通过keepalived实现lvs服务器的的双机热备和真实服务器之间的负载均衡的blog挺多的，在搭建的时候也参考了相关博文，不同人搭建的实验环境不一样，本文是基于VM搭建的虚拟集群环境，全部虚拟机网卡模式为NAT方式相连，处于同一网段。
搭建环境：
使用redhead 2.6.32-431.el6.x86_64版本的linux，创建四台，配置相关网络信息，确保同一网段下。
配置好各自ip即可，虚拟ip在配置lvs时设定。
安装配置LVS
1.在主备Lvs上安装ipvsadm和keepalived
LVS是通过IPVS模块实现的，检查kernel是否支持LVS的IPVS模块，再安装IPVS管理软件ipvsadm
[root@rex ~]# modprobe -l | grep ipvs
kernel/net/netfilter/ipvs/ip_vs.ko
kernel/net/netfilter/ipvs/ip_vs_rr.ko
kernel/net/netfilter/ipvs/ip_vs_wrr.ko
kernel/net/netfilter/ipvs/ip_vs_lc.ko
kernel/net/netfilter/ipvs/ip_vs_wlc.ko
kernel/net/netfilter/ipvs/ip_vs_lblc.ko
kernel/net/netfilter/ipvs/ip_vs_lblcr.ko
kernel/net/netfilter/ipvs/ip_vs_dh.ko
kernel/net/netfilter/ipvs/ip_vs_sh.ko
kernel/net/netfilter/ipvs/ip_vs_sed.ko
kernel/net/netfilter/ipvs/ip_vs_nq.ko
kernel/net/netfilter/ipvs/ip_vs_ftp.ko
kernel/net/netfilter/ipvs/ip_vs_pe_sip.ko
安装ipvsadm
[root@rex ~]# yum install ipvsadm
能通过ipvsadm --help查看相关信息即安装成功。
安装keepalived
安装依赖库：yum install -y openssl openssl-devel（我是缺这两个，具体编译时候如果报错则安装相关提示补安装相关缺漏）
下载keepalived：
http://www.keepalived.org/software/keepalived-1.2.6.tar.gz
安装命令：
# tar zxvf keepalived-1.2.6.tar.gz
# cd keepalived-1.2.6
# ./configure --sysconf=/etc --with-kernel-dir=/lib/modules/2.6.32-431.el6.x86_64 #指定配置文件存放路径，指定使用内核源码中的头文件。
#make
#make install
#ln -s /usr/local/sbin/keepalived /sbin/ #把启动命令软连接到sbin，方便以后直接使用
能通过keepalived --help查看相关信息即安装成功。
配置LVS：
主LVS：
! Configuration File for keepalived
global_defs {
notification_email { #配置告警邮件发送
XXXX@qq.com
}
notification_email_from Keepalived@localhost
smtp_server 192.168.200.1
smtp_connect_timeout 30
router_id LVS_DEVEL
}
vrrp_instance VI_1 {
state MASTER #主LVS标志
interface eth1 #设置对外服务口
virtual_router_id 51
priority 100 #设置优先级，优先级高的为主机
advert_int 1 #设置同步时间间隔
authentication { #设置主备LVS验证类型和密码，两边必须一致
auth_type PASS
auth_pass 1111
}
virtual_ipaddress { #设置虚拟服务IP
192.168.153.110
}
}
virtual_server 192.168.153.110 80 {
delay_loop 6 #健康检查时间间隔
lb_algo rr #负载均衡算法，此为轮询算法
lb_kind DR #负载均衡转发规则，也就是IP转发规则，DR转发方式最快，但是所有机器必须在一个网段内，还有NAT和TUNEL两种转发方式
protocol TCP
real_server 192.168.153.131 80 {
weight 1
TCP_CHECK {
connect_timeout 3
nb_get_retry 3
delay_before_retry 3
}
}
real_server 192.168.153.135 80 {
weight 1
TCP_CHECK {
connect_timeout 3
nb_get_retry 3
delay_before_retry 3
}
}
}
备用LVS配置：复制上面配置修改两处即可：1.state MASTER改为state BACKUP 2.将priority 100改低，这里改为80
配置Realserver
对所有Realserver重复做一下步骤
在/etc/init.d下创建脚本lvsrs
1 #!/bin/bash
2
3 VIP=192.168.153.110
4 ./etc/rc.d/init.d/functions
5 case "$1" in
6 start)
7 echo "Start LVS of Realserver!"
