LVS+keepalived

四臺centos5.5

VIP 192.168.0.82
lvs 192.168.0.81 192.168.0.74
web 192.168.0.72 192.168.0.73


LVS服務器(DR模式，所有IP都在內網)

ln -s /usr/src/kernels/2.6.18-53.e15-i686/ /usr/src/linux
#如果/usr/src/kernels/目錄空先安裝kernel-devel
#yum install  kernel-devel
yum install ipvsadm
ipvsadm
lsmod |grep ip_vs

echo "1" > /proc/sys/net/ipv4/ip_forward

#/bin/bash
VIP=192.168.0.82
WEB1=192.168.0.72
WEB2=192.168.0.73

case "$1" in
start)

/sbin/ifconfig eth0:0 $VIP broadcast $VIP netmask 255.255.255.255 up
/sbin/route add -host $VIP dev eth0:0
/sbin/ipvsadm -C
/sbin/ipvsadm -A -t $VIP:80 -s rr
/sbin/ipvsadm -a -t $VIP:80 -r $WEB1 -g
/sbin/ipvsadm -a -t $VIP:80 -r $WEB2 -g
touch /var/lock/subsys/ipvsadm >/dev/null 2>&1
echo "lvs status-------------------[OK]"
;;
stop)
/sbin/ipvsadm -C
/sbin/ifconfig eth0:0 down
route del $VIP
rm -rf /var/lock/subsys/ipvsadm >/dev/null 2>&1
echo "lvs stop"
;;
status)
if [ ! -e /var/lock/subsys/ipvsadm ];then
    echo "lvs stop"
    exit 1
else
    echo "lvs status-------------------[OK]"
fi
;;
*)
echo "Usage: $0 {start|stop|status}"
exit 1
;;
esac




WEB服務器(兩臺一致)

#!/bin/bash
#description:start realserver
#chkconfig
VIP=192.168.0.82
/etc/rc.d/init.d/functions
case "$1" in
start)
echo " start LVS of REALServer"
/sbin/ifconfig lo:0 $VIP1 broadcast $VIP1 netmask 255.255.255.255 up
/sbin/route add -host $VIP1 dev lo:0
echo "1" >/proc/sys/net/ipv4/ip_forward
echo "1" >/proc/sys/net/ipv4/conf/eth0/arp_ignore
echo "2" >/proc/sys/net/ipv4/conf/eth0/arp_announce
echo "1" >/proc/sys/net/ipv4/conf/all/arp_ignore
echo "2" >/proc/sys/net/ipv4/conf/all/arp_announce
;;
stop)
/sbin/ifconfig lo:0 down
echo "close LVS Directorserver"
echo "0" >/proc/sys/net/ipv4/ip_forward
echo "0" >/proc/sys/net/ipv4/conf/eth0/arp_ignore
echo "0" >/proc/sys/net/ipv4/conf/eth0/arp_announce
echo "0" >/proc/sys/net/ipv4/conf/all/arp_ignore
echo "0" >/proc/sys/net/ipv4/conf/all/arp_announce
;;
*)
echo "Usage: $0 {start|stop}"
exit 1
esac



編譯 keepalived-1.1.17(版本不可過高)

yum install libnl-devel
./configure
make
make install

cp /usr/local/etc/rc.d/init.d/keepalived /etc/rc.d/init.d/   #設置爲service方式啓動
cp /usr/local/etc/sysconfig/keepalived /etc/sysconfig/
mkdir /etc/keepalived
cp /usr/local/etc/keepalived/keepalived.conf /etc/keepalived/
cp /usr/local/sbin/keepalived /usr/sbin/

/etc/init.d/keepalived start   #啓動keepalived

vi /etc/rc.local  #添加爲開機自啓動
/usr/local/sbin/keepalived -D -f /etc/keepalived/keepalived.conf

# sed -i 's#net.ipv4.ip_forward = 0#net.ipv4.ip_forward = 1#' /etc/sysctl.conf  #開啓內核轉發功能
# sysctl -p    #查看是否開啓內核轉發

mv /etc/keepalived/keepalived.conf /etc/keepalived/keepalived.conf_bak  #備份原始配置文件

vi /etc/keepalived/keepalived.conf

========================================================


!Configuration File for keepalived

global_defs {
    #notification_email {
    #    [email protected]    #填寫自己的郵箱出現故障接收報警郵件用
    #}
    #notification_email_from [email protected]
    #smtp_server 127.0.0.1
    #smtp_connect_timeout 30
    router_id LVS_01 #備份服務器改爲LVS_02
}

vrrp_instance VI_1 {
    state MASTER #備份服務器上MASTER爲BACKUP
    interface eth0
    #lvs_sync_daemon_inteface eth1
    virtual_router_id 51
    priority 100 #備份服務上優先級要低於100，如改爲90
    advert_int 1
    authentication {
        auth_type PASS
        auth_pass 1111
    }
    virtual_ipaddress {
        192.168.0.82   #這裏填寫VIP地址，也可添加多個VIP
    }
}

virtual_server 192.168.0.82 80 {   #這裏填寫VIP地址
    delay_loop 6
    lb_algo rr
    lb_kind DR
    #nat_mask 255.255.255.0
    persistence_timeout 50
    protocol TCP
    real_server 192.168.0.72 80 { #這裏是真實服務器的IP
        weight 1
        TCP_CHECK {
            connect_timeout 3
            nb_get_retry 3
            delay_before_retry 3
            connect_port 80
        }
    }
    real_server 192.168.0.73 80 { #這裏是第二臺真實服務器的IP
        weight 2
        TCP_CHECK {
            connect_timeout 3
            nb_get_retry 3
            delay_before_retry 3
            connect_port 80
        }
    }
}

