CenOS5 x86下配置Nginx+keepalived主从负载均衡
CenOS5.8x86下配置Nginx+keepalived主从负载均衡
一、环境：
centos5.8x86_64、nginx-0.8.46、keepalived-1.1.19
主nginx负载均衡器：192.168.1.122
辅nginx负载均衡器：192.168.1.123
vip：192.168.1.128
两台Apache Web服务器
二、安装keepalived
cd/usr/local/src
wget http://www.keepalived.org/software/keepalived-1.1.19.tar.gz
tar zxvfkeepalived-1.1.19.tar.gz
cdkeepalived-1.1.19
./configure--prefix=/usr/local/keepalived
make
makeinstall
以下三行是为了将keepalived做成服务启动方式，方便管理
cp /usr/local/keepalived/sbin/keepalived/usr/sbin/
cp/usr/local/keepalived/etc/sysconfig/keepalived /etc/sysconfig/
cp/usr/local/keepalived/etc/rc.d/init.d/keepalived /etc/init.d/
mkdir/etc/keepalived
上面的安装过程可以写一个脚本，名字为install_keepalived.sh,内容如下所示：
#!/bin/bash
cd/usr/local/src
wget http://www.keepalived.org/software/keepalived-1.1.19.tar.gz
tar zxvfkeepalived-1.1.19.tar.gz
cdkeepalived-1.1.19
./configure--prefix=/usr/local/keepalived
make
makeinstall
cp/usr/local/keepalived/sbin/keepalived /usr/sbin/
cp/usr/local/keepalived/etc/sysconfig/keepalived /etc/sysconfig/
cp/usr/local/keepalived/etc/rc.d/init.d/keepalived /etc/init.d/
给其执行权限即可执行了,chmod +x install_keepalived.sh。
mkdir/etc/keepalived
cd/etc/keepalived/
vimkeepalived.conf
!Configuration File for keepalived
global_defs{
notification_email {
}
smtp_server 127.0.0.1
smtp_connect_timeout 30
router_id LVS_DEVEL
}
vrrp_instanceVI_1 {
state MASTER
interface eth0
virtual_router_id 51
mcast_src_ip 192.168.1.122 <==主nginx的IP地址
priority 101
advert_int 1
authentication {
auth_type PASS
auth_pass chtopnet
}
virtual_ipaddress {
192.168.1.128 <==vip地址
}
}
servicekeepalived start
[root@localhostkeepalived]# ip addr
1: lo:<LOOPBACK,UP,LOWER_UP> mtu 16436 qdisc noqueue
link/loopback 00:00:00:00:00:00 brd00:00:00:00:00:00
inet 127.0.0.1/8 scope host lo
inet6 ::1/128 scope host
valid_lft forever preferred_lft forever
2: eth0:<BROADCAST,MULTICAST,UP,LOWER_UP> mtu 1500 qdisc pfifo_fast qlen 1000
link/ether 00:0c:29:61:b5:f0 brdff:ff:ff:ff:ff:ff
inet 192.168.1.122/24 brd 192.168.1.255scope global eth0
inet192.168.1.128/32 scope global eth0
inet6 fe80::20c:29ff:fe61:b5f0/64 scopelink
valid_lft forever preferred_lft forever
3: sit0:<NOARP> mtu 1480 qdisc noop
link/sit 0.0.0.0 brd 0.0.0.0
4:virbr0: <BROADCAST,MULTICAST,UP,LOWER_UP> mtu 1500 qdisc noqueue
link/ether 00:00:00:00:00:00 brdff:ff:ff:ff:ff:ff
inet 192.168.122.1/24 brd 192.168.122.255scope global virbr0
说明主机上面的VIP地址已经启动，这样主服务器就配置好了，辅机的配置大致一样，除了配置文件有少部分的变化，下面贴出辅机的配置文件：
!Configuration File for keepalived
global_defs{
notification_email {
}
smtp_server 127.0.0.1
smtp_connect_timeout 30
router_id LVS_DEVEL
}
vrrp_instanceVI_1 {
state BACKUP
interface eth0
virtual_router_id 51
mcast_src_ip 192.168.1.123 <==主nginx的IP的地址
priority 100
advert_int 1
authentication {
auth_type PASS
auth_pass chtopnet
}
virtual_ipaddress {
192.168.1.128
}
}
检查其配置
[root@localhostkeepalived]# ip addr
1: lo:<LOOPBACK,UP,LOWER_UP> mtu 16436 qdisc noqueue
link/loopback 00:00:00:00:00:00 brd00:00:00:00:00:00
inet 127.0.0.1/8 scope host lo
inet6 ::1/128 scope host
valid_lft forever preferred_lft forever
2: eth0:<BROADCAST,MULTICAST,UP,LOWER_UP> mtu 1500 qdisc pfifo_fast qlen 1000
link/ether 00:0c:29:3b:8f:cc brdff:ff:ff:ff:ff:ff
inet 192.168.1.123/24 brd 192.168.1.255scope global eth0
inet6 fe80::20c:29ff:fe3b:8fcc/64 scopelink
valid_lft forever preferred_lft forever
3: sit0:<NOARP> mtu 1480 qdisc noop
link/sit 0.0.0.0 brd 0.0.0.0
测试其效果方法很简单，分别在两台Web的上/var/www/html/下建立不同的主页及内容文
件index.html，然后通过负载均衡机器测试即可。
实验推荐步骤：
一、在主从Nginx机器上面分别配置好nginx的upstream模块，在XP客户端机器上面可以分别访问两台LB机器，均能使其达到负载均衡的目的；
二、分别停用或重启Nginx机器，然后在XP客户端访问VIP地址，看服务是否停止；多用ip addr看VIP地址的漂移情况。
三、Keepalived的工作原理是priority级别，谁级别高谁做老大，你可以提升或降低其优先级，看VIP地址发生漂移没？