8 /sbin/ifconfig lo:0 $VIP broadcast $VIP netmask 255.255.255.255 up
9 echo "1" >/proc/sys/net/ipv4/conf/lo/arp_ignore
10 echo "2" >/proc/sys/net/ipv4/conf/lo/arp_announce
11 echo "1" >/proc/sys/net/ipv4/conf/all/arp_ignore
12 echo "2" >/proc/sys/net/ipv4/conf/all/arp_announce
13
14 ;;
15
16 stop)
17
18 /sbin/ifconfig lo:0 down
19 echo "0" >/proc/sys/net/ipv4/conf/lo/arp_ignore
20 echo "0" >/proc/sys/net/ipv4/conf/lo/arp_announce
21 echo "0" >/proc/sys/net/ipv4/conf/all/arp_ignore
22 echo "0" >/proc/sys/net/ipv4/conf/all/arp_announce
23 echo "RealServer Stoped"
24
25 ;;
26
27 *)
28
29 echo "Usage: $0 {start|stop}"
30
31 exit 1
32
33 esac
修改其执行权限：chmod 755 /etc/init.d/lvsrs
执行启动脚本：
#service lvsrs start
查看其ip：
lo Link encap:Local Loopback
inet addr:127.0.0.1 Mask:255.0.0.0
inet6 addr: ::1/128 Scope:Host
UP LOOPBACK RUNNING MTU:16436 Metric:1
RX packets:8 errors:0 dropped:0 overruns:0 frame:0
TX packets:8 errors:0 dropped:0 overruns:0 carrier:0
collisions:0 txqueuelen:0
RX bytes:480 (480.0 b) TX bytes:480 (480.0 b)
lo:0 Link encap:Local Loopback
inet addr:192.168.153.110 Mask:255.255.255.255
UP LOOPBACK RUNNING MTU:16436 Metric:1
在realserver上安装apache并且启动！
在 /var/www/hmtl/下添加index.html测试主页，不同server用不同界面进行区分。
启动LVS并且测试：
主备LVS启动：/etc/init.d/keepalived start
查看启动状态：
主LVS：
Feb 4 20:11:41 rex Keepalived_vrrp[9522]: VRRP_Instance(VI_1) Transition to MASTER STATE
Feb 4 20:11:42 rex Keepalived_vrrp[9522]: VRRP_Instance(VI_1) Entering MASTER STATE
Feb 4 20:11:42 rex Keepalived_vrrp[9522]: VRRP_Instance(VI_1) setting protocol VIPs.
Feb 4 20:11:42 rex Keepalived_vrrp[9522]: VRRP_Instance(VI_1) Sending gratuitous ARPs on eth2 for 192.168.153.110
Feb 4 20:11:42 rex Keepalived_healthcheckers[9521]: Netlink reflector reports IP 192.168.153.110 added
Feb 4 20:11:47 rex Keepalived_vrrp[9522]: VRRP_Instance(VI_1) Sending gratuitous ARPs on eth2 for 192.168.153.110
备LVS：
Feb 4 20:18:16 rex Keepalived_vrrp[9522]: VRRP_Instance(VI_1) Received higher prio advert
Feb 4 20:18:16 rex Keepalived_vrrp[9522]: VRRP_Instance(VI_1) Entering BACKUP STATE
Feb 4 20:18:16 rex Keepalived_vrrp[9522]: VRRP_Instance(VI_1) removing protocol VIPs.
