LVS +DR +keepalived高可用性web集群

kllhi

准备机器

    LVS_MASTER - 172.16.8.129
    LVS_BACKUP - 172.16.8.130
    WEB_APP_SERVER_1 - 172.16.8.131
    WEB_APP_SERVER_2 - 172.16.8.132

注:

    virtual server: 172.16.8.252 (非真实机器, 只需要在web app server上配下这个IP)
    所有机器都安装的Debian 7.5 (wheezy)

安装软件
LVS_MASTER上安装配置LVS和keepalived

$ ssh LVS_MASTER
$ sudo apt-get install ipvsadm keepalived

配置LVS

$ cat /etc/default/ipvsadm
# ipvsadm

# if you want to start ipvsadm on boot set this to true
AUTO="false"

# daemon method (none|master|backup)
DAEMON="master"

# use interface (eth0,eth1...)
IFACE="eth0"

# syncid to use
SYNCID="1"

配置keepalived

$ cat /etc/keepalived/keepalived.conf
global_defs {
   router_id LVS_MASTER   #BACKUP上修改为LVS_BACKUP
}

vrrp_instance VI_1 {
    state MASTER          #BACKUP上修改为BACKUP
    interface eth0
    virtual_router_id 51  #与备机的id必须一致
    priority 100          #BACKUP上修改为80
    advert_int 1
    authentication {
        auth_type PASS
        auth_pass 1111
    }
    virtual_ipaddress {
        172.16.8.252     #virtual server
    }
}

virtual_server 172.16.8.252 80 {
    delay_loop 6
    lb_algo rr
    lb_kind DR
    #lb_kind NAT
    #persistence_timeout 5
    protocol TCP

    real_server 172.16.8.131 80 {
        weight 3
        TCP_CHECK {
            connect_timeout 3
            nb_get_retry 3
            delay_before_retry 3
            connect_port 80
        }
    }

    real_server 172.16.8.132 80 {
        weight 3
        TCP_CHECK {
            connect_timeout 3
            nb_get_retry 3
            delay_before_retry 3
            connect_port 80
        }
    }
}

LVS_BACKUP上安装配置LVS和keepalived

$ ssh LVS_BACKUP
$ sudo apt-get install ipvsadm keepalived

配置LVS

$ cat /etc/default/ipvsadm
# ipvsadm

# if you want to start ipvsadm on boot set this to true
AUTO="false"

# daemon method (none|master|backup)
DAEMON="backup"

# use interface (eth0,eth1...)
IFACE="eth0"

# syncid to use
SYNCID="1"

配置keepalived

$ cat /etc/keepalived/keepalived.conf
global_defs {
   router_id LVS_BACKUP #BACKUP上修改为LVS_BACKUP
}

vrrp_instance VI_1 {
    state BACKUP          #BACKUP上修改为BACKUP
    interface eth0
    virtual_router_id 51  #与备机的id必须一致
    priority 80           #BACKUP上修改为80
    advert_int 1
    authentication {
        auth_type PASS
        auth_pass 1111
    }
    virtual_ipaddress {
        172.16.8.252     #virtual server
    }
}

virtual_server 172.16.8.252 80 {
    delay_loop 6
    lb_algo rr
    lb_kind DR
    #lb_kind NAT
    #persistence_timeout 5
    protocol TCP

    real_server 172.16.8.131 80 {
        weight 3
        TCP_CHECK {
            connect_timeout 3
            nb_get_retry 3
            delay_before_retry 3
            connect_port 80
        }
    }

    real_server 172.16.8.132 80 {
        weight 3
        TCP_CHECK {
            connect_timeout 3
            nb_get_retry 3
            delay_before_retry 3
            connect_port 80
        }
    }
}

配置WEB_APP_SERVER_1
安装nginx

$ ssh WEB_APP_SERVER_1
$ sudo apt-get install nginx
$ sudo bash -c 'echo "Web App Server 1" > /usr/share/nginx/www/index.html'

配置IP

$ sudo ifconfig eth0:0 172.16.8.252 netmask 255.255.255.255 up

修改配置文件 （上面的配置重启后需要重新输入命令）

$ cat /etc/network/interfaces
# This file describes the network interfaces available on your system
# and how to activate them. For more information, see interfaces(5).

