LVS+keepalived高可用负载均衡
Keepalived简介：Keepalived的作用是检测web服务器的状态，如果有一台web服务器死机，或工作出现故障，Keepalived将检测到，并将有故障的web服务器从系统中剔除，当web服务器工作正常后Keepalived自动将web服务器加入到服务器群中，这些工作全部自动完成，不需要人工干涉，需要人工做的只是修复故障的web服务器。
实验环境
LVS-DR-Master192.168.3.11
LVS-DR-BACKUP192.168.3.12
LVS-DR-VIP192.168.3.254
WEB2-Realserver192.168.3.13
WEB1-Realserver192.168.3.14
关闭防火墙
service iptables stop
setenforce 0
Keepalvied 官网：http://www.keepalived.org
1.master和slave安装依赖包
yum -y install ipvsadm kernel-devel openssl-devel popt-devel
rpm安装
# rpm -ivh /mnt/Cluster/ipvsadm-1.24-10.i386.rpm
# rpm -ivh /mnt/Server/kernel-devel-2.6.18-194.el5.i686.rpm
# rpm -ivh /mnt/Server/openssl-devel-0.9.8e-12.el5_4.6.i386.rpm
# rpm -ivh /mnt/Server/popt-1.10.2.3-18.el5.i386.rpm
一、安装web服务器（yum）
1.安装WEB1-Realserver
# yum -y install httpd
# service httpd restart
# vim /var/www/html/index.html
aaaaaaaaaaaaaaaaaaaa
# service httpd restart
# elinks --dump http://localhost
aaaaaaaaaaaaaaaaaaaa
2.安装WEB2-Realserver
# yum -y install httpd
# service httpd restart
# vim /var/www/html/index.html
bbbbbbbbbbbbbbbbbbbbbbb
# service httpd restart
# elinks --dump http://localhost
bbbbbbbbbbbbbbbbbbbbbbb
二、配置LVS-DR-Master
1.编译安装keepalived
# tar xf keepalived-1.2.2.tar.gz
# cd keepalived-1.2.2
# ./configure --prefix=/ --with-kernel-dir=/usr/src/kernels/2.6.18-194.el5-i686/
# make && make install
RHEL5.5 32位上编译安装keepalived-1.2.2.tar.gz报错
报错信息如下：
/root/keepalived-1.2.2/keepalived/vrrp/vrrp.c:787: undefined reference to `ipvs_syncd_backup'
collect2: ld 返回 1
make: *** 错误 1
make: Leaving directory `/root/keepalived-1.2.2/keepalived'
make: *** 错误 2
解决方法：
vi keepalived/libipvs-2.6/ip_vs.h
#include
#include
这两行先后顺序错误
#include 在#include 的前面。
2.添加系统服务
# chkconfig --add keepalived
# chkconfig keepalived on
# chkconfig --list keepalived
keepalived 0:关闭1:关闭2:启用3:启用4:启用5:启用6:关闭
# service keepalived restart
3.设置网卡ip地址
# vim /etc/sysconfig/network-scripts/ifcfg-eth0
# Advanced Micro Devices 79c970
DEVICE=eth0
BOOTPROTO=none
ONBOOT=yes
HWADDR=00:0c:29:2d:8b:e8
NETMASK=255.255.255.0
IPADDR=192.168.3.11
TYPE=Ethernet
# service network restart
4.配置keepalived.conf
# cd /etc/keepalived/
# cp keepalived.conf{,.bak}
# vim keepalived.conf
! Configuration File for keepalived
global_defs {
notification_email {
fu_zhenyang@163.com
}
notification_email_from root@example.com
smtp_server 127.0.0.1
smtp_connect_timeout 30
router_id LVS_MASTER
}
vrrp_instance VI_1 {
state MASTER
interface eth0
virtual_router_id 51
priority 100
advert_int 1
authentication {
auth_type PASS
auth_pass 123456
}
virtual_ipaddress {
192.168.3.254
}
}
virtual_server 192.168.3.254 80 {
delay_loop 6
lb_algo wrr
lb_kind DR
persistence_timeout 50
protocol TCP
real_server 192.168.3.14 80 {
weight 1
TCP_CHECK {
connect_timeout 10
nb_get_retry 3
delay_before_retry 3
connect_port 80
}
}
real_server 192.168.3.13 80 {
weight 1
TCP_CHECK {
connect_timeout 10
nb_get_retry 3
delay_before_retry 3
connect_port 80
}
}
}
# service keepalived restart
# chkconfig keepalived on
三、配置LVS-DR-BACKUP
