RHEL 5.4下部署LVS(DR)+keepalived实现高性能高可用负载均衡

迈不过友情╰ 2022-04-22 23:44 56阅读 0赞

**一、简介**

LVS是Linux Virtual Server的简写，意即Linux虚拟服务器，是一个虚拟的服务器集群系统。本项目在1998年5月由章文嵩博士成立，是中国国内最早出现的自由软件项目之一。

目前有三种IP负载均衡技术（VS/NAT、VS/TUN和VS/DR）；十种调度算法（rr|wrr|lc|wlc|lblc|lblcr|dh|sh|sed|nq）。

Keepalived在这里主要用作RealServer的健康状态检查以及LoadBalance主机和BackUP主机之间failover的实现。

LVS+Keepalived能实现的功能：利用LVS控制器主备模式避免单点故障以及自动删除故障WEB服务器结点并当它恢复后再自动添加到群集中。

**拓扑图：**

![2012081715214381.jpg][]

**二、系统环境**

系统平台：RHEL 5.4

LVS版本：ipvsadm-1.24

keepalived版本：keepalived-1.1.15

**三、安装**

1、在两台LVS Server上安装lvs、keepalived软件（LVS\_MASTER & LVS\_BACKUP）  
**lvs install -------------**

\[root@LVS-MASTER ~\]\# wget http://www.linuxvirtualserver.org/software/kernel-2.6/ipvsadm-1.24.tar.gz

\[root@LVS-MASTER ~\]\# ln -s /usr/src/kernels/2.6.18-194.el5-i686//usr/src/linux/

\[root@LVS-MASTER ~\]\# tar zxvf ipvsadm-1.24.tar.gz

\[root@LVS-MASTER ~\]\# cd ipvsadm-1.24

\[root@LVS-MASTER ipvsadm-1.24\]\# make && make install

**Keepalived install\-------------**

\[root@LVS-MASTER ~\]\# wget http://www.keepalived.org/software/keepalived-1.1.15.tar.gz

\[root@LVS-MASTER ~\]\# tar zxvf keepalived-1.1.15.tar.gz

\[root@LVS-MASTER ~\]\# cd keepalived-1.1.15

\[root@LVS-MASTER keepalived-1.1.15\]\# ./configure && make && make install

\#\#\#\#\#\#\#\#\# 将keepalived做成启动服务，方便管理\#\#\#\#\#\#\#\#\#\#

\[root@LVS-MASTER ~\]\# cp /usr/local/etc/rc.d/init.d/keepalived /etc/init.d/

\[root@LVS-MASTER ~\]\# cp /usr/local/etc/sysconfig/keepalived /etc/sysconfig/

\[root@LVS-MASTER ~\]\# mkdir /etc/keepalived/

\[root@LVS-MASTER ~\]\# cp /usr/local/etc/keepalived/keepalived.conf /etc/keepalived/

\[root@LVS-MASTER ~\]\# cp /usr/local/sbin/keepalived /usr/sbin/

\[root@LVS-MASTER ~\]\# service keepalived start | stop

2、keepalived的配置

\#\#\#\#\#\#\#\#\#\#\#\#\#\#\#\#\#\#\#  MASTER \#\#\#\#\#\#\#\#\#\#\#\#\#\#\#\#\#\#\#

! Configuration File for keepalived
    
    global_defs {
       notification_email {
         root@linux.tang.chao               #设置报警邮件地址，可以设置多个，每行一个。
         mchina_tang@qq.com                 #需开启本机的sendmail服务
       }
       notification_email_from keepalived@localhost         #设置邮件的发送地址
       smtp_server 127.0.0.1                                #设置smtp server地址
       smtp_connect_timeout 30                              #设置连接smtp server的超时时间
       router_id LVS_DEVEL                                  #表示运行keepalived服务器的一个标识。发邮件时显示在邮件主题的信息
    }
    
