LVS DR模式搭建、keepalived + LVS

18.11 LVS DR模式搭建

DR模式搭建-準備工做

• 三臺機器

• 分發器，也叫調度器（簡寫爲dir）
  分發器：192.168.21.130/24
  rs1:192.168.21.132/24
  rs2:192.168.21.133/24
  vip:192.168.21.200/24

• dir上編寫腳本 vim /usr/local/sbin/lvs_dr.sh //內容以下

#! /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 同等於重啓網卡，對虛擬網卡進行重置
#防止再次啓動腳本的時候，再次設置虛擬網卡的IP地址
ifdown ens33
ifup ens33
#注意這裏的網卡名字
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

• 啓動腳本

[root@qingyun-01 ~]# sh /usr/local/sbin/lvs_dr.sh
成功斷開設備 'ens33'。
鏈接已成功激活（D-Bus 活動路徑：/org/freedesktop/NetworkManager/ActiveConnection/4）

• 兩臺rs上也編寫腳本 vim /usr/local/sbin/lvs_rs.sh //內容以下

#! /bin/bash
vip=192.168.21.200
ifdown lo
ifup lo
#把vip綁定在lo上，是爲了實現rs直接把結果返回給客戶端
ifconfig lo:0 $vip broadcast $vip netmask 255.255.255.255 up
route add -host $vip lo:0
#如下操做爲更改arp內核參數，目的是爲了讓rs順利發送mac地址給客戶端
#參考文檔 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

• 啓動腳本

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

• 查看路由

• 測試

[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

• 完整架構須要兩臺服務器（角色爲dir）分別安裝keepalived軟件，目的是實現高可用，但keepalived自己也有負載均衡的功能，因此本次實驗能夠只安裝一臺keepalived

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

• keepalived內置了ipvsadm的功能，因此不須要再安裝ipvsadm包，也不用編寫和執行那個lvs_dir的腳本
• 三臺機器分別爲：
• dir（安裝keepalived）192.168.21.130/24
• rs1 192.168.21.132/24
• rs2 192.168.21.133/24
• vip 192.168.21.200/32
• 編輯keepalived配置文件 vim /etc/keepalived/keepalived.conf //內容以下

vrrp_instance VI_1 {
    #備用服務器上爲 BACKUP
    state MASTER
    #綁定vip的網卡爲ens33，你的網卡和阿銘的可能不同，這裏須要你改一下
    interface ens33
    virtual_router_id 51
    #備用服務器上爲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秒查詢realserver狀態)
    delay_loop 10
    #(lvs 算法)
    lb_algo wlc
    #(DR模式)
    lb_kind DR
    #(同一IP的鏈接60秒內被分配到同一臺realserver)
    persistence_timeout 0
    #(用TCP協議檢查realserver狀態)
    protocol TCP
    real_server 192.168.21.132 80 {
        #(權重)
        weight 100
        TCP_CHECK {
        #(10秒無響應超時)
        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
        }
     }
}

• 啓動 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

• 執行ipvsadm -C 把以前的ipvsadm規則清空掉
• 兩臺rs上，依然要執行/usr/local/sbin/lvs_rs.sh腳本
  腳本在DR模式搭建小節
• keepalived有一個比較好的功能，能夠在一臺rs宕機時，再也不把請求轉發過去
• 測試

  [root@qingyun-01 etc]# systemctl stop keepalived
  [root@qingyun-01 etc]# ip add
  1: lo: <LOOPBACK,UP,LOWER_UP> 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: <BROADCAST,MULTICAST,UP,LOWER_UP> 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

#關掉 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
#有間隔10s