如何搭建memcache群集实现高可用？

1.1&＃xff1a;环境

• VMware软件
• 一台centos7虚拟机作为memcache主服务器&＃xff0c;IP地址&＃xff1a;192.168.79.133
• 一台centos7虚拟机作为memcache从服务器&＃xff0c;IP地址&＃xff1a;192.168.79.134
• 一台centos7虚拟机作为memcache客户端&＃xff0c;IP地址&＃xff1a;192.168.79.135
• 漂移IP地址&＃xff1a;192.168.79.100&＃xff0c;是客户端登陆的IP地址

1.2&＃xff1a;试验目的

• 通过搭建memcache高可用群集&＃xff0c;实现主从同步&＃xff0c;群集高可用功能

1.3&＃xff1a;magent概述

• Magent是一款开源的Memcached代理服务器软件&＃xff0c;采用的是:Consistent Hashing原理&＃xff0c;可以通过它来实现缓存数据的同步

• 主服务器需要安装&＃xff1a;memcached&＃xff0c;libevent&＃xff0c;keepalived&＃xff0c;magent
• 从服务器需要安装&＃xff1a;memcached&＃xff0c;libevent&＃xff0c;keepalived

2.1&＃xff1a;主从服务器搭建memcached

• 以下的步骤主从服务器都需要操作&＃xff0c;再次仅展示主服务器的操作

• &＃39;//解压源码包&＃39;
[root&＃64;master ~]# mount.cifs //192.168.23.1/ccc /mnt
Password for root&＃64;//192.168.23.1/ccc:
[root&＃64;master ~]# cd /mnt/memcache/
[root&＃64;master memcache]# tar zxvf libevent-2.1.8-stable.tar.gz -C /opt
[root&＃64;master memcache]# tar zxvf memcached-1.5.6.tar.gz -C /opt
[root&＃64;master memcache]# mkdir /opt/magent &＃39;//此步骤从服务器不需要操作&＃39;
[root&＃64;master memcache]# tar zxvf magent-0.5.tar.gz -C /opt/magent/ &＃39;//此步骤从服务器不需要操作&＃39;
&＃39;//编译安装libevent和memcached&＃39;
[root&＃64;master memcache]# yum install gcc gcc-c&＃43;&＃43; make -y
[root&＃64;master memcache]# cd /opt/libevent-2.1.8-stable/
[root&＃64;master libevent-2.1.8-stable]# ./configure --prefix&＃61;/usr &＃39;//路径不在/usr的话&＃xff0c;后面magent在make的时候会报错&＃xff1a;magent.c:64:19: 致命错误&＃xff1a;event.h&＃xff1a;没有那个文件或目录&＃39;
[root&＃64;master libevent-2.1.8-stable]# make && make install
[root&＃64;master libevent-2.1.8-stable]# cd /opt/memcached-1.5.6/
[root&＃64;master memcached-1.5.6]# ./configure \
> --prefix&＃61;/usr/local/memcached \
> --with-libevent&＃61;/usr/local/libevent
[root&＃64;master memcached-1.5.6]# make && make install
&＃39;//关闭防火墙&＃39;
[root&＃64;master memcached-1.5.6]# systemctl stop firewalld.service
[root&＃64;master memcached-1.5.6]# setenforce 0

2.2&＃xff1a;主服务器上安装magent代理

• 在主服务器上安装magent&＃xff0c;从服务器不需要安装

• [root&＃64;master memcached-1.5.6]# cd /opt/magent/
[root&＃64;master magent]# ls
ketama.c ketama.h magent.c Makefile
[root&＃64;master magent]# vim ketama.h &＃39;//修改magent配置文件&＃39;&＃39;//前两行修改如下&＃39;
#ifndef SSIZE_MAX
#define SSIZE_MAX 32767
...省略内容
[root&＃64;master magent]# vim Makefile &＃39;//修改Makefile配置文件&＃39;LIBS &＃61; -levent -lm &＃39;//首行后面添加-lm&＃39;
...省略内容
[root&＃64;master magent]# make &＃39;//编译后会产生一个magent可执行程序&＃39;
[root&＃64;master magent]# yum install openssh-clients -y
[root&＃64;master magent]# cp magent /usr/bin/ &＃39;//将magent可执行程序复制到/usr/bin中&＃39;
[root&＃64;master magent]# scp magent root&＃64;192.168.79.134:/usr/bin &＃39;//将magent可执行程序复制到从服务器的/usr/bin中&＃39;
&＃39;//此命令需要输入yes&＃xff0c;输入从服务器的密码才能将文件拷贝过去&＃xff0c;根据提示操作即可&＃39;


