Nginx + keepalived 双主解决方案
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工作原理：两台nginx通过Keepalived生成二个实例，二台Nginx的VIP互为备份，任何一台Nginx机器如果发生硬件损坏，Keepalived会自动将它的VIP地址切换到另一台机器，不影响客户端的访问。
IP 信息列表：
名称 IP
-----------------------------------
VIP1 192.168.200.254
VIP2 192.168.200.253
Nginx1 192.168.200.202
Nginx2 192.168.200.203
1、在Nginx1/2上编译安装nginx服务
首先搭建Nginx1，
[[email protected] ~]# yum -y install pcre-devel zlib-devel
[[email protected] ~]# useradd -M -s /sbin/nologin nginx
[[email protected] ~]# tar xf nginx-1.6.2.tar.gz -C /usr/src
[[email protected] ~]# cd /usr/src/nginx-1.6.2
[[email protected] nginx-1.6.2]# ./configure --prefix=/usr/local/nginx --user=nginx --group=nginx && make && make install
[[email protected] nginx-1.6.2]# cd /usr/local/nginx/html/
[[email protected] html]# echo "server 192.168.200.202" > index.html
[[email protected] html]# /usr/local/nginx/sbin/nginx
[[email protected] html]# netstat -anpt |grep nginx
tcp 0 0 0.0.0.0:80 0.0.0.0:* LISTEN 4503/nginx
搭建Nginx2， 同Nginx1搭建方式是一样的。
与Nginx1唯一不同的是：
[[email protected] html]# echo "server 192.168.200.203" > index.html
2、在Nginx1/2上编译安装keepalived服务
[[email protected] ~]# yum -y install kernel-devel openssl-devel
[[email protected] ~]# tar xf keepalived-1.2.13.tar.gz
[[email protected] ~]# cd keepalived-1.2.13
[[email protected] keepalived-1.2.13]# ./configure --prefix=/ --with-kernel-dir=/usr/src/kernels/2.6.18-194.el5-i686 && make && make install
[[email protected] ~]# chkconfig --add keepalived
[[email protected] ~]# chkconfig keepalived on
[[email protected] ~]# chkconfig --list keepalived
[roo[email protected] ~]# service keepalived start|stop
3、修改keepalived配置文件
[[email protected] ~]# vim /etc/keepalived/keepalived.conf
! Configuration File for keepalived
global_defs {
notification_email {
[email protected]
}
smtp_server 127.0.0.1
smtp_connect_timeout 30
router_id LVS_DEVEL
}
vrrp_instance VI_1 {
state BACKUP
interface eth0
virtual_router_id 51
priority 50
advert_int 1
authentication {
auth_type PASS
auth_pass 123
}
virtual_ipaddress {
192.168.200.254
}
}
vrrp_instance VI_2 {
state MASTER
interface eth0
virtual_router_id 52
priority 100
advert_int 1
authentication {
auth_type PASS
auth_pass 123
}
virtual_ipaddress {
192.168.200.253
}
}
==================================================================
[[email protected] ~]# vim /etc/keepalived/keepalived.conf
! Configuration File for keepalived
global_defs {
notification_email {
[email protected]
}
smtp_server 127.0.0.1
smtp_connect_timeout 30
router_id LVS_DEVEL
}
vrrp_instance VI_1 {
state MASTER
interface eth0
virtual_router_id 51
priority 100
advert_int 1
authentication {
auth_type PASS
auth_pass 123
}
virtual_ipaddress {
192.168.200.254
}
}
vrrp_instance VI_2 {
state BACKUP
interface eth0
virtual_router_id 52
priority 50
advert_int 1
authentication {
auth_type PASS
auth_pass 123
}
virtual_ipaddress {
192.168.200.253
}
}
