LVS+keepalived負載均衡實戰

1、爲何要使 用負載均衡技術？

一、系統高可用性

二、  系統可擴展性

三、  負載均衡能力

LVS+keepalived能很好的實現以上的要求，LVS提 供負載均衡，keepalived提供健康檢查，故障轉移，提升系統的可用性！採用這樣的架構之後 很容易對現有系統進行擴展，只要在後端添加或者減小realserver，只要更改lvs的 配置文件，並能實現無縫配置變動！

 

2、LVS+Keepalived介紹

一、  LVS

LVS是一個開源的軟件，能夠實現LINUX平臺下的簡單負載均衡。LVS是Linux Virtual Server的縮寫，意思是Linux虛擬服務器。目前有三種IP負 載均衡技術（VS/NAT、VS/TUN和VS/DR）；八種調度算法（rr,wrr,lc,wlc,lblc,lblcr,dh,sh）。

二、  keepalived

Keepalived 是運行在lvs 之上，它的主要功能是實現真實機的故障隔離及負載均衡器間的失敗 切換，提升系統的可用性

 

3、LVS+keepalived負載均衡架構圖

  

 

4、LVS+keepalived的安裝和配置

1.         配置環境

              System OS：CentOS release 5.4

              Software：ipvsadm-1.24.tar.gz, keepalived-1.1.19.tar.gz

安裝lvs

分別在backup lvs和master lvs上安裝

wget http://www.linuxvirtualserver.org/software/kernel-2.6/ipvsadm-1.24.tar.gz

ln -s /usr/src/kernels/2.6.18-164.el5-i686/ /usr/src/linux

tar zxvf ipvsadm-1.24.tar.gz

cd ipvsadm-1.24

make && make install

 安裝keepalived

分別在backup lvs和master lvs上安裝

wget http://www.keepalived.org/software/keepalived-1.1.19.tar.gz
tar zxvf keepalived-1.1.19.tar.gz
cd keepalived-1.1.19
./configure --prefix=/usr/local/keepalived
make 
make install
cp /usr/local/keepalived/sbin/keepalived /usr/sbin/
cp /usr/local/keepalived/etc/sysconfig/keepalived /etc/sysconfig/
cp /usr/local/keepalived/etc/rc.d/init.d/keepalived /etc/init.d/
mkdir /etc/keepalived

配置keepadlived

LVS-Master的配置文件以下

[root@linux5 ~]# cat /etc/keepalived/keepalived.conf

global_defs {

notification_email {

               jimo291@gmail.com    #email 通知

        }

        notification_email_from jimo291@gmail.com

        smtp_server 127.0.0.1

        smtp_connect_timeout 30

        router_id LVS1          # 設置lvs的id，在一個網絡內應該是惟一的

}

vrrp_sync_group test {           #設置vrrp組

group {

        loadbalance

}

}

 

vrrp_instance loadbalance {

        state MASTER       #設置lvs的狀態，報錯MASTER和BACKUP兩種，必須大寫

        interface eth0     #設置對外服務的接口

        lvs_sync_daemon_inteface eth0   #設置lvs監聽的接口

        virtual_router_id 51                     #設置虛擬路由表示

        priority 180            #設置優先級，數值越大，優先級越高

        advert_int 5           #設置同步時間間隔

authentication {                    #設置驗證類型和密碼

        auth_type PASS

        auth_pass 1111

}

virtual_ipaddress {                #設置lvs vip

        192.168.1.115

}

}

 

virtual_server 192.168.1.115 80 {

        delay_loop 6          #健康檢查時間間隔

        lb_algo rr               #負載均衡調度算法

        lb_kind DR            #負載均衡轉發規則

        #persistence_timeout 20  #設置會話保持時間，對bbs等頗有用

        protocol TCP                #協議

        real_server 192.168.1.105 80 {

        weight 3                #設置權重

        TCP_CHECK {

        connect_timeout 3

        nb_get_retry 3

        delay_before_retry 3

        connect_port 80

}

}

        real_server 192.168.1.103 80 {

        weight 3

        TCP_CHECK {

        connect_timeout 3

        nb_get_retry 3

        delay_before_retry 3

        connect_port 80

}

}

        real_server 192.168.1.104 80 {

        weight 3

        TCP_CHECK {

        connect_timeout 3

        nb_get_retry 3

        delay_before_retry 3

        connect_port 80

}

}

}

LVS-backup的配置文件以下

global_defs {

notification_email {

               jimo291@gmail.com

        }

        notification_email_from jimo291@gmail.com

        smtp_server 127.0.0.1

        smtp_connect_timeout 30

        router_id LVS2

}

vrrp_sync_group test {

group {

        loadbalance

}

}

 

vrrp_instance loadbalance {

        state BACKUP

        interface eth0

        lvs_sync_daemon_inteface eth0

        virtual_router_id 51

        priority 150

        advert_int 5

authentication {

        auth_type PASS

        auth_pass 1111

}

virtual_ipaddress {

        192.168.1.115

}

}

 

virtual_server 192.168.1.115 80 {

        delay_loop 6

        lb_algo rr

        lb_kind DR

        #persistence_timeout 20

        protocol TCP

        real_server 192.168.1.105 80 {

        weight 3

        TCP_CHECK {

        connect_timeout 3

        nb_get_retry 3

        delay_before_retry 3

        connect_port 80

}

}

        real_server 192.168.1.103 80 {

        weight 3

        TCP_CHECK {

        connect_timeout 3

        nb_get_retry 3

        delay_before_retry 3

        connect_port 80

}

}

        real_server 192.168.1.104 80 {

        weight 3

        TCP_CHECK {

        connect_timeout 3

        nb_get_retry 3

        delay_before_retry 3

        connect_port 80

}

}

}

  Realserver的配置

三臺客戶端的腳本都同樣！

cat /etc/rc.d/init.d/realserver.sh

#!/bin/bash

# description: Config realserver lo and apply noarp

 

SNS_VIP=192.168.1.115

 

/etc/rc.d/init.d/functions

 

case "$1" in

start)

       ifconfig lo:0 $SNS_VIP netmask 255.255.255.255 broadcast $SNS_VIP

       /sbin/route add -host $SNS_VIP dev lo:0

       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

       sysctl -p >/dev/null 2>&1

       echo "RealServer Start OK"

 

       ;;

stop)

       ifconfig lo:0 down

       route del $SNS_VIP >/dev/null 2>&1

       echo "0" >/proc/sys/net/ipv4/conf/lo/arp_ignore

       echo "0" >/proc/sys/net/ipv4/conf/lo/arp_announce

       echo "0" >/proc/sys/net/ipv4/conf/all/arp_ignore

       echo "0" >/proc/sys/net/ipv4/conf/all/arp_announce

       echo "RealServer Stoped"

       ;;

*)

       echo "Usage: $0 {start|stop}"

       exit 1

esac

 

exit 0