2.3&＃xff1a;主从服务器搭建keepalived

• [root&＃64;master ~]# yum install keepalived -y
&＃39;//主从服务器都要安装keepalived&＃39;


• 主服务器中keepalived.conf配置文件修改

  [root&＃64;master ~]# vim /etc/keepalived/keepalived.conf
! Configuration File for keepalived&＃39;//此段落为&＃xff1a;定义一个函数脚本&＃xff0c;稍后我们需要创建它&＃39;
vrrp_script magent { script "/opt/shell/magent.sh"interval 2}
&＃39;//全局配置&＃39;
global_defs {notification_email {acassen&＃64;firewall.locfailover&＃64;firewall.locsysadmin&＃64;firewall.loc}notification_email_from Alexandre.Cassen&＃64;firewall.locsmtp_server 192.168.200.1smtp_connect_timeout 30router_id MAGENT_HA &＃39;//router_id自定义&＃xff0c;不可与从服务器相同&＃39;
}
&＃39;//实例区域&＃39;
vrrp_instance VI_1 { state MASTER &＃39;//主服务器为MASTER&＃xff0c;从服务器要改为BACKUP&＃39;interface ens33 &＃39;//网卡改为本机网卡ens33&＃39;virtual_router_id 51 &＃39;//主不可相同&＃xff0c;从服务器需要修改&＃39;priority 100 &＃39;//优先级要高于从服务器&＃39;advert_int 1track_script { &＃39;//此三行为调用函数的段落&＃xff0c;配置文件开头已经添加了函数&＃xff0c;此处需要调用&＃39;magent}authentication {auth_type PASSauth_pass 1111}virtual_ipaddress {192.168.79.100 &＃39;//定义漂移地址&＃39;}
}

• 从服务器中keepalived.conf配置文件修改

  [root&＃64;slave ~]# cd /etc/keepalived/
[root&＃64;slave keepalived]# mv keepalived.conf keepalived.conf.bak &＃39;//备份配置文件&＃39;&＃39;//回到主服务器&＃xff0c;将配置文件复制到从服务器&＃39;
[root&＃64;master ~]# scp /etc/keepalived/keepalived.conf root&＃64;192.168.79.134:/etc/keepalived
[root&＃64;slave keepalived]# vim keepalived.conf&＃39;//其他配置都相同&＃xff0c;只需要修改如下几个配置&＃39;
router_id MAGENT_HB &＃39;//id名和第一台要不一样&＃xff0c;从服务器改为MAGENT_HB&＃39;
state BACKUP &＃39;//从服务器为BACKUP&＃39;
virtual_router_id 52 &＃39;//id号和第一台不一样即可&＃39;
priority 90 &＃39;//优先级低与主服务器 &＃39;

• 在主从服务器创建magent脚本

  &＃39;//主从服务器都要创建magent脚本&＃39;
[root&＃64;master ~]# mkdir /opt/shell
[root&＃64;master ~]# cd /opt/shell/
[root&＃64;master shell]# vim magent.sh
#!/bin/bash
K&＃61;&＃96;ps -ef | grep keepalived | grep -v grep | wc -l&＃96;
if [ $K -gt 0 ]; thenmagent -u root -n 51200 -l 192.168.79.100 -p 12000 -s 192.168.79.133:11211 -b 192.168.79.134:11211
else
pkill -9 magent
fi
&＃39;//如下解释&＃39;
-n 51200 &＃39;//定义用户最大连接数&＃39;
-l 192.168.79.100 &＃39;//指定虚拟IP&＃39;
-p 12000 &＃39;//指定端口号&＃39;
-s &＃39;//指定主缓存服务器192.168.79.133:11211&＃39;
-b &＃39;//指定从缓存服务器192.168.79.134:11211&＃39;
11211 &＃39;//端口号&＃39;


