Magent搭建Memcached高可用群集

Magent缓存代理介绍

      因为Memcached服务器与服务器之间没有任何通讯，所以当任何服务器节点出现故障时，会出现单点故障。通过Magent缓存代理，防止单点现象。通过客户端连接到缓存代理服务器，缓存代理服务器可以连接多台Memcached机器并同时将每台Memcached机器进行数据同步。如果其中一台缓存服务器down机，系统依然可以继续工作，如果其中一台Memcached机器down掉，数据不会丢失并且可以保证数据的完整性。

原理演示图：

实验环境介绍：

三台服务器：

master/slave/client

实验步骤

在master和slave上同时安装libevent、memcached

master&&slave:

systemctl stop firewalld.service

setenforce 0

tar zxvf memcached-1.5.6.tar.gz -C /opt

tar zxvf libevent-2.1.8-stable.tar.gz -C /opt

yum install gcc gcc-c++ -y

cd /opt/libevent-2.1.8-stable/

./configure --prefix=/usr/local

make && make install

cp /usr/local/lib/libevent-2.1.so.6 /usr/lib64/

cd /opt/memcached-1.5.6/

./configure --with-libevent=/usr/local

make && make install

在master上安装配置magent

master:

mkdir /opt/magent

tar zxvf magent-0.5.tar.gz -C /opt

vim /opt/magent/ketama.h

     #ifndef SSIZE_MAX

     #define SSIZE_MAX 32767

     #endif

vim /opt/magent/Makefile

     LIBS = -levent -lm                 此处为英文单词‘l’,不是1

make

将magent命令复制到slave服务器上

注：标记地方为需要更改的位置

yum install openssl-clients -y

cp magent /usr/bin

scp magent [email protected]:/usr/bin

yum install keepalived -y

vim /etc/keepalived/keepalived.conf

       ! Configuration File for keepalived

        global_defs {

        notification_email {

        [email protected]

        [email protected]

        [email protected]

       }

        notification_email_from [email protected]

        smtp_server 192.168.200.1

        smtp_connect_timeout 30

        router_id MAGENT_HA

        }

       vrrp_script magent {

       script "/opt/shell/magent.sh"             脚本位置

       interval 2                                                  检测脚本为2秒

       }

       vrrp_instance VI_1 {

       state MASTER

       interface ens33

       virtual_router_id 51

       priority 100

      advert_int 1

      authentication {

      auth_type PASS

      auth_pass 1111

      }

      track_script {                   调用vrrp_script magent

           magent

     }

     virtual_ipaddress {

      192.168.218.16

      }

       }

从服务器上安装配置keepalived

slave:

yum install openssl-clients -y

yum install keepalived -y

cd /etc/keepalived/

mv keepalived.conf keepalived.conf.bk

master:

cd /etc/keepalived/

scp keepalived.conf [email protected]:/etc/keepalived/keepalived.conf

slave:

vim /etc/keepalived/keepalived.conf

            global_defs {

            router_id MAGENT_HB

           vrrp_instance VI_1 {

            state BACKUP

            virtual_router_id 52

             priority 90

master:

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 192.168.218.16 -p 12000 -s 192.168.218.130:11211 -b 192.168.218.157:11211
         else
            pkill -9 magent
       fi

chmod +x /opt/shell/magent.sh

systemctl start keepalived.servic

netstat -ntap | grep 12000                  #此时检查应有12000端口号

slave:

mkdir /opt/shell

vim /opt/shell/magent.sh

       #!/bin/bash
       K=`ip addr | grep 192.168.218.16 | grep -v grep | wc -l`
       if [ $K -gt 0 ];then
          magent -u root -n 51200 -l 192.168.218.16 -p 12000 -s 192.168.218.130:11211 -b 192.168.218.157:11211
       else
           pkill -9 magent
       fi

#magent -u指定用户、-n指定连接数量、-l指定漂移地址、-p指定端口、-s指定主服务器地址、-b指定从服务器地址

chmod +x /opt/shell/magent.sh

systemctl start keepalived.servic

netstat -ntap | grep 12000                   #此时检查应有12000端口号

master:

memcached -m 512k -u root -d -l 192.168.218.130 -p 11211

netstat -ntap | grep 11211

slave:

memcached -m 512k -u root -d -l 192.168.218.157 -p 11211

netstat -ntap | grep 11211

测试：

master:

yum install telnet -y

telnet 192.168.218.130 11211

slave:

yum install telnet -y

telnet 192.168.218.157 11211

client：

yum install telnet -y

telnet 192.168.218.16 12000

         Trying 192.168.218.16...

         Connected to 192.168.218.16.

         Escape character is '^]'.

         add username 0 0 7                #写入一段数据

         1231231

          STORED

slave:

telnet 192.168.218.157 11211

          Trying 192.168.218.157...

          Connected to 192.168.218.157.

         Escape character is '^]'.

         get username

         VALUE username 0 7

        1231231                                  #在主服务器和从服务器上可以看到同步过来的数据

        END