    vrrp_instance VI_1 {
        state MASTER              #指定keepalived的角色，MASTER表示此主机是主服务器，BACKUP表示此主机是备用服务器
        interface eth0            #指定HA监测网络的接口
        virtual_router_id 51      #虚拟路由标识，这个标识是一个数字，同一个vrrp实例使用唯一的标识。即同一vrrp_instance下，MASTER和BACKUP必须是一致的
        priority 100              #定义优先级，数字越大，优先级越高，在同一个vrrp_instance下，MASTER的优先级必须大于BACKUP的优先级
        advert_int 1              #设定MASTER与BACKUP负载均衡器之间同步检查的时间间隔，单位是秒
        authentication {          #设置验证类型和密码
            auth_type PASS        #设置验证类型，主要有PASS和AH两种
            auth_pass 1111        #设置验证密码，在同一个vrrp_instance下，MASTER与BACKUP必须使用相同的密码才能正常通信
        }
        virtual_ipaddress {       #设置虚拟IP地址，可以设置多个虚拟IP地址，每行一个
            10.0.0.148
        }
    }
    
    virtual_server 10.0.0.148 80 {      #设置虚拟服务器，需要指定虚拟IP地址和服务端口，IP与端口之间用空格隔开
        delay_loop 6                    #设置运行情况检查时间，单位是秒
        lb_algo rr                      #设置负载调度算法，这里设置为rr，即轮询算法
        lb_kind DR                      #设置LVS实现负载均衡的机制，有NAT、TUN、DR三个模式可选
        persistence_timeout 50          #会话保持时间，单位是秒。这个选项对动态网页是非常有用的，为集群系统中的session共享提供了一个很好的解决方案。 #有了这个会话保持功能，用户的请求会被一直分发到某个服务节点，直到超过这个会话的保持时间。 #需要注意的是，这个会话保持时间是最大无响应超时时间，也就是说，用户在操作动态页面时，如果50秒内没有执行任何操作， #那么接下来的操作会被分发到另外的节点，但是如果用户一直在操作动态页面，则不受50秒的时间限制
        protocol TCP                   #指定转发协议类型，有TCP和UDP两种
    
        real_server 10.0.0.137 80 {     #配置服务节点1，需要指定real server的真实IP地址和端口，IP与端口之间用空格隔开
            weight 3                   #配置服务节点的权值，权值大小用数字表示，数字越大，权值越高，设置权值大小可以为不同性能的服务器 #分配不同的负载，可以为性能高的服务器设置较高的权值，而为性能较低的服务器设置相对较低的权值，这样才能合理地利用和分配系统资源
            TCP_CHECK {                 #realserver的状态检测设置部分，单位是秒
                connect_timeout 10      #表示10秒无响应超时
                nb_get_retry 3         #表示重试次数
                delay_before_retry 3    #表示重试间隔
                connect_port 80
            }
        }
        real_server 10.0.0.139 80 {
            weight 3
            TCP_CHECK {
                connect_timeout 10
                nb_get_retry 3
                delay_before_retry 3
                connect_port 80
            }
        }
    }

\#\#\#\#\#\#\#\#\#\#\#\#\#\#\#\#\#\#\#\# BACKUP \#\#\#\#\#\#\#\#\#\#\#\#\#\#\#\#\#\#\#

! Configuration File for keepalived
    
    global_defs {
       notification_email {
         root@linux.tang.chao
         mchina_tang@qq.com
       }
       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 {
            10.0.0.148
        }
    }
    
    virtual_server 10.0.0.148 80 {
        delay_loop 6
        lb_algo rr
        lb_kind DR
        persistence_timeout 50
        protocol TCP
    
        real_server 10.0.0.137 80 {
            weight 3
            TCP_CHECK {
                connect_timeout 10
                nb_get_retry 3
                delay_before_retry 3
                connect_port 80
            }
        }
        real_server 10.0.0.139 80 {
            weight 3
            TCP_CHECK {
                connect_timeout 10
                nb_get_retry 3
                delay_before_retry 3
                connect_port 80
            }
        }
    }