1.编译安装keepalived
# tar xf keepalived-1.2.2.tar.gz
# cd keepalived-1.2.2
#./configure --prefix=/ --with-kernel-dir=/usr/src/kernels/2.6.18-194.el5-i686/
# make && make install
2.设置网卡ip地址
# vim /etc/sysconfig/network-scripts/ifcfg-eth0
# Advanced Micro Devices 79c970
DEVICE=eth0
BOOTPROTO=none
ONBOOT=yes
HWADDR=00:0c:29:48:02:53
NETMASK=255.255.255.0
IPADDR=192.168.3.12
TYPE=Ethernet
# service network restart
正在关闭接口 eth0： [确定]
关闭环回接口： [确定]
弹出环回接口： [确定]
弹出界面 eth0： [确定]
3.配置keepalived.conf
# cd /etc/keepalived/
# cp keepalived.conf{,.bak}
# vim keepalived.conf
! Configuration File for keepalived
global_defs {
notification_email {
fu_zhenyang@163.com
}
notification_email_from root@example.com
smtp_server 127.0.0.1
smtp_connect_timeout 30
router_id LVS_MASTER
}
vrrp_instance VI_2 {
state SLAVE
interface eth0
virtual_router_id 51
priority 50
advert_int 1
authentication {
auth_type PASS
auth_pass 123456
}
virtual_ipaddress {
192.168.3.254
}
}
virtual_server 192.168.3.254 80 {
delay_loop 6
lb_algo wrr
lb_kind DR
persistence_timeout 50
protocol TCP
real_server 192.168.3.14 80 {
weight 1
TCP_CHECK {
connect_timeout 10
nb_get_retry 3
delay_before_retry 3
connect_port 80
}
}
real_server 192.168.3.13 80 {
weight 1
TCP_CHECK {
connect_timeout 10
nb_get_retry 3
delay_before_retry 3
connect_port 80
}
}
}
# service keepalived restart
# chkconfig keepalived on
四、配置Realserver
1.编写脚本
# vim realserver.sh
#!/bin/bash
SNS_VIP=192.168.3.254
. /etc/rc.d/init.d/functions
case "$1" in
start)
ifconfig lo:0 $SNS_VIP netmask 255.255.255.255 broadcast $SNS_VIP
/sbin/route add -host $SNS_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"
;;
stop)
ifconfig lo:0 down
route del $SNS_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"
;;
*)
echo "Usage: $0 {start|stop}"
exit 1
esac
exit 0
# chmod +x realserver.sh
# ./realserver.sh
RealServer Start OK
在 RealServer2 上的设置
# vim realserver.sh
#!/bin/bash
SNS_VIP=192.168.3.254
. /etc/rc.d/init.d/functions
case "$1" in
start)
ifconfig lo:0 $SNS_VIP netmask 255.255.255.255 broadcast $SNS_VIP
/sbin/route add -host $SNS_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"
;;
stop)
ifconfig lo:0 down
route del $SNS_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"
;;
*)
echo "Usage: $0 {start|stop}"
exit 1
esac
exit 0
# chmod +x realserver.sh
# ./realserver.sh start
RealServer Start OK
五、测试
(1).首先在master上查看一下IP地址（是否有VIP）
# ip a
1: lo:mtu 16436 qdisc noqueue
link/loopback 00:00:00:00:00:00 brd 00:00:00:00:00:00
inet 127.0.0.1/8 scope host lo
inet6 ::1/128 scope host
valid_lft forever preferred_lft forever
2: eth0:mtu 1500 qdisc pfifo_fast qlen 1000
link/ether 00:0c:29:2d:8b:e8 brd ff:ff:ff:ff:ff:ff
inet 192.168.3.11/24 brd 192.168.3.255 scope global eth0
inet 192.168.3.254/32 scope global eth0
inet6 fe80::20c:29ff:fe2d:8be8/64 scope link
valid_lft forever preferred_lft forever
3: sit0:mtu 1480 qdisc noop
link/sit 0.0.0.0 brd 0.0.0.0
(2)客户端访问：http://192.168.3.254
刷新查看是否一直切换显示页面
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