========================================================





keepalived.conf 文件詳解


安裝完成之後，生成的配置文件放置於:/usr/local/keepalived/etc/keepalived/keepalived.conf
官方提供了不少模板性的配置文件：/usr/local/keepalived/etc/keepalived/samples
建議將配置文件放置於: /etc/keepalived/keepalived.conf
如果運用不指定配置文件，他可以直接調用/etc/keepalived/keepalived.conf中的配置文件

接下來，詳細說明配置文件中的各項含義：

#全局定義塊，以下模塊不可省略，必須存在。
global_defs {
notification_email {
email #如有故障，發郵件報警的地址，一般不採用，可以隨意填寫
}

notification_email_from email
smtp_server host
smtp_connect_timeout num #郵件服務鏈接超時的最長時間
lvs_id string #Lvs負載均衡器標識，在一個網絡裏面，請保持他是唯一性。

}

#VRRP實例定義塊

vrrp_sync_group string {  #確定失敗切換（FailOver）包含的路由實例個數。即在有2個負載均衡器的場景，一旦某個負載均衡器失效
group {
string #備用的負載均衡的服務器名
string
}

vrrp_instance string { #前面定義的後備的負載均衡的服務器名

state MASTER|BACKUP #只有MASTER和BACKUP兩種狀態，都必須保持大寫。

interface string #進行通信的端口，如eth0,eth1

mcast_src_ip @IP #真實的IP地址

lvs_sync_daemon_interface string #負載均衡器之間的監控接口。如果採用DR模式，可以保持和通信端口一致。

virtual_router_id num #這個標識是同一個vrrp實例使用唯一的標識。即同一個vrrp_stance,MASTER和BACKUP的virtual_router_id是一致的，同時在整個vrrp內是唯一的。

priority num #權重，數值越大，權重越大，Master大於Slave。

advert_int num #Master和Slave負載均衡器之間同步檢查的時間間隔，單位：秒

smtp_alert

authentication { #Master和Slave之間認證的方式

auth_type PASS|AH

auth_pass string #認證的祕密

}

virtual_ipaddress { # Block limited to 20 IP addresses

IP
IP
IP

}

virtual_ipaddress_excluded { # Unlimited IP addresses number

IP
IP
IP

}

#虛擬服務器定義塊

virtual_server (@IP PORT)|(fwmark num) { #上面定義的virtual_ipaddress，需要添加端口

delay_loop num #服務健康檢查週期，單位：秒

lb_algo rr|wrr|lc|wlc|sh|dh|lblc #負載均衡的調度算法方式，一般使用rr或者wlc。

lb_kind NAT|DR|TUN #負載均衡轉發規則，一般採用DR

(nat_mask @IP) #地址掩碼，可不填

persistence_timeout num #會話保持時間，單位：秒。如果是動態服務，建議開啓。

persistence_granularity @IP

virtualhost string

protocol TCP|UDP #通信協議，有

sorry_server @IP PORT

real_server @IP PORT { #真實IP地址

weight num #權重值，數值越大，權重越高，分發的可能越大。

TCP_CHECK {

connect_port num #檢查端口

connect_timeout num #檢查超時時間

}

}

real_server @IP PORT {

weight num

MISC_CHECK {

misc_path /path_to_script/script.sh

(or misc_path “/path_to_script/script.sh ”)

}

}

real_server @IP PORT {

weight num

HTTP_GET|SSL_GET {

url { # You can add multiple url block

path alphanum

digest alphanum

}

connect_port num

connect_timeout num

nb_get_retry num

delay_before_retry num

}

}

}

keepalived 實例

Master 服務器

#guration File for keepalived (Master Server)

#writed by eric.w.t 2011/04/12

###################################
#   global define
###################################

global_defs {
notification_email {
[email protected]
}
notification_email_from [email protected]
smtp_server 127.0.0.1
smtp_connect_timeout 30
router_id LVS_DEVEL
}

####################################
#   vrrp define
####################################

vrrp_sync_group VGM {
group {
VI_1
}
}

vrrp_instance VI_1 {

state MASTER
interface eth0
virtual_router_id 110
priority 100
advert_int 1
virtual_ipaddress {
10.249.0.208
}
}

#####################################
#   virtual machine setting
#####################################

virtual_server 10.249.0.208 80 {
delay_loop 6
lb_algo rr
lb_kind NAT
nat_mask 255.255.255.0
protocol TCP
persistence_timeout 20

real_server 10.249.0.254 80 {

weight 10
TCP_CHECK {
connect_timeout 3
nb_get_retry 3
delay_before_retry 3
connect_port 80
}
}

}

Slave 服務器配置

#guration File for keepalived (Slave Server)

#writed by eric.w.t 2011/04/12

###################################
#   global define
###################################

global_defs {
notification_email {
[email protected]
}
notification_email_from [email protected]
smtp_server 127.0.0.1
smtp_connect_timeout 30
router_id LVS_DEVEL
}

####################################
#   vrrp define
####################################

vrrp_sync_group VGM {
group {
VI_1
}
}

vrrp_instance VI_1 {

state SLAVE
interface eth0
virtual_router_id 110
priority 99
advert_int 1
virtual_ipaddress {
10.249.0.208
}
}

#####################################
#   virtual machine setting
#####################################

virtual_server 10.249.0.208 80 {
delay_loop 6
lb_algo rr
lb_kind NAT
nat_mask 255.255.255.0
protocol TCP
persistence_timeout 20

real_server 10.249.0.254 80 {

weight 10
TCP_CHECK {
connect_timeout 3
nb_get_retry 3
delay_before_retry 3
connect_port 80
}
}

}

參考文檔 ：

http://www.keepalived.org/documentation.html


#調用檢測腳本

vrrp_script check_run {

     script "/root/keepalived_check_mysql.sh"

     interval 5

}