LVS只是做一个负载均衡，通过访问VIP来访问后端的网站程序，一旦LVS宕机，整个网站就访问不了，这就出现了单点。所以要结合keepalive这种高可用软件来保证整个网站的高可用。本文将介绍如何利用keepalive来实现LVS的高可用(以LVS的DR模式为例，生产环境后台的real server 网站内容是一致的，为了看到实验效果，这里是两个不同的页面)。
一、环境介绍
VIP：192.168.1.188
RIP1(Web1): 192.168.1.2
RIP2(Web2): 192.168.1.5
LVS1 :192.168.1.6
LVS2: 192.168.1.7
web1页面
web2页面
二、配置realserver
分别在web1和web2上执行lvs_rserver.sh
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[root@web1 ~]
# ./lvs_rserver.sh start
RealServer Start OK
[root@web1 ~]
#
[root@web2 ~]
# ./lvs_rserver.sh start
RealServer Start OK
[root@web2 ~]
#
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lvs_rserver.sh脚本内容如下：
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[root@web1 ~]
# cat lvs_rserver.sh
#!/bin/sh
#LVS Client Server
VIP=192.168.1.188
case
$1
in
start)
ifconfig
lo:0 $VIP netmask 255.255.255.255 broadcast $VIP
/sbin/route
add –host $VIP dev lo:0
echo
"1"
>
/proc/sys/net/ipv4/conf/lo/arp_ignore
echo
"2"
>
/proc/sys/net/ipv4/conf/lo/arp_announce
echo
"1"
>
/proc/sys/net/ipv4/conf/all/arp_ignore
echo
"2"
>
/proc/sys/net/ipv4/conf/all/arp_announce
sysctl -p >
/dev/null
2>&1
echo
"RealServer Start OK"
exit
0
;;
stop)
ifconfig
lo:0 down
route del $VIP >
/dev/null
2>&1
echo
"0"
>
/proc/sys/net/ipv4/conf/lo/arp_ignore
echo
"0"
>
/proc/sys/net/ipv4/conf/lo/arp_announce
echo
"0"
>
/proc/sys/net/ipv4/conf/all/arp_ignore
echo
"0"
>
/proc/sys/net/ipv4/conf/all/arp_announce
echo
"RealServer Stoped OK"
exit
1
;;
*)
echo
"Usage: $0 {start|stop}"
;;
esac
[root@web2 ~]
#
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三、安装配置lvs及keepalive
分别在lvs1和lvs2上安装lvs及keepalive
lvs及keppalive的安装见《构建负载均衡服务器之二 LVS详解及应用》 《构建高可用服务器之一 Keepalive介绍及安装》
在lvs1和lvs2上配置VIP并加载相关模块
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[root@lvs1 ~]
# ifconfig eth0:0192.168.1.188 netmask 255.255.255.0
[root@lvs1 ~]
# modprobe ip_vs
[root@lvs1 ~]
# modprobe ip_vs_rr
[root@lvs1 ~]
# modprobe ip_vs_wrr
[root@lvs1 ~]
#
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[root@lvs2 ~]
# ifconfig eth0:0192.168.1.188 netmask 255.255.255.0
[root@lvs2 ~]
# modprobe ip_vs
[root@lvs2 ~]
# modprobe ip_vs_rr
[root@lvs2 ~]
# modprobe ip_vs_wrr
[root@lvs2 ~]
#
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在lvs1上修改keepalive.conf文件，修改后内容如下
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[root@lvs1 ~]
# vim/etc/keepalived/keepalived.conf
[root@lvs1 ~]
# cat/etc/keepalived/keepalived.conf
! Configuration File
for
keepalived
global_defs {
notification_email {
654001593@qq.com
}
notification_email_from 654001593@qq.com
smtp_server 127.0.0.1
smtp_connect_timeout 30
router_id LVS_DEVEL
}
# VIP1
vrrp_instance VI_1 {
state MASTER
interface eth0
lvs_sync_daemon_inteface eth0
virtual_router_id 51
priority 100
advert_int 5
nopreempt
authentication {
auth_type PASS
auth_pass 1111
}
virtual_ipaddress {
192.168.1.188
}
}
virtual_server 192.168.1.188 80 {
delay_loop 6
lb_algo wrr
lb_kind DR
# persistence_timeout 60
protocol TCP
real_server 192.168.1.2 80 {
weight 100
TCP_CHECK {
connect_timeout 10
nb_get_retry 3
delay_before_retry 3
connect_port 80
}
}
real_server 192.168.1.5 80 {
weight 100
TCP_CHECK {
connect_timeout 10
nb_get_retry 3
delay_before_retry 3
connect_port 80
}
}
}
[root@lvs1 ~]
#
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lvs2上的keepalive.conf文件基本和lvs1上的一致，但是state这一项lvs1上是MASTER，而lvs2上的BACKUP；优先级priority在lvs1上为100，在lvs2上为90
在lvs2上修改keepalive.conf文件，修改后内容如下
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[root@lvs2 ~]
# cat/etc/keepalived/keepalived.conf
! Configuration File
for
keepalived
global_defs {
notification_email {
654001593@qq.com
}
notification_email_from 654001593@qq.com
smtp_server 127.0.0.1
smtp_connect_timeout 30
router_id LVS_DEVEL
}
# VIP1
vrrp_instance VI_1 {
state BACKUP
interface eth0
lvs_sync_daemon_inteface eth0
virtual_router_id 51
priority 90
advert_int 5
nopreempt
authentication {
auth_type PASS
auth_pass 1111
}
virtual_ipaddress {
192.168.1.188
}
}
virtual_server 192.168.1.188 80 {
delay_loop 6
lb_algo wrr
lb_kind DR
# persistence_timeout 60
protocol TCP
real_server 192.168.1.2 80 {
weight 100
TCP_CHECK {
connect_timeout 10
nb_get_retry 3
delay_before_retry 3
connect_port 80
}
}
real_server 192.168.1.5 80 {
weight 100
TCP_CHECK {
connect_timeout 10
nb_get_retry 3
delay_before_retry 3
connect_port 80
}
}
}
[root@lvs2 ~]
#
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四、测试
停掉lvs1的网卡
去ping VIP一样一直在通信(配置有nopreempt)
通过VIP访问网站
刷新
即使lvs1宕机后又恢复，此时依旧是通过lvs2访问(由是否配置nopreempt决定）。
本文转自Jacken_yang 51CTO博客，原文链接：http://blog.51cto.com/linuxnote/1655103，如需转载请自行联系原作者
