LVS+Keepalived實現高可用集羣

時間 2021-08-14

標籤 php html linux web 算法 bash 服務器 app 負載均衡 ide 欄目負載均衡简体版

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操做系統平臺：CentOS5.2
軟件：LVS+keepalived

LVS+Keepalived 介紹

LVS

LVS是Linux Virtual Server的簡寫，意即Linux虛擬服務器，是一個虛擬的服務器集羣系統。本項目在1998年5月由章文嵩博士成立，是中國國內最先出現的自由軟件項目之一。目前有三種IP負載均衡技術（VS/NAT、VS/TUN和VS/DR）；
十種調度算法（rrr|wrr|lc|wlc|lblc|lblcr|dh|sh|sed|nq）。
Keepalvied
Keepalived在這裏主要用做RealServer的健康狀態檢查以及LoadBalance主機和BackUP主機之間failover的實現php

IP配置信息:html

LVS-DR-Master 192.168.2.166
LVS-DR-BACKUP 192.168.2.167
LVS-DR-VIP 192.168.2.170
WEB1-Realserver 192.168.2.171
WEB2-Realserver 192.168.2.172
GateWay 192.168.2.253
安裝LVS和Keepalvied軟件包

1. 下載相關軟件包
#mkdir /usr/local/src/lvs
#cd /usr/local/src/lvs
#wget
http://www.linuxvirtualserver.org/software/kernel-2.6/ipvsadm-1.24.tar.gz
#wget
http://www.keepalived.org/software/keepalived-1.1.15.tar.gz

2. 安裝LVS和Keepalived
#lsmod |grep ip_vs
#uname -r
2.6.18-53.el5PAE
#ln -s /usr/src/kernels/2.6.18-53.el5PAE-i686/ /usr/src/linux
#tar zxvf ipvsadm-1.24.tar.gz
#cd ipvsadm-1.24
#make && make install
#find / -name ipvsadm # 查看ipvsadm的位置
#tar zxvf keepalived-1.1.15.tar.gz
#cd keepalived-1.1.15
#./configure && make && make install
#find / -name keepalived # 查看keepalived位置
#cp /usr/local/etc/rc.d/init.d/keepalived /etc/rc.d/init.d/
#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/
#service keepalived start|stop    #作成系統啓動服務方便管理.
四. 配置LVS實現負載均衡

  1． LVS-DR，配置LVS腳本實現負載均衡

vi /usr/local/sbin/lvs-dr.sh

#!/bin/bash
# description: start LVS of DirectorServer
#Written by :NetSeek
http://www.linuxtone.org
GW=192.168.2.253

# website director vip.
WEB_VIP=192.168.2.170
WEB_RIP1=192.168.2.171
WEB_RIP2=192.168.2.172
. /etc/rc.d/init.d/functions

logger $0 called with $1

case "$1" in

start)
      # Clear all iptables rules.
      /sbin/iptables -F
      # Reset iptables counters.
      /sbin/iptables -Z
      # Clear all ipvsadm rules/services.
      /sbin/ipvsadm -C

#set lvs vip for dr
      /sbin/ipvsadm --set 30 5 60
      /sbin/ifconfig eth0:0 $WEB_VIP broadcast $WEB_VIP netmask 255.255.255.255 up
      /sbin/route add -host $WEB_VIP dev eth0:0
      /sbin/ipvsadm -A -t $WEB_VIP:80 -s wrr -p 3
      /sbin/ipvsadm -a -t $WEB_VIP:80 -r $WEB_RIP1:80 -g -w 1
      /sbin/ipvsadm -a -t $WEB_VIP:80 -r $WEB_RIP2:80 -g -w 1
      touch /var/lock/subsys/ipvsadm >/dev/null 2>&1

      # set Arp
      /sbin/arping -I eth0 -c 5 -s $WEB_VIP $GW >/dev/null 2>&1
   ;;
stop)
      /sbin/ipvsadm -C
      /sbin/ipvsadm -Z
      ifconfig eth0:0 down
      route del $WEB_VIP  >/dev/null 2>&1
      rm -rf /var/lock/subsys/ipvsadm >/dev/null 2>&1
      /sbin/arping -I eth0 -c 5 -s $WEB_VIP $GW
      echo "ipvsadm stoped"
   ;;

status)

      if [ ! -e /var/lock/subsys/ipvsadm ];then
            echo "ipvsadm is stoped"
            exit 1
      else
            ipvsadm -ln
            echo "..........ipvsadm is OK."
      fi
   ;;

*)
      echo "Usage: $0 {start|stop|status}"
      exit 1
esac

exit 0
2．配置Realserver腳本.

#!/bin/bash
# Written by NetSeek
# description: Config realserver lo and apply noarp
WEB_VIP=192.168.2.170

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

case "$1" in
start)
   ifconfig lo:0 $WEB_VIP netmask 255.255.255.255 broadcast $WEB_VIP
   /sbin/route add -host $WEB_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 $WEB_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"
   ;;
status)
      # Status of LVS-DR real server.
      islothere=`/sbin/ifconfig lo:0 | grep $WEB_VIP`
      isrothere=`netstat -rn | grep "lo:0" | grep $web_VIP`
      if [ ! "$islothere" -o ! "isrothere" ];then
         # Either the route or the lo:0 device
         # not found.
         echo "LVS-DR real server Stopped."
      else
         echo "LVS-DR Running."
      fi
;;
*)
      # Invalid entry.
      echo "$0: Usage: $0 {start|status|stop}"
      exit 1
;;
esac
exit 0

