LVS DR模式搭建、keepalived + LVS

18.11 LVS DR模式搭建

DR模式搭建-准备工作

• 三台机器

• 分发器，也叫调度器（简写为dir）
  分发器：192.168.21.130/24
  rs1:192.168.21.132/24
  rs2:192.168.21.133/24
  vip:192.168.21.200/24

• dir上编写脚本 vim /usr/local/sbin/lvs_dr.sh //内容如下

#! /bin/bash
echo 1 > /proc/sys/net/ipv4/ip_forward
ipv=/usr/sbin/ipvsadm
vip=192.168.21.200
rs1=192.168.21.132
rs2=192.168.21.133
#ifdown ifup 同等于重启网卡，对虚拟网卡进行重置
#防止再次启动脚本的时候，再次设置虚拟网卡的IP地址
ifdown ens33
ifup ens33
#注意这里的网卡名字
ifconfig ens33:2 $vip broadcast $vip netmask 255.255.255.255 up
route add -host $vip dev ens33:2
$ipv -C
$ipv -A -t $vip:80 -s rr
$ipv -a -t $vip:80 -r $rs1:80 -g -w 1
$ipv -a -t $vip:80 -r $rs2:80 -g -w 1

• 启动脚本

[root@qingyun-01 ~]# sh /usr/local/sbin/lvs_dr.sh
成功断开设备 'ens33'。
连接已成功激活（D-Bus 活动路径：/org/freedesktop/NetworkManager/ActiveConnection/4）

• 两台rs上也编写脚本 vim /usr/local/sbin/lvs_rs.sh //内容如下

#! /bin/bash
vip=192.168.21.200
ifdown lo
ifup lo
#把vip绑定在lo上，是为了实现rs直接把结果返回给客户端
ifconfig lo:0 $vip broadcast $vip netmask 255.255.255.255 up
route add -host $vip lo:0
#以下操作为更改arp内核参数，目的是为了让rs顺利发送mac地址给客户端
#参考文档 www.cnblogs.com/lgfeng/archive/2012/10/16/2726308.html
echo "1" > /proc/sys/net/ipv4/conf/lo/arp_ignore
echo "2" > /proc/sys/net/ipv4/conf/lo/arp_announce
echo "1" > /proc/sys/net/ipv4/conf/all/arp_ignore
echo "2" > /proc/sys/net/ipv4/conf/all/arp_announce

• 启动脚本

[root@qingyun-02 ~]# sh !$
sh /usr/local/sbin/lvs_rs.sh

• 查看路由

• 测试

[root@qingyun-01 ~]# ipvsadm -ln
IP Virtual Server version 1.2.1 (size=4096)
Prot LocalAddress:Port Scheduler Flags
  -> RemoteAddress:Port           Forward Weight ActiveConn InActConn
TCP  192.168.21.200:80 rr
  -> 192.168.21.132:80            Route   1      0          0         
  -> 192.168.21.133:80            Route   1      0          0         

18.12 keepalived + LVS

Keepalived + LVS DR

• 完整架构需要两台服务器（角色为dir）分别安装keepalived软件，目的是实现高可用，但keepalived本身也有负载均衡的功能，所以本次实验可以只安装一台keepalived

[root@qingyun-01 ~]# yum install -y keepalived

• keepalived内置了ipvsadm的功能，所以不需要再安装ipvsadm包，也不用编写和执行那个lvs_dir的脚本
• 三台机器分别为：
• dir（安装keepalived）192.168.21.130/24
• rs1 192.168.21.132/24
• rs2 192.168.21.133/24
• vip 192.168.21.200/32
• 编辑keepalived配置文件 vim /etc/keepalived/keepalived.conf //内容如下