3、在两台Web Server上执行realserver.sh脚本，为lo:0绑定VIP地址10.0.0.148、抑制ARP广播。

\[root@web1 ~\]\# cat realserver.sh

#!/bin/bash
    #description: Config realserver
    
    VIP=10.0.0.148
     
    /etc/rc.d/init.d/functions
     
    case "$1" in
    start)
           /sbin/ifconfig lo:0 $VIP netmask 255.255.255.255 broadcast $VIP
           /sbin/route add -host $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)
           /sbin/ifconfig lo:0 down
           /sbin/route del $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

\[root@web1 ~\]\# sh realserver.sh start

4、分别在LVS-MASTER、LVS-BACKUP上执行service keepalived start启动keepalived就可实现负载均衡及高可用集群了；

\[root@LVS-MASTER keepalived\]\# service keepalived start

\[root@LVS-MASTER keepalived\]\# ipvsadm -L  
IP Virtual Server version 1.2.1 (size=4096)  
Prot LocalAddress:Port Scheduler Flags  
  -> RemoteAddress:Port           Forward Weight ActiveConn InActConn  
TCP  10.0.0.148:http rr persistent 50  
  -> 10.0.0.139:http              Route   3      0          0           
  -> 10.0.0.137:http              Route   3      0          0

\[root@LVS-MASTER keepalived\]\#

查看日志/var/log/messages

\[root@LVS-MASTER keepalived\]\# tail -n 30/var/log/messages  
Apr 19 03:59:58 LVS-MASTER avahi-daemon\[2845\]: Withdrawing address record for10.0.0.148 on eth0.  
Apr 19 04:00:19 LVS-MASTER Keepalived: Starting Keepalived v1.2.1 (04/17,2012)  
Apr 19 04:00:19 LVS-MASTER Keepalived: Starting Healthcheck child process,pid=5960  
Apr 19 04:00:19 LVS-MASTER Keepalived\_healthcheckers: Netlink reflector reportsIP 10.0.0.136 added  
Apr 19 04:00:19 LVS-MASTER Keepalived\_healthcheckers: Netlink reflector reportsIP 10.0.0.159 added  
Apr 19 04:00:19 LVS-MASTER Keepalived\_healthcheckers: Registering Kernelnetlink reflector  
Apr 19 04:00:19 LVS-MASTER Keepalived\_healthcheckers: Registering Kernelnetlink command channel  
Apr 19 04:00:19 LVS-MASTER Keepalived\_healthcheckers: Opening file '/etc/keepalived/keepalived.conf'.  
Apr 19 04:00:19 LVS-MASTER Keepalived\_healthcheckers: Configuration is using :12257 Bytes  
Apr 19 04:00:19 LVS-MASTER Keepalived\_healthcheckers: Using LinkWatch kernelnetlink reflector...  
Apr 19 04:00:19 LVS-MASTER Keepalived\_healthcheckers: Activating healtcheckerfor service \[10.0.0.137:80\]  
Apr 19 04:00:19 LVS-MASTER Keepalived\_healthcheckers: Activating healtcheckerfor service \[10.0.0.139:80\]  
Apr 19 04:00:19 LVS-MASTER Keepalived\_vrrp: Netlink reflector reports IP10.0.0.136 added  
Apr 19 04:00:19 LVS-MASTER Keepalived\_vrrp: Netlink reflector reports IP10.0.0.159 added  
Apr 19 04:00:19 LVS-MASTER Keepalived\_vrrp: Registering Kernel netlinkreflector  
Apr 19 04:00:19 LVS-MASTER Keepalived\_vrrp: Registering Kernel netlink commandchannel  
Apr 19 04:00:19 LVS-MASTER Keepalived\_vrrp: Registering gratutious ARP sharedchannel  
Apr 19 04:00:19 LVS-MASTER Keepalived\_vrrp: Opening file'/etc/keepalived/keepalived.conf'.  
Apr 19 04:00:19 LVS-MASTER Keepalived\_vrrp: Configuration is using : 36698Bytes  
Apr 19 04:00:19 LVS-MASTER Keepalived\_vrrp: Using LinkWatch kernel netlinkreflector...  
Apr 19 04:00:19 LVS-MASTER Keepalived\_vrrp: VRRP sockpool: \[ifindex(2),proto(112), fd(11,12)\]  
Apr 19 04:00:19 LVS-MASTER Keepalived: Starting VRRP child process, pid=5961  
Apr 19 04:00:20 LVS-MASTER Keepalived\_vrrp: VRRP\_Instance(VI\_1) Transition toMASTER STATE  
Apr 19 04:00:21 LVS-MASTER Keepalived\_vrrp: VRRP\_Instance(VI\_1) Entering MASTERSTATE  
Apr 19 04:00:21 LVS-MASTER Keepalived\_vrrp: VRRP\_Instance(VI\_1) settingprotocol VIPs.  
Apr 19 04:00:21 LVS-MASTER Keepalived\_vrrp: VRRP\_Instance(VI\_1) Sendinggratuitous ARPs on eth0 for 10.0.0.148  
Apr 19 04:00:21 LVS-MASTER Keepalived\_healthcheckers: Netlink reflector reportsIP 10.0.0.136 added  
Apr 19 04:00:21 LVS-MASTER avahi-daemon\[2845\]: Registering new address recordfor 10.0.0.148 on eth0.  
Apr 19 04:00:21 LVS-MASTER Keepalived\_vrrp: Netlink reflector reports IP10.0.0.136 added  
Apr 19 04:00:26 LVS-MASTER Keepalived\_vrrp: VRRP\_Instance(VI\_1) Sendinggratuitous ARPs on eth0 for 10.0.0.148  
\[root@LVS-MASTER keepalived\]\#

