Magent搭建Memcached高可用群集

Magent緩存代理介紹

      因為Memcached服務器與服務器之間沒有任何通訊，所以當任何服務器節點出現故障時，會出現單點故障。通過Magent緩存代理，防止單點現象。通過客戶端連接到緩存代理服務器，緩存代理服務器可以連接多臺Memcached機器并同時將每臺Memcached機器進行數據同步。如果其中一臺緩存服務器down機，系統依然可以繼續工作，如果其中一臺Memcached機器down掉，數據不會丟失并且可以保證數據的完整性。

原理演示圖：

實驗環境介紹：

三臺服務器：

master/slave/client

實驗步驟

在master和slave上同時安裝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上安裝配置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                 此處為英文單詞‘l’,不是1

make

將magent命令復制到slave服務器上

注：標記地方為需要更改的位置

yum install openssl-clients -y

cp magent /usr/bin

scp magent root@192.168.218.157:/usr/bin

yum install keepalived -y

vim /etc/keepalived/keepalived.conf

       ! 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 192.168.200.1

        smtp_connect_timeout 30

        router_id MAGENT_HA

        }

       vrrp_script magent {

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

       interval 2                                                  檢測腳本為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 {                   調用vrrp_script magent

           magent

     }

     virtual_ipaddress {

      192.168.218.16

      }

       }

從服務器上安裝配置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 root@192.168.218.157:/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                  #此時檢查應有12000端口號

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指定用戶、-n指定連接數量、-l指定漂移地址、-p指定端口、-s指定主服務器地址、-b指定從服務器地址

chmod +x /opt/shell/magent.sh

systemctl start keepalived.servic

netstat -ntap | grep 12000                   #此時檢查應有12000端口號

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

測試：

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                #寫入一段數據

         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                                  #在主服務器和從服務器上可以看到同步過來的數據

        END