Feb 4 20:18:16 rex Keepalived_healthcheckers[9521]: Netlink reflector reports IP 192.168.153.110 removed
Feb 4 20:19:06 rex dhclient[1265]: DHCPREQUEST on eth2 to 192.168.153.254 port 67 (xid=0x6f9b7b38)
用ip addr和ipvsadm查看路由情况
主LVS# ip addr
1: lo:
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: eth1:
link/ether 00:0c:29:3e:ce:ce brd ff:ff:ff:ff:ff:ff
inet 192.168.153.133/24 brd 192.168.153.255 scope global eth1
inet 192.168.153.110/32 scope global eth1
inet6 fe80::20c:29ff:fe3e:cece/64 scope link
valid_lft forever preferred_lft forever
备LVS# ip addr
1: lo:
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: eth2:
link/ether 00:0c:29:0e:6c:b0 brd ff:ff:ff:ff:ff:ff
inet 192.168.153.134/24 brd 192.168.153.255 scope global eth2
inet6 fe80::20c:29ff:fe0e:6cb0/64 scope link
valid_lft forever preferred_lft forever
[root@rex ~]# ipvsadm
IP Virtual Server version 1.2.1 (size=4096)
Prot LocalAddress:Port Scheduler Flags
-> RemoteAddress:Port Forward Weight ActiveConn InActConn
TCP bogon:http rr
-> bogon:http Route 1 0 0
-> bogon:http Route 1 0 0
测试：
1.高可用×××测试--主备lvs切换
把主lvs stop！然后查看备lvs日志，然后把主恢复，再看备lvs的日志
Feb 4 20:11:41 rex Keepalived_vrrp[9522]: VRRP_Instance(VI_1) Transition to MASTER STATE
Feb 4 20:11:42 rex Keepalived_vrrp[9522]: VRRP_Instance(VI_1) Entering MASTER STATE
Feb 4 20:11:42 rex Keepalived_vrrp[9522]: VRRP_Instance(VI_1) setting protocol VIPs.
Feb 4 20:11:42 rex Keepalived_vrrp[9522]: VRRP_Instance(VI_1) Sending gratuitous ARPs on eth2 for 192.168.153.110
Feb 4 20:11:42 rex Keepalived_healthcheckers[9521]: Netlink reflector reports IP 192.168.153.110 added
Feb 4 20:11:47 rex Keepalived_vrrp[9522]: VRRP_Instance(VI_1) Sending gratuitous ARPs on eth2 for 192.168.153.110
Feb 4 20:18:16 rex Keepalived_vrrp[9522]: VRRP_Instance(VI_1) Received higher prio advert
Feb 4 20:18:16 rex Keepalived_vrrp[9522]: VRRP_Instance(VI_1) Entering BACKUP STATE
Feb 4 20:18:16 rex Keepalived_vrrp[9522]: VRRP_Instance(VI_1) removing protocol VIPs.
Feb 4 20:18:16 rex Keepalived_healthcheckers[9521]: Netlink reflector reports IP 192.168.153.110 removed
Feb 4 20:19:06 rex dhclient[1265]: DHCPREQUEST on eth2 to 192.168.153.254 port 67 (xid=0x6f9b7b38)
Feb 4 20:19:06 rex dhclient[1265]: DHCPACK from 192.168.153.254 (xid=0x6f9b7b38)
Feb 4 20:19:06 rex dhclient[1265]: bound to 192.168.153.134 -- renewal in 737 seconds.
Feb 4 20:19:06 rex NetworkManager[1241]:
Feb 4 20:19:06 rex NetworkManager[1241]:
Feb 4 20:19:06 rex NetworkManager[1241]:
Feb 4 20:19:06 rex NetworkManager[1241]:
Feb 4 20:19:06 rex NetworkManager[1241]:
Feb 4 20:19:06 rex NetworkManager[1241]:
2.负载均衡测试
在本地浏览器上访问192.168.153.110，不断刷新，可以看到代表不同realserver的主界面。
3.故障切换测试
把realserver1的服务stop掉，查看LVS的日志，然后恢复再看：
Feb 4 20:25:59 rex Keepalived_healthcheckers[9588]: Netlink reflector reports IP 192.168.153.110 added
Feb 4 20:26:04 rex Keepalived_vrrp[9589]: VRRP_Instance(VI_1) Sending gratuitous ARPs on eth1 for 192.168.153.110
Feb 4 20:27:53 rex Keepalived_healthcheckers[9588]: TCP connection to [192.168.153.135]:80 failed !!!
Feb 4 20:27:53 rex Keepalived_healthcheckers[9588]: Removing service [192.168.153.135]:80 from VS [192.168.153.110]:80
Feb 4 20:27:53 rex Keepalived_healthcheckers[9588]: Remote SMTP server [192.168.200.1]:25 connected.
Feb 4 20:28:14 rex Keepalived_healthcheckers[9588]: Error reading data from remote SMTP server [192.168.200.1]:25.
Feb 4 20:28:29 rex Keepalived_healthcheckers[9588]: TCP connection to [192.168.153.135]:80 success.
Feb 4 20:28:29 rex Keepalived_healthcheckers[9588]: Adding service [192.168.153.135]:80 to VS [192.168.153.110]:80
Feb 4 20:28:29 rex Keepalived_healthcheckers[9588]: Remote SMTP server [192.168.200.1]:25 connected.