附上realserver機上的/etc/sysctl.conf：

# Kernel sysctl configuration file for Red Hat Linux
#
# For binary values, 0 is disabled, 1 is enabled.  See sysctl(8) and
# sysctl.conf(5) for more details.
# Controls IP packet forwarding
net.ipv4.ip_forward = 1
# Controls source route verification
net.ipv4.conf.default.rp_filter = 1
# Do not accept source routing
net.ipv4.conf.default.accept_source_route = 0
# Controls the System Request debugging functionality of the kernel
kernel.sysrq = 0
# Controls whether core dumps will append the PID to the core filename.
# Useful for debugging multi-threaded applications.
kernel.core_uses_pid = 1
net.ipv4.conf.lo.arp_ignore = 1
net.ipv4.conf.lo.arp_announce = 2
net.ipv4.conf.all.arp_ignore = 1
net.ipv4.conf.all.arp_announce = 2
或者採用secondary ip address方式配置
# vi /etc/sysctl.conf

添加如下內容如上所示：

net.ipv4.conf.lo.arp_ignore = 1
net.ipv4.conf.lo.arp_announce = 2
net.ipv4.conf.all.arp_ignore = 1
net.ipv4.conf.all.arp_announce = 2
#sysctl –p
#ip addr add 61.164.122.8/32 dev lo
#ip add list 查看是否綁定
3. 啓動lvs-dr腳本和realserver啓本，在DR上能夠查看LVS當前狀態:
#watch ipvsadm –ln

五．利用Keepalvied實現負載均衡和和高可用性

1.配置在主負載均衡服務器上配置keepalived.conf
#vi /etc/keepalived/keepalived.conf (主調度器)
! Configuration File for keepalived
global_defs {
notification_email {

acassen@firewall.loc

failover@firewall.loc

sysadmin@firewall.loc
}
notification_email_from
Alexandre.Cassen@firewall.loc
smtp_server 127.0.0.1
smtp_connect_timeout 30
router_id LVS_DEVEL
}
vrrp_instance VI_1 {
state MASTER
interface eth0
virtual_router_id 51
priority 100
advert_int 1
authentication {
      auth_type PASS
      auth_pass 1111
}
virtual_ipaddress {
      192.168.2.170
}
}
virtual_server 192.168.2.170 80 {
delay_loop 6
lb_algo wrr
lb_kind DR
persistence_timeout 60
protocol TCP

real_server 192.168.2.171 80 {
      weight 3
      TCP_CHECK {
      connect_timeout 10
      nb_get_retry 3
      delay_before_retry 3
      connect_port 80
}
}
real_server 192.168.2.172 80 {
      weight 3
      TCP_CHECK {
      connect_timeout 10
      nb_get_retry 3
      delay_before_retry 3
      connect_port 80
      }
   }
}

在備用調度器上：
#vi /etc/keepalived/keepalived.conf (備用調度器)
! Configuration File for keepalived
global_defs {
notification_email {

acassen@firewall.loc

failover@firewall.loc

sysadmin@firewall.loc
}
notification_email_from
Alexandre.Cassen@firewall.loc
smtp_server 127.0.0.1
smtp_connect_timeout 30
router_id LVS_DEVEL
}
vrrp_instance VI_1 {
state BACKUP
interface eth0
virtual_router_id 51
priority 99
advert_int 1
authentication {
      auth_type PASS
      auth_pass 1111
}
virtual_ipaddress {
      192.168.2.170
}
}
virtual_server 192.168.2.170 80 {
delay_loop 6
lb_algo wrr
lb_kind DR
persistence_timeout 60
protocol TCP

real_server 192.168.2.171 80 {
      weight 3
      TCP_CHECK {
      connect_timeout 10
      nb_get_retry 3
      delay_before_retry 3
      connect_port 80
}
}
real_server 192.168.2.172 80 {
      weight 3
      TCP_CHECK {
      connect_timeout 10
      nb_get_retry 3
      delay_before_retry 3
      connect_port 80
      }
   }
}

2. BACKUP服務器同上配置，先安裝lvs再按裝keepalived,仍後配置/etc/keepalived/keepalived.conf，只需將紅色標示的部分改一下便可.
3. vi /etc/rc.local
#/usr/local/sbin/lvs-dr.sh  將lvs-dr.sh這個腳本註釋掉。
#/usr/local/sbin/lvs-dr.sh stop 中止lvs-dr腳本
#/etc/init.d/keepalived start  啓動keepalived 服務，keepalived就能利用keepalived.conf 配
置文件，實現負載均衡和高可用.
4. 查看lvs服務是否正常

#watch ipvsadm –ln
IP Virtual Server version 1.2.1 (size=4096)
Prot LocalAddressort Scheduler Flags
  -> RemoteAddressort          Forward Weight ActiveConn InActConn
TCP  61.164.122.8:80 wrr persistent 60
  -> 61.164.122.10:80          Route 3    0       0
  -> 61.164.122.9:80          Route 3    0       0
複製代碼
#tail –f /var/log/message  監聽日誌，查看狀態，測試LVS負載均衡及高可用性是否有效。
5．停Master服務器的keepalived服務，查看BAKCUP服務器是否能正常接管服務。
四．相關參考
1．LVS 基礎知識彙總
LVS的算法介紹
http://www.linuxtone.org/viewthread.php?tid=69
學習LVS的三種轉發模式
http://www.linuxtone.org/viewthread.php?tid=77
LVS中的IP負載均衡技術
http://www.linuxtone.org/viewthread.php?tid=68
更多的請到
http://www.linuxtone.org
負載均衡版查看
Keepalived 相關參考資料。

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