# The loopback network interface
auto lo
auto eth0
auto eth0:0

iface lo inet loopback

# The primary network interface
allow-hotplug eth0
#iface eth0 inet dhcp
iface eth0 inet static
        address 172.16.8.131
        netmask 255.255.255.0
        gateway 172.16.8.2

iface eth0:0 inet static
        address 172.16.8.252
        netmask 255.255.255.255
        gateway 172.16.8.2

配置WEB_APP_SERVER_2
安装nginx

$ ssh WEB_APP_SERVER_2
$ sudo apt-get install nginx
$ sudo bash -c 'echo "Web App Server 2" > /usr/share/nginx/www/index.html'

配置IP

$ sudo ifconfig eth0:0 172.16.8.252 netmask 255.255.255.255 up

修改配置文件 （上面的配置重启后需要重新输入命令）

$ cat /etc/network/interfaces
# This file describes the network interfaces available on your system
# and how to activate them. For more information, see interfaces(5).

# The loopback network interface
auto lo
auto eth0
auto eth0:0

iface lo inet loopback

# The primary network interface
allow-hotplug eth0
#iface eth0 inet dhcp
iface eth0 inet static
        address 172.16.8.132
        netmask 255.255.255.0
        gateway 172.16.8.2

iface eth0:0 inet static
        address 172.16.8.252
        netmask 255.255.255.255
        gateway 172.16.8.2

启动LVS, keepalived

$ ssh LVS_MASTER
$ sudo service ipvsadm restart
$ sudo service keepalived restart

$ ssh LVS_BACKUP
$ sudo service ipvsadm restart
$ sudo service keepalived restart

测试
查看服务器状态

$ while true; do curl 172.16.8.252; curl 172.16.8.252; sleep 1; done
Web App Server 1
Web App Server 2
Web App Server 1
Web App Server 2
...

$ ssh LVS_MASTER
$ sudo ipvsadm -ln
IP Virtual Server version 1.2.1 (size=4096)
Prot LocalAddress:Port Scheduler Flags
  -> RemoteAddress:Port           Forward Weight ActiveConn InActConn
TCP  172.16.8.252:80 rr
  -> 172.16.8.131:80              Route   3      0          29
  -> 172.16.8.132:80              Route   3      0          30

将WEB_APP_SERVER_1的nginx进程结束，查看效果

$ ssh WEB_APP_SERVER_1
$ sudo service nginx stop

$ while true; do curl 172.16.8.252; curl 172.16.8.252; sleep 1; done
curl: (7) couldn't connect to host
Web App Server 2
curl: (7) couldn't connect to host
Web App Server 2
curl: (7) couldn't connect to host
Web App Server 2
Web App Server 2
Web App Server 2
Web App Server 2
...

$ sudo ipvsadm -ln
IP Virtual Server version 1.2.1 (size=4096)
Prot LocalAddress:Port Scheduler Flags
  -> RemoteAddress:Port           Forward Weight ActiveConn InActConn
TCP  172.16.8.252:80 rr
  -> 172.16.8.132:80              Route   3      0          114

$ ssh WEB_APP_SERVER_1
$ sudo service nginx stop

$ while true; do curl 172.16.8.252; curl 172.16.8.252; sleep 1; done
Web App Server 1
Web App Server 2
Web App Server 1
Web App Server 2
...

将LVS_MASTER关闭，查看请求web app server的结果

$ ssh LVS_MASTER
$ sudo shutdown -h now

$ while true; do curl 172.16.8.252; curl 172.16.8.252; sleep 1; done
Web App Server 1
Web App Server 2
Web App Server 1
Web App Server 2
...