CentOS6.2下搭建LVS(NAT)+Keepalived实现高性能高可用负载均衡

 

　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 keepalived
global_defs {
   router_id LVS_MASTER         #备上修改LVS_BACKUP
}
vrrp_instance VI_1 {
    state MASTER                #备上修改BACKUP
    interface eth0
    virtual_router_id 51
    priority 100                #备上修改80
    advert_int 1
    authentication {
        auth_type PASS
        auth_pass 1111
    }
    virtual_ipaddress {
        10.0.0.10
    }
}

vrrp_instance LAN_GATEWAY {
    state MASTER                 #备上修改BACKUP
    interface eth1
    virtual_router_id 52
    priority 100                 #备上修改80
    advert_int 1
    authentication {
        auth_type PASS
        auth_pass 1111
    }
    virtual_ipaddress {
        192.168.10.10
    }
}

virtual_server 10.0.0.10 80 {
    delay_loop 6
    lb_algo rr
    lb_kind NAT
#    nat_mask 255.255.255.0
#    persistence_timeout 50
    protocol TCP

    real_server 192.168.10.3 80 {
        weight 1
        TCP_CHECK {
        connect_timeout 10
        nb_get_retry 3
        connect_port 80
        }
    }
    real_server 192.168.10.4 80 {
        weight 1
        TCP_CHECK {
        connect_timeout 10
        nb_get_retry 3
        connect_port 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
[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：

启动LVS_Master，在查看LVS_Backup日志
[root@host2 ~]# tailf /var/log/messages
Mar 22 22:51:50 host2 Keepalived_vrrp: VRRP_Instance(LAN_GATEWAY) Received higher prio advert
Mar 22 22:51:50 host2 Keepalived_vrrp: VRRP_Instance(LAN_GATEWAY) Entering BACKUP STATE
Mar 22 22:51:50 host2 Keepalived_vrrp: VRRP_Instance(LAN_GATEWAY) removing protocol VIPs.
Mar 22 22:51:50 host2 Keepalived_vrrp: VRRP_Instance(VI_1) Received higher prio advert
Mar 22 22:51:50 host2 Keepalived_healthcheckers: Netlink reflector reports IP 192.168.10.10 removed
Mar 22 22:51:50 host2 Keepalived_vrrp: VRRP_Instance(VI_1) Entering BACKUP STATE
Mar 22 22:51:50 host2 Keepalived_vrrp: VRRP_Instance(VI_1) removing protocol VIPs.
Mar 22 22:51:50 host2 Keepalived_healthcheckers: Netlink reflector reports IP 10.0.0.10 removed
一切访问正常~！