vrrp_instance VI_1 {
    #备用服务器上为 BACKUP
    state MASTER
    #绑定vip的网卡为ens33，你的网卡和阿铭的可能不一样，这里需要你改一下
    interface ens33
    virtual_router_id 51
    #备用服务器上为90
    priority 100
    advert_int 1
    authentication {
        auth_type PASS
        auth_pass aminglinux
    }
    virtual_ipaddress {
        192.168.21.200
    }
}
virtual_server 192.168.21.200 80 {
    #(每隔10秒查询realserver状态)
    delay_loop 10
    #(lvs 算法)
    lb_algo wlc
    #(DR模式)
    lb_kind DR
    #(同一IP的连接60秒内被分配到同一台realserver)
    persistence_timeout 0
    #(用TCP协议检查realserver状态)
    protocol TCP
    real_server 192.168.21.132 80 {
        #(权重)
        weight 100
        TCP_CHECK {
        #(10秒无响应超时)
        connect_timeout 10
        nb_get_retry 3
        delay_before_retry 3
        connect_port 80
        }
    }
    real_server 192.168.21.133 80 {
        weight 100
        TCP_CHECK {
        connect_timeout 10
        nb_get_retry 3
        delay_before_retry 3
        connect_port 80
        }
     }
}

• 启动 keepalived

[root@qingyun-01 etc]# systemctl start keepalived

[root@qingyun-01 etc]# ps aux |grep keepalived
root       1615  0.0  0.1 120740  1408 ?        Ss   17:23   0:00 /usr/sbin/keepalived -D
root       1616  0.0  0.3 127480  3336 ?        S    17:23   0:00 /usr/sbin/keepalived -D
root       1617  0.0  0.2 131780  2944 ?        S    17:23   0:00 /usr/sbin/keepalived -D
root       1623  0.0  0.0 112676   976 pts/0    R+   17:25   0:00 grep --color=auto keepalived

• 执行ipvsadm -C 把之前的ipvsadm规则清空掉
• 两台rs上，依然要执行/usr/local/sbin/lvs_rs.sh脚本
  脚本在DR模式搭建小节
• keepalived有一个比较好的功能，可以在一台rs宕机时，不再把请求转发过去
• 测试

  
  [root@qingyun-01 etc]# systemctl stop keepalived
  [root@qingyun-01 etc]# ip add
  1: lo:  mtu 65536 qdisc noqueue state UNKNOWN qlen 1
  link/loopback 00:00:00:00:00:00 brd 00:00:00:00:00:00
  inet 127.0.0.1/8 scope host lo
     valid_lft forever preferred_lft forever
  inet6 ::1/128 scope host 
     valid_lft forever preferred_lft forever
  2: ens33:  mtu 1500 qdisc pfifo_fast state UP qlen 1000
  link/ether 00:0c:29:a3:53:bf brd ff:ff:ff:ff:ff:ff
  inet 192.168.21.130/24 brd 192.168.21.255 scope global ens33
     valid_lft forever preferred_lft forever
  inet6 fe80::7d:8138:e13a:91e5/64 scope link 
     valid_lft forever preferred_lft forever
  [root@qingyun-01 etc]# ipvsadm -ln
  IP Virtual Server version 1.2.1 (size=4096)
  Prot LocalAddress:Port Scheduler Flags
  -> RemoteAddress:Port           Forward Weight ActiveConn InActConn

[root@qingyun-01 etc]# systemctl start keepalived
[root@qingyun-01 etc]# ipvsadm -ln
IP Virtual Server version 1.2.1 (size=4096)
Prot LocalAddress:Port Scheduler Flags
-> RemoteAddress:Port Forward Weight ActiveConn InActConn
TCP 192.168.21.200:80 wlc
-> 192.168.21.132:80 Route 100 0 0
-> 192.168.21.133:80 Route 100 0 0

#关掉 rs2
[root@qingyun-03 ~]# systemctl stop nginx

root@qingyun-01 etc]# ipvsadm -ln
IP Virtual Server version 1.2.1 (size=4096)
Prot LocalAddress:Port Scheduler Flags
-> RemoteAddress:Port Forward Weight ActiveConn InActConn
TCP 192.168.21.200:80 wlc
-> 192.168.21.132:80 Route 100 0 0
#有间隔10s