**四、测试**

接下来做高可用性测试&故障切换测试......

**\#\#\#\#高可用性测试\#\#\#\#**

模拟故障，将LVS-MASTER上的keepalived服务停掉，然后观察LVS-BACKUP上的日志，信息如下

\[root@LVS-BACKUP keepalived\]\# tail -f /var/log/messages  
Apr 19 03:33:04 LVS-BACKUP Keepalived\_vrrp: VRRP\_Instance(VI\_1)Transition to MASTER STATE  
Apr 19 03:33:05 LVS-BACKUP Keepalived\_vrrp: VRRP\_Instance(VI\_1) Entering MASTERSTATE  
Apr 19 03:33:05 LVS-BACKUP Keepalived\_vrrp: VRRP\_Instance(VI\_1) settingprotocol VIPs.  
Apr 19 03:33:05 LVS-BACKUP Keepalived\_vrrp: VRRP\_Instance(VI\_1) Sendinggratuitous ARPs on eth0 for 10.0.0.148  
Apr 19 03:33:05 LVS-BACKUP Keepalived\_vrrp: Netlink reflector reports IP10.0.0.157 added  
Apr 19 03:33:05 LVS-BACKUP Keepalived\_healthcheckers: Netlink reflector reportsIP 10.0.0.157 added  
Apr 19 03:33:05 LVS-BACKUP avahi-daemon\[2825\]: Registering new address recordfor 10.0.0.148 on eth0.  
Apr 19 03:33:10 LVS-BACKUP Keepalived\_vrrp: VRRP\_Instance(VI\_1) Sendinggratuitous ARPs on eth0 for 10.0.0.148

