Memcached+magent Implementing Master-Slave synchronization +keepalived high-availability clusters

Memcached+magent implementation of Master-slave synchronization +keepalived High Availability cluster Introduction

Memcached is a high-performance distributed memory object caching system for dynamic Web applications to mitigate database load. It improves the speed of dynamic, database-driven Web sites by caching data and objects in memory to reduce the number of times a database is read. Memcached is based on a hashmap that stores key/value pairs. Its daemon (daemon) is written in C, but the client can write in any language and communicate with the daemon through the memcached protocol.

Experimental deployment

Host name	IP Address	main Service Software
Memcached Primary Server	172.16.10.138	Memcached,libevent,magent,keepalived
Memcached from the server	172.16.10.137	Memcached,libevent,keepalived
Client	172.16.10.134	Telnet test

• Configuring the Memcached Primary Cache node Server

tar xf libevent-2.1.8-stable.tar.gz -C /opttar xf memcached-1.5.6.tar.gz -C /opttar xf magent-0.5.tar.gz -C /optcd /opt/libevent-2.1.8./configure --prefix=/usr   #指定安装路径make && make install    #编译安装cd /opt/memcached-1.5.6./configure --with-libevent=/usr      #指定安装路径make && make install               #编译安装ln -s /usr/lib/libevent-2.1.so.6 /usr/lib64/libevent-2.1.so.6     #主服务器上magent服务需要这个模块

Cd/opt/magent

vim ketama.h #ifndef SSIZE_MAX                        #修改#define SSIZE_MAX 32767             #修改   #endifvim MakefileLIBS = -levent -lm                      

CP Mgent/usr/bin #把生成的mgent程序让系统识别

• Configuring memcached from a cache node server

tar xzvf memcached-1.5.6.tar.gz -C /opttar xzvf libevent-2.1.8-stable.tar.gz -C /optcd /opt/libevent-2.1.8./configure --prefix=/usrmake && make installcd /opt/memcached-1.5.6./configure --with-libevent=/usrmake && make i nstallln -s /usr/lib/libevent-2.1.so.6 /usr/lib64/libevent-2.1.so.6    #主服务器上magent服务需要这个模块

• The master server copies the magent files to the slave server

Yum Install openssh-clients

SCP magent [Email protected]:/usr/bin///Copy the resulting magent file directly to the slave server.

• Master server Install keepalived service, modify configuration file

Yum-y Install keepalived

Vim/etc/keepalived/keepalived.conf

router_id MAGENT_HA                                #router_id主从不能相同，要修改vrrp_script magent {    script "/opt/shell/magent.sh"    interval 2          }        #定义一个新函数，每2s自动执行这个脚本                        vrrp_instance VI_1 {state MASTER  #这边是主服务器，从服务器是BACKUP      interface ens33   #网卡接口是ens33                          virtual_router_id 51                              priority 100    #优先级，从服务器小于主服务器         advert_int 1authentication {         auth_type PASS         auth_pass 1111      }track_script {        magent      #触发执行magent脚本                 }virtual_ipaddress {        172.16.10.200    #虚拟IP（vip）       }      }将下面多余的配置全部删除

• Master server Install keepalived service, modify configuration file

Yum-y Install keepalived

Vim/etc/keepalived/keepalived.conf

router_id MAGENT_HB    #router_id主从不相同                vrrp_script magent {        script "/opt/shell/magent.sh"        interval 2          }    #定义一个新函数，每2s自动执行这个脚本  vrrp_instance VI_1 {state MASTER   #这边是从服务器，是BACKUP  interface ens33    #网卡接口是ens33virtual_router_id 51                       priority 90   #优先级，从服务器小于主服务器   advert_int 1authentication {auth_type PASSauth_pass 1111      }track_script {    magent     #触发执行magent脚本      }virtual_ipaddress {        172.16.10.200                                               #虚拟IP（vip）       }      }            将下面多余的配置全部删除

• master server Writing Magnet script

Mkdir/opt/shell

vim /opt/shell/magent.sh            #!/bin/bash      K=`ps -ef | grep keepalived | grep -v grep | wc -l`      if [ $K -gt 0 ]; then        magent -u root -n 51200 -l 192.168.58.100 -p 12000 -s 192.168.58.135:11211 -b 192.168.58.132:11211      else      pkill -9 magent      fi      -n 51200 #定义用户最大连接数      -l 192.168.58.100 #指定虚拟IP      -p 12000  #指定端口号      -s #指定主缓存服务器      -b #指定从缓存服务器       #这个脚本意思就是一旦检测到系统进程中有keepalived进程，就执行magent这条命令，如果没有，则将magent进程杀死。总得来说就是，主服务器上没有keepslived进程，magent就会和从服务器连接。            chmod +x /opt/shell/magent.sh        #给脚本添加执行权限

• Writing magent scripts from the server

Mkdir-p/opt/shell

vim /opt/shell/magent.sh#!/bin/bashK=`ip addr | grep 192.168.58.100 | grep -v grep | wc -l`if [ $K -gt 0 ]; thenmagent -u root -n 51200 -l 192.168.58.100 -p 12000 -s 192.168.58.135:11211 -b 192.168.58.132:11211elsepkill -9 magentfi  #从服务器的脚本意思就是检测到虚拟ip漂移是否到自己身上，如果VIP进行漂移到从服务器之后，就会执行magent这条命令，目的就是在主服务器宕掉的时候，从服务器能够正常启动。

• Experimental validation

First use the client to install Telnet, remote connection VIP node, after writing to the user, the master-slave cache server will automatically obtain the download of the user.

Memcached+magent Implementing Master-Slave synchronization +keepalived high-availability clusters