作者：黄思悦-XHNZ_314 | 来源：互联网 | 2023-05-17 14:56
两台CentOS7，如下规划：192.168.202.128MASTER192.168.202.129BACKUP两台虚拟机准备，关闭防火墙，下载所需包，本次实验对象是给ng
两台CentOS7，如下规划：
192.168.202.128 MASTER
192.168.202.129 BACKUP
两台虚拟机准备，关闭防火墙，下载所需包，本次实验对象是给nginx使用高可用（keepalived）
# getenforce
Disabled //如若不是disabled
# setenforce 0 //先暂时关闭selinx
# yum install -y keepalived
# yum install -y nginx
安装nginx时报错，提示找不到该包，就修改下载源，就可以成功安装nginx
vi /etc/yum.repos.d/nginx.repo
# nginx.repo
[nginx]
name=nginx repo
baseurl=http://nginx.org/packages/centos/7/$basearch/
gpgcheck=0
enabled=1
修改master的keepalived配置文件
vi /etc/keepalived/keepalived.conf
global_defs {
notification_email {
aming@aminglinux.com
}
notification_email_from root@aminglinux.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 MASTER
interface eno16777736
virtual_router_id 51
priority 100
advert_int 1
authentication {
auth_type PASS
auth_pass aminglinux>com
}
virtual_ipaddress {
192.168.202.100
}
track_script {
chk_nginx
}
}
修改master脚本
# 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
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
修改master脚本权限
# chmod 755 /usr/local/sbin/check_ng.sh
启动master的keepalived
# systemctl start keepalived
修改backup的keepalived配置文件
# vi /etc/keepalived/keepalived.conf
global_defs {
notification_email {
aming@aminglinux.com
}
notification_email_from root@aminglinux.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 eno16777736
virtual_router_id 51
priority 90
advert_int 1
authentication {
auth_type PASS
auth_pass aminglinux>com
}
virtual_ipaddress {
192.168.202.100
}
track_script {
chk_nginx
}
}
修改backup脚本
# 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
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
修改backup脚本权限
# chmod 755 /usr/local/sbin/check_ng.sh
启动backup的keepalived
# systemctl start keepalived
测试1：通过curl ip查看状态
[root@202-128 ~]# curl 192.168.202.128
Master
[root@202-128 ~]# curl 192.168.202.129
Backup
[root@202-128 ~]# curl 192.168.202.100
Master
这里显示结果Master、Backup，修改yum安装的nginx的默认index文件，
# vi /usr/share/nginx/html/index.html
Master
测试2：关闭master上的nginx，结果显示nginx依然会启动是因为配置文件 /usr/local/sbin/check_ng.sh的脚本
[root@202-128 ~]# systemctl stop nginx
[root@202-128 ~]# ps aux |grep nginx
root 12703 0.0 0.0 48532 976 ? Ss 22:25 0:00 nginx: master process /usr/sbin/nginx -c /etc/nginx/nginx.conf
nginx 12704 0.0 0.1 48932 1928 ? S 22:25 0:00 nginx: worker process
root 12709 0.0 0.0 112644 948 pts/0 R+ 22:25 0:00 grep --color=auto nginx
测试3：关闭master上的keepalived、nginx，显示backup起作用
[root@202-128 ~]# systemctl stop keepalived
[root@202-128 ~]# systemctl stop nginx
[root@202-128 ~]# curl 192.168.202.128
curl: (7) Failed connect to 192.168.202.128:80; Connection refused
[root@202-128 ~]# curl 192.168.202.129
Backup
[root@202-128 ~]# curl 192.168.202.100
Backup
测试4：开启master的keepalived，master重新起作用，backup作冗余。
[root@202-128 ~]# systemctl start keepalived
[root@202-128 ~]# curl 192.168.202.128
Master
[root@202-128 ~]# curl 192.168.202.129
Backup
[root@202-128 ~]# curl 192.168.202.100
Master
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