，如需转载请自行联系原作者
