CentOS6.2下搭建LVS(NAT)+Keepalived实现高性能高可用负载均衡-摩杜云开发者社区

　keepalived是一个类似于layer3, 4 & 5交换机制的软件，也就是我们平时说的第3层、第4层和第5层交换。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。

基于LVS（NAT）+ Keepalived实现高性能高可用负载均衡服务器。

其实NAT模式在企业用的不多，我和很多朋友都沟通过这个事情，我们搭建这个环节主要是测试一下整个性能与DR的具体的差距。但是在搭建这个环境过程中遇到一点小问题，就是

内网的VIP不知道如何去设置，这个问题困扰了我很长时间，因为LVS也只是刚刚接触，期间给我一个之前的学员电话他给我提供了一个方法，昨天晚上回去测试OK~！今天上午在线上也测试了，没有问题。以后要继续努力~！朝着我的目标前进~！同时希望各位在参考时遇到什么问题和我及时沟通，以便更好的完善文档！~

软件下载：
keepalived：http://www.keepalived.org/software/keepalived-1.2.2.tar.gz
ipvsadm: http://www.linuxvirtualserver.org/software/kernel-2.6/ipvsadm-1.26.tar.gz 注意：(for kernel 2.6.28-rc3 or later)
popt-static：http://mirror.centos.org/centos/6/os/x86_64/Packages/popt-static-1.13-7.el6.x86_64.rpm

实验拓扑图

1、在2台Director Server上分别配置LVS+Keepalived[root@host1 ~]# rpm -ivh popt-static-1.13-7.el6.x86_64.rpm

#看我前一篇文章http://crazylinux.blog.51cto.com/259244/811591

[root@host1 ~]# yum -y install kernel-devel make gcc openssl-devel lftp libnl* popt*

[root@host1 ~]# ln -s /usr/src/kernels/2.6.18-194.el5-x86_64/ /usr/src/linux

[root@host1 ~]# tar -zxvf ipvsadm-1.26.tar.gz -C /usr/src/

[root@host1 ~]# cd /usr/src/ipvsadm-1.26/

[root@host1 ipvsadm-1.26]# make

[root@host1 ipvsadm-1.26]# make install

[root@host1 ~]# tar -zxvf keepalived-1.2.2.tar.gz -C /usr/src/

[root@host1 ~]# cd /usr/src/keepalived-1.2.2/

[root@host1 keepalived-1.2.2]# ./configure

[root@host1 keepalived-1.2.2]# make

[root@host1 keepalived-1.2.2]# make install

[root@host1 keepalived-1.2.2]# cp /usr/local/etc/rc.d/init.d/keepalived /etc/rc.d/init.d/

[root@host1 keepalived-1.2.2]# cp /usr/local/etc/sysconfig/keepalived /etc/sysconfig/

[root@host1 keepalived-1.2.2]# mkdir /etc/keepalived

[root@host1 keepalived-1.2.2]# cp /usr/local/etc/keepalived/keepalived.conf /etc/keepalived/

[root@host1 keepalived-1.2.2]# cp /usr/local/sbin/keepalived /usr/sbin/

2 、开启路由转发[root@host1 ~]# vim /etc/sysctl.conf

net.ipv4.ip_forward = 1

[root@host1 ~]# sysctl -p

3、配置Keepalived
[root@host1 ~]# less /etc/keepalived/keepalived.conf

! Configuration File for
global_defs {
#备上修改LVS_BACKUP
}
vrrp_instance VI_1 {
#备上修改BACKUP
interface eth0
51
100 #备上修改80
1
authentication {
auth_type PASS
1111
}
virtual_ipaddress {
10.0.0.10
}
}
vrrp_instance LAN_GATEWAY {
#备上修改BACKUP
interface eth1
52
100 #备上修改80
1
authentication {
auth_type PASS
1111
}
virtual_ipaddress {
192.168.10.10
}
}
virtual_server 10.0.0.10 80
6
lb_algo rr
lb_kind NAT
# nat_mask 255.255.255.0
# persistence_timeout 50
protocol TCP
192.168.10.3 80
1
TCP_CHECK {
10
nb_get_retry 3
80
}
}
192.168.10.4 80
1
TCP_CHECK {
10
3
80
}
}
}

BACKUP服务器同上配置，先安装lvs再按装keepalived,然后配置/etc/keepalived/keepalived.conf，只需将批注部分改一下即可。

4、分别在2台Real Server上面设置网关把网关都设置成：192.168.10.10

5、在2台RealServer中分别配置HTTP[root@host3 ~]# yum -y install httpd [root@host3 ~]# cd /var/www/html/

[root@host3 html]# cat index.html

<h1>RealServer for 192.168.10.3</h1>

[root@host3 html]# /etc/init.d/httpd start

另一台机器配置一样，过程略、、、

6、测试：
分别启动Keepalived

[root@host1 ~]# chkconfig keepalived on

[root@host1 ~]# /etc/init.d/keepalived restart

[root@host1 ~]# ipvsadm -ln

IP Virtual Server version 1.2.1 (size=4096)

Prot LocalAddress:Port Scheduler Flags

-> RemoteAddress:Port Forward Weight ActiveConn InActConn

TCP 10.0.0.10:80 rr

-> 192.168.10.3:80 Masq 1 0 0

-> 192.168.10.4:80 Masq 1 0 0

先关闭LVS_Master的Keepalived，观察LVS_Backup的日志

[root@host2 ~]# tailf /var/log/messages

Mar 22 22:39:16 host2 Keepalived_vrrp: VRRP_Instance(LAN_GATEWAY) Transition to MASTER STATE

Mar 22 22:39:16 host2 Keepalived_vrrp: VRRP_Instance(VI_1) Transition to MASTER STATE

Mar 22 22:39:17 host2 Keepalived_vrrp: VRRP_Instance(LAN_GATEWAY) Entering MASTER STATE

Mar 22 22:39:17 host2 Keepalived_vrrp: VRRP_Instance(LAN_GATEWAY) setting protocol VIPs.

Mar 22 22:39:17 host2 Keepalived_vrrp: VRRP_Instance(LAN_GATEWAY) Sending gratuitous ARPs on eth1 for 192.168.10.10

Mar 22 22:39:17 host2 Keepalived_vrrp: VRRP_Instance(VI_1) Entering MASTER STATE

Mar 22 22:39:17 host2 Keepalived_vrrp: VRRP_Instance(VI_1) setting protocol VIPs.

Mar 22 22:39:17 host2 Keepalived_vrrp: VRRP_Instance(VI_1) Sending gratuitous ARPs on eth0 for 10.0.0.10

Mar 22 22:39:17 host2 Keepalived_healthcheckers: Netlink reflector reports IP 192.168.10.10 added

Mar 22 22:39:17 host2 Keepalived_healthcheckers: Netlink reflector reports IP 10.0.0.10 added

Mar 22 22:39:22 host2 Keepalived_vrrp: VRRP_Instance(LAN_GATEWAY) Sending gratuitous ARPs on eth1 for 192.168.10.10

Mar 22 22:39:22 host2 Keepalived_vrrp: VRRP_Instance(VI_1) Sending gratuitous ARPs on eth0 for 10.0.0.10

在测试机上访问：

在2台RealServer中分别配置HTTP

[root@host3 ~]# yum -y install httpd

[root@host3 ~]# cd /var/www/html/

[root@host3 html]# cat index.html

<h1>RealServer for 192.168.10.3</h1>

[root@host3 html]# /etc/init.d/httpd start

另一台机器配置一样，过程略、、、

7、测试：
分别启动Keepalived