基于keepalived双主模型的高可用LVS

背景知识：

　　keepalived：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。

　　LVS：LVS是Linux Virtual Server的简写，意即Linux虚拟服务器，是一个虚拟的服务器集群系统。

实验系统：CentOS 6.6_x86_64

实验前提：提前准备好编译环境，防火墙和selinux都关闭

实验说明：本实验共有4台主机，其中keep1和keep2为2台前端的keepalived服务器，real1和real2为LVS中的realserver，IP地址对应如拓扑图。

实验软件：httpd-2.2.15　keepalived-1.2.19

实验拓扑：

一、配置realserver

　　1.安装httpd：

yum -y install httpd

　　2.配置内核参数：

echo  > /proc/sys/net/ipv4/conf/lo/arp_ignore           //仅在请求的地址配置在请求报文的接口进行响应
echo  > /proc/sys/net/ipv4/conf/all/arp_ignore
echo  > /proc/sys/net/ipv4/conf/lo/arp_announce         //表示仅通告网络直连的接口的地址
echo  > /proc/sys/net/ipv4/conf/all/arp_announce

　　3.增加测试页面并配置VIP：

　　　　real1上：

ifconfig lo: 192.168.19.150 netmask 255.255.255.255 broadcast 192.168.19.150 up    //配置VIP
ifconfig lo:1 192.168.19.151 netmask 255.255.255.255 broadcast 192.168.19.151 up
route add -host 192.168.19.150 dev lo:0                                             //配置路由
route add -host 192.168.19.151 dev lo:1
vim /var/www/html/index.html
---------------------------------------------
<h1>realserver1</h1>
---------------------------------------------
service httpd start

　　　　real2上：

ifconfig lo:0 192.168.19.150 netmask 255.255.255.255 broadcast 192.168.19.150 up
ifconfig lo:1 192.168.19.151 netmask 255.255.255.255 broadcast 192.168.19.151 up
route add -host 192.168.19.150 dev lo:0
route add -host 192.168.19.151 dev lo:1
vim /var/www/html/index.html
---------------------------------------------
<h1>realserver2</h1>
---------------------------------------------
service httpd start

二、安装并配置keepalived

　　1.编译安装keepalived，在keep1和keep2上操作：

wget http://www.keepalived.org/software/keepalived-1.2.19.tar.gz
tar xf keepalived-1.2..tar.gz
cd keepalived-1.2.19
./configure --prefix=/usr/local/keepalived --sbindir=/usr/sbin/ --sysconfdir=/etc/ --mandir=/usr/local/share/man/ --with-kernel-dir=/usr/src/kernels/2.6.32-504.30.3.el6.x86_64/      //内核版本换成自己主机的
make && make install
chkconfig --add keepalived
chkconfig keepalived on
yum -y install ipvsadm                //安装LVS工具

　　2.配置keepalived：

　　　　keep1上：

vim /etc/keepalived/keepalived.conf
----------------------------------------------------
vrrp_instance VI_1 {
    state MASTER
    interface eth0
    virtual_router_id
    priority
    advert_int
    authentication {
        auth_type PASS
        auth_pass abcd
    }
    virtual_ipaddress {
        192.168.19.150
    }
}vrrp_instance VI_2 {
    state BACKUP
    interface eth0
    virtual_router_id
    priority
    advert_int
    authentication {
        auth_type PASS
        auth_pass abcd
    }
    virtual_ipaddress {
        192.168.19.151
    }
}virtual_server 192.168.19.150  {
    delay_loop
    lb_algo rr                         //LVS算法
    lb_kind DR                         //调度类型
    protocol TCP    real_server 192.168.19.29 80 {
            weight 1
　　　　　　  inhibit_on_failure
            TCP_CHECK {
            connect_timeout 3
            nb_get_retry 2
            delay_before_retry 1
            connect_port 80
            }
        }    real_server 192.168.19.34 80 {
            weight 1
　　　　　　  inhibit_on_failure
            TCP_CHECK {
            connect_timeout 3
            nb_get_retry 2
            delay_before_retry 1
            connect_port 80
            }
        }
}virtual_server 192.168.19.151  {
    delay_loop
    lb_algo rr
    lb_kind DR
    protocol TCP    real_server 192.168.19.29 80 {
            weight 1
　　　　　　  inhibit_on_failure
            TCP_CHECK {
            connect_timeout 3
            nb_get_retry 2
            delay_before_retry 1
            connect_port 80
            }
        }    real_server 192.168.19.34 80 {
            weight 1
　　　　　　  inhibit_on_failure
            TCP_CHECK {
            connect_timeout 3
            nb_get_retry 2
            delay_before_retry 1
            connect_port 80
            }
        }
}

　　　　keep2上：

vim /etc/keepalived/keepalived.conf 
----------------------------------------------

vrrp_instance VI_1 {
    state BACKUP
    interface eth0
    virtual_router_id 31
    priority 99
    advert_int 1
    authentication {
        auth_type PASS
        auth_pass abcd
    }
    virtual_ipaddress {
        192.168.19.150
    }
}vrrp_instance VI_2 {
    state MASTER
    interface eth0
    virtual_router_id 41
    priority 100
    advert_int 1
    authentication {
        auth_type PASS
        auth_pass abcd
    }
    virtual_ipaddress {
        192.168.19.151
    }
}virtual_server 192.168.19.150 80 {
    delay_loop 6
    lb_algo rr
    lb_kind DR
    protocol TCP    real_server 192.168.19.29 80 {
            weight 1
            inhibit_on_failure
            TCP_CHECK {
            connect_timeout 3
            nb_get_retry 2
            delay_before_retry 1
            connect_port 80
            }
        }    real_server 192.168.19.34 80 {
            weight
            inhibit_on_failure
            TCP_CHECK {
            connect_timeout 3
            nb_get_retry 2
            delay_before_retry 1
            connect_port 80
            }
        }
}virtual_server 192.168.19.151 80 {
    delay_loop 6
    lb_algo rr
    lb_kind DR
    protocol TCP    real_server 192.168.19.29 80 {
            weight 1
            inhibit_on_failure
            TCP_CHECK {
            connect_timeout 3
            nb_get_retry 2
            delay_before_retry 1
            connect_port 80
            }
        }    real_server 192.168.19.34 80 {
            weight
            inhibit_on_failure
            TCP_CHECK {
            connect_timeout 3
            nb_get_retry 2
            delay_before_retry 1
            connect_port 80
            }
        }
}

　　3.两台机器启动keepalived：

service keepalived start
ipvsadm -L -n              //用LVS工具查看keepalived运行
ip addr show               //查看VIP

　　　　两台机器上LVS规则都已经生效，且2个VIP分别运行在2个节点：

　　　　　　keep1上：

　　　　　　keep2上：

　　　　分别打开测试页面进行测试：

　　　　停掉任何一个节点，资源都会自动转移：

　　至此，演示完毕，谢谢！如有问题，请与我联系，QQ：82800452

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