[[email protected] ~]# service keepalived start
[[email protected] ~]# ip addr show dev eth0
2: eth0: <BROADCAST,MULTICAST,UP,LOWER_UP> mtu 1500 qdisc pfifo_fast state UP qlen 1000
link/ether 00:0c:29:2d:3d:97 brd ff:ff:ff:ff:ff:ff
inet 192.168.200.202/24 brd 192.168.200.255 scope global eth0
inet 192.168.200.254/32 scope global eth0
inet6 fe80::20c:29ff:fe2d:3d97/64 scope link
valid_lft forever preferred_lft forever
[[email protected] ~]# service keepalived start
[[email protected] ~]# ip addr show dev eth0
2: eth0: <BROADCAST,MULTICAST,UP,LOWER_UP> mtu 1500 qdisc pfifo_fast state UP qlen 1000
link/ether 00:0c:29:6f:7d:87 brd ff:ff:ff:ff:ff:ff
inet 192.168.200.203/24 brd 192.168.200.255 scope global eth0
inet 192.168.200.253/32 scope global eth0
inet6 fe80::20c:29ff:fe6f:7d87/64 scope link
valid_lft forever preferred_lft forever
[[email protected] ~]# elinks --dump http://192.168.200.254
server 192.168.200.202
[[email protected] ~]# elinks --dump http://192.168.200.253
server 192.168.200.203
Nginx-1/2 二台机器都执行监控Nginx进程的脚本
[[email protected] ~]# cat nginx_pidcheck
#!/bin/bash
while :
do
nginxpid=`ps -C nginx --no-header | wc -l`
if [ $nginxpid -eq 0 ]
then
/usr/local/nginx/sbin/nginx
sleep 5
nginxpid=`ps -C nginx --no-header | wc -l`
echo $nginxpid
if [ $nginxpid -eq 0 ]
then
/etc/init.d/keepalived stop
fi
fi
sleep 5
done
[[email protected] ~]# nohup sh nginx_pidcheck &
这是执行无限循环的脚本，两台Nginx机器上都有执行此脚本，每隔5秒执行一次，用ps -C是命令来收集nginx的PID值到底是否为0，如果是0的话，即Nginx已经进程死掉，尝试启动nginx进程；如果继续为0，即Nginx启动失败，则关闭本机的Keeplaived服务，VIP地址则会由备机接管，当然了，整个网站就会全部由备机的Nginx来提供服务了，这样保证Nginx服务的高可用。
脚本测试：
[[email protected] ~]# netstat -anpt |grep nginx
tcp 0 0 0.0.0.0:80 0.0.0.0:* LISTEN 4321/nginx
[[email protected] ~]# killall -s QUIT nginx
[[email protected] ~]# netstat -anpt |grep nginx
tcp 0 0 0.0.0.0:80 0.0.0.0:* LISTEN 59418/nginx
VIP转移测试：
[[email protected] ~]# ip addr show dev eth0
2: eth0: <BROADCAST,MULTICAST,UP,LOWER_UP> mtu 1500 qdisc pfifo_fast state UP qlen 1000
link/ether 00:0c:29:2d:3d:97 brd ff:ff:ff:ff:ff:ff
inet 192.168.200.202/24 brd 192.168.200.255 scope global eth0
inet 192.168.200.254/32 scope global eth0
inet6 fe80::20c:29ff:fe2d:3d97/64 scope link
valid_lft forever preferred_lft forever
[[email protected] ~]# service keepalived stop
停止 keepalived： [确定]
[[email protected] ~]# ip addr show dev eth0
2: eth0: <BROADCAST,MULTICAST,UP,LOWER_UP> mtu 1500 qdisc pfifo_fast state UP qlen 1000
link/ether 00:0c:29:2d:3d:97 brd ff:ff:ff:ff:ff:ff
inet 192.168.200.202/24 brd 192.168.200.255 scope global eth0
inet 192.168.200.254/32 scope global eth0
inet 192.168.200.253/32 scope global eth0
inet6 fe80::20c:29ff:fe2d:3d97/64 scope link
valid_lft forever preferred_lft forever
[[email protected] ~]# elinks --dump http://192.168.200.254
server 192.168.200.202
[[email protected] ~]# elinks --dump http://192.168.200.253
server 192.168.200.202
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