准备工作

分别在主从上安装keepalived和nginx
yum install -y keepalived
yum install -y nginx
关闭主从上的防火墙和SELinux
systemctl stop firewalld
setenforce 0

配置主机

查看主机ip

[root@lynn-04 ~]# ifconfig
ens33: flags=4163<UP,BROADCAST,RUNNING,MULTICAST>  mtu 1500inet 192.168.130.116  netmask 255.255.255.0  broadcast 192.168.130.255inet6 fe80::181c:4847:3f62:dc4c  prefixlen 64  scopeid 0x20<link>ether 00:0c:29:60:ed:4a  txqueuelen 1000  (Ethernet)RX packets 11701  bytes 10394449 (9.9 MiB)RX errors 0  dropped 0  overruns 0  frame 0TX packets 13559  bytes 972155 (949.3 KiB)TX errors 0  dropped 0 overruns 0  carrier 0  collisions 0lo: flags=73<UP,LOOPBACK,RUNNING>  mtu 65536inet 127.0.0.1  netmask 255.0.0.0inet6 ::1  prefixlen 128  scopeid 0x10<host>loop  txqueuelen 1  (Local Loopback)RX packets 86  bytes 6720 (6.5 KiB)RX errors 0  dropped 0  overruns 0  frame 0TX packets 86  bytes 6720 (6.5 KiB)TX errors 0  dropped 0 overruns 0  carrier 0  collisions 0

清空主上keepalived配置文件/etc/keepalived/keepalived.conf

[root@lynn-04 ~]# > /etc/keepalived/keepalived.conf

编辑主上配置文件/etc/keepalived/keepalived.conf

[root@lynn-04 ~]# vim /etc/keepalived/keepalived.conf

加入以下内容：

global_defs {notification_email {aming@aminglinux.com}notification_email_from root@aminglinux.comsmtp_server 127.0.0.1smtp_connect_timeout 30router_id LVS_DEVEL
}
vrrp_script chk_nginx {script "/usr/local/sbin/check_ng.sh"interval 3
}
vrrp_instance VI_1 {state MASTERinterface ens33virtual_router_id 51priority 100advert_int 1authentication {auth_type PASSauth_pass aminglinux>com}virtual_ipaddress {192.168.130.100}track_script {chk_nginx}
}

定义主上监控脚本/usr/local/sbin/check_ng.sh

[root@lynn-04 ~]# vim /usr/local/sbin/check_ng.sh

写入下面内容

#!/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 startn2=`ps -C nginx --no-heading|wc -l`if [ $n2 -eq "0"  ]; thenecho "$d nginx down,keepalived will stop" >> /var/log/check_ng.logsystemctl stop keepalivedfi
fi

更改主上/usr/local/sbin/check_ng.sh权限

[root@lynn-04 ~]# chmod 755 /usr/local/sbin/check_ng.sh

启动主上keepalived

[root@lynn-04 ~]# systemctl start keepalived
[root@lynn-04 ~]# ps aux |grep keepalived
root       1741  0.0  0.1 120740  1404 ?        Ss   10:46   0:00 /usr/sbin/keepalived -D
root       1742  0.0  0.3 127476  3260 ?        S    10:46   0:00 /usr/sbin/keepalived -D
root       1745  0.0  0.3 131780  3116 ?        S    10:46   0:00 /usr/sbin/keepalived -D
root       1799  0.0  0.0 112676   988 pts/0    S+   10:47   0:00 grep --color=auto keepalived

为了区分主从的nginx需要把nginx的默认页做个标记

[root@lynn-04 ~]# echo master > /data/wwwroot/default/index.html

在另一台机器使用从ip访问
得到下面结果

[root@lynn-02 ~]# curl 192.168.130.116
master

配置从机

查看从机ip

[root@lynn-06 ~]# ifconfig
ens33: flags=4163<UP,BROADCAST,RUNNING,MULTICAST>  mtu 1500inet 192.168.130.128  netmask 255.255.255.0  broadcast 192.168.130.255inet6 fe80::fef6:fd37:2682:fabc  prefixlen 64  scopeid 0x20<link>ether 00:0c:29:af:03:e8  txqueuelen 1000  (Ethernet)RX packets 45666  bytes 48434560 (46.1 MiB)RX errors 0  dropped 0  overruns 0  frame 0TX packets 14753  bytes 1287938 (1.2 MiB)TX errors 0  dropped 0 overruns 0  carrier 0  collisions 0lo: flags=73<UP,LOOPBACK,RUNNING>  mtu 65536inet 127.0.0.1  netmask 255.0.0.0inet6 ::1  prefixlen 128  scopeid 0x10<host>loop  txqueuelen 1  (Local Loopback)RX packets 80  bytes 6256 (6.1 KiB)RX errors 0  dropped 0  overruns 0  frame 0TX packets 80  bytes 6256 (6.1 KiB)TX errors 0  dropped 0 overruns 0  carrier 0  collisions 0

清空从上配置文件/etc/keepalived/keepalived.conf

[root@lynn-06 ~]# > /etc/keepalived/keepalived.conf

编辑从上配置文件/etc/keepalived/keepalived.conf

[root@lynn-06 ~]# vim /etc/keepalived/keepalived.conf

加入下面内容

global_defs {notification_email {aming@aminglinux.com}notification_email_from root@aminglinux.comsmtp_server 127.0.0.1smtp_connect_timeout 30router_id LVS_DEVEL
}
vrrp_script chk_nginx {script "/usr/local/sbin/check_ng.sh"interval 3
}
vrrp_instance VI_1 {state BACKUPinterface ens33virtual_router_id 51priority 90advert_int 1authentication {auth_type PASSauth_pass aminglinux>com}virtual_ipaddress {192.168.130.100}track_script {chk_nginx}
}

定义从上监控脚本/usr/local/sbin/check_ng.sh

[root@lynn-06 ~]# vim /usr/local/sbin/check_ng.sh

加入下面内容

#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" ]; thensystemctl start nginxn2=`ps -C nginx --no-heading|wc -l`if [ $n2 -eq "0"  ]; thenecho "$d nginx down,keepalived will stop" >> /var/log/check_ng.logsystemctl stop keepalivedfi
fi

更改从上/usr/local/sbin/check_ng.sh权限

[root@lynn-06 ~]# chmod 755 /usr/local/sbin/check_ng.sh

启动从上keepalived

[root@lynn-06 ~]# systemctl start keepalived
[root@lynn-06 ~]# ps aux |grep keepalived
root       3589  0.0  0.1 120740  1400 ?        Ss   11:03   0:00 /usr/sbin/keepalived -D
root       3590  0.0  0.3 127476  3260 ?        S    11:03   0:00 /usr/sbin/keepalived -D
root       3591  0.0  0.3 131780  3124 ?        S    11:03   0:00 /usr/sbin/keepalived -D
root       3680  0.0  0.0 112676   988 pts/0    S+   11:03   0:00 grep --color=auto keepalived

为了区分主从的nginx需要把nginx的默认页做个标记

[root@lynn-06 ~]# echo backup > /usr/share/nginx/html/index.html

在另一台机器使用从ip访问
得到下面结果

[root@lynn-02 ~]# curl 192.168.130.128
backup

测试高可用

首先在主从keepalived都开启的情况下查看得到vip在主机上 使用另一台机器通过vip访问得到master

然后在主机keepalived关闭的情况下查看得到vip在从机上 使用另一台机器通过vip访问得到backup

再次开启主机的keepalived情况下查看得到vip又回到主机上 使用另一台机器通过vip访问得到master