从日志中可知，主机出现故障后，备机立刻检测到，此时备机变为MASTER角色，并且接管了主机的虚拟IP资源，最后将虚拟IP绑定在etho设备上。

将LVS-MASTER 上的keepalived服务开启后，LVS-BACKUP的日志状态。

Apr 19 03:34:02 LVS-BACKUP Keepalived\_vrrp: VRRP\_Instance(VI\_1) Received higher prio advert  
Apr 19 03:34:02 LVS-BACKUP Keepalived\_vrrp: VRRP\_Instance(VI\_1)Entering BACKUP STATE  
Apr 19 03:34:02 LVS-BACKUP Keepalived\_vrrp: VRRP\_Instance(VI\_1) removing protocol VIPs.  
Apr 19 03:34:02 LVS-BACKUP Keepalived\_vrrp: Netlink reflector reports IP 10.0.0.157 removed  
Apr 19 03:34:02 LVS-BACKUP Keepalived\_healthcheckers: Netlink reflector reports IP 10.0.0.157 removed  
Apr 19 03:34:02 LVS-BACKUP avahi-daemon\[2825\]: Withdrawing address record for 10.0.0.148 on eth0.

从日志可知，备机在检测到主机重新恢复正常后，释放了虚拟IP资源重新成为BACKUP角色

**\#\#\#\#故障切换测试\#\#\#\#**

故障切换是测试当某个节点出现故障后，Keepalived监制模块是否能及时发现然后屏蔽故障节点，同时将服务器转移到正常节点来执行。

将web2节点服务停掉，假设这个节点出现故障，然后主、备机日志信息如下

Apr 19 03:35:04 LVS-MASTER Keepalived\_healthcheckers:TCP connection to \[10.0.0.139:80\] failed!!!  
Apr 19 03:35:04 LVS-MASTER Keepalived\_healthcheckers:Removing service \[10.0.0.139:80\] from VS \[10.0.0.148:80\]  
Apr 19 03:35:04 LVS-MASTER Keepalived\_healthcheckers: Remote SMTP server \[127.0.0.1:25\] connected.

\[root@LVS-MASTER keepalived\]\# ipvsadm -L  
IP Virtual Server version 1.2.1 (size=4096)  
Prot LocalAddress:Port Scheduler Flags  
  -> RemoteAddress:Port           Forward Weight ActiveConn InActConn  
TCP  10.0.0.148:http rr persistent 50  
  -> 10.0.0.137:http              Route   3      0          0           
\[root@LVS-MASTER keepalived\]\#

从以上可以看出，Keepalived监控模块检测到10.0.0.139这台主机出现故障后，将些web2从集群系统中剔除掉了。 此时访问http://10.0.0.148只能看到web1了)

![keepalived][]

重新启动web2节点的服务，日志信息如下：

Apr 19 03:38:22 LVS-MASTER Keepalived\_healthcheckers:TCP connection to \[10.0.0.139:80\] success.  
Apr 19 03:38:22 LVS-MASTER Keepalived\_healthcheckers:Adding service \[10.0.0.139:80\] to VS \[10.0.0.148:80\]  
Apr 19 03:38:22 LVS-MASTER Keepalived\_healthcheckers: Remote SMTP server \[127.0.0.1:25\] connected.

\[root@LVS-MASTERkeepalived\]\# ipvsadm -L  
IP Virtual Server version 1.2.1 (size=4096)  
Prot LocalAddress:Port Scheduler Flags  
  -> RemoteAddress:Port           Forward Weight ActiveConn InActConn  
TCP  10.0.0.148:http rr persistent 50  
  -> 10.0.0.139:http              Route   3      0          0           
  -> 10.0.0.137:http              Route   3      0          0           
\[root@LVS-MASTER keepalived\]\#

Keepalived监控模块检测到10.0.0.139这台主机恢复正常后，又将此节点加入集群系统中，再次访问就可以访问到web2页面了）

![lvs][]

[2012081715214381.jpg]: /images/20220325/e5ce4506204e4b8798a94bf753139dac.png
[keepalived]: /images/20220325/a151d20c07964245b0773b5ac37eb033.png
[lvs]: /images/20220325/a2aabb0046ec408ea9dfc43bb1f62097.png