• 主从服务器启动服务

  &＃39;//主从服务器都要做&＃39;
[root&＃64;master shell]# chmod &＃43;x magent.sh &＃39;//增加magent脚本执行权限&＃39;
[root&＃64;master shell]# systemctl start keepalived.service &＃39;//开启keepalived服务&＃39;
[root&＃64;master shell]# netstat -ntap |grep 12000 &＃39;//keepalived启动会有点慢&＃xff0c;我们需要稍等一下&＃39;
tcp 0 0 192.168.79.100:12000 0.0.0.0:* LISTEN 67513/magent


• 验证主从

  [root&＃64;master shell]# vim /var/log/messages
搜索&＃39;//Transition to MASTER STATE&＃39;&＃xff0c;有即成功
[root&＃64;master shell]# ip addr &＃39;//查看漂移地址是否绑定成功&＃39;
...省略内容inet 192.168.79.100/32 scope global ens33 &＃39;//绑定成功 &＃39;
...省略内容
[root&＃64;slave keepalived]# vim /var/log/messages
搜索&＃39;//Entering BACKUP STATE&＃39;&＃xff0c;有即成功
[root&＃64;slave keepalived]# ip addr &＃39;//查看漂移地址是否绑定成功&＃39;
...省略内容inet 192.168.79.100/32 scope global ens33 &＃39;//绑定成功 &＃39;
...省略内容


2.4&＃xff1a;主从服务器开启memcache并测试本地连接

• 主从服务器开启memcache

• &＃39;//主服务器开启&＃39;
[root&＃64;master ~]# ln -s /usr/local/memcached/bin/* /usr/local/bin/
[root&＃64;master ~]# memcached -m 512k -u root -d -l 192.168.79.133 -p 11211
[root&＃64;master ~]# netstat -ntap |grep 11211
tcp 0 0 192.168.79.133:11211 0.0.0.0:* LISTEN 88178/memcached
[root&＃64;master ~]#
&＃39;//从服务器开启&＃39;
[root&＃64;slave keepalived]# ln -s /usr/local/memcached/bin/* /usr/local/bin/
[root&＃64;slave keepalived]# memcached -m 512k -u root -d -l 192.168.79.134 -p 11211
[root&＃64;slave keepalived]# netstat -ntap |grep 11211
tcp 0 0 192.168.79.134:11211 0.0.0.0:* LISTEN 124927/memcached


• 测试本地能否连接memcache

  &＃39;//主服务器测试&＃39;
[root&＃64;master ~]# yum install telnet -y &＃39;//安装Telnet远程登陆程序&＃39;
[root&＃64;master ~]# telnet 192.168.79.133 11211
Trying 192.168.79.133... &＃39;//连接成功&＃39;
Connected to 192.168.79.133.
Escape character is &＃39;^]&＃39;.
quit &＃39;//退出&＃39;
Connection closed by foreign host.
&＃39;//从服务器测试&＃39;
[root&＃64;slave keepalived]# yum install telnet -y
[root&＃64;slave keepalived]# telnet 192.168.79.134 11211
Trying 192.168.79.134... &＃39;//连接成功&＃39;
Connected to 192.168.79.134.
Escape character is &＃39;^]&＃39;.
quit &＃39;//退出&＃39;
Connection closed by foreign host.

• 客户端登陆memcache

  [root&＃64;client ~]# yum install telnet -y
[root&＃64;client ~]# telnet 192.168.79.100 12000 &＃39;//使用漂移地址登陆&＃39;
Trying 192.168.79.100...
Connected to 192.168.79.100.
Escape character is &＃39;^]&＃39;.

• 测试主从同步

  [root&＃64;client ~]# telnet 192.168.79.100 12000
Trying 192.168.79.100...
Connected to 192.168.79.100.
Escape character is &＃39;^]&＃39;.
add username 0 0 5 &＃39;//客户端连接并新建一个数据&＃39;
12345
STORED
&＃39;//返回主服务器查看是否同步生成数据&＃39;
[root&＃64;master ~]# telnet 192.168.79.133 11211
Trying 192.168.79.133...
Connected to 192.168.79.133.
Escape character is &＃39;^]&＃39;.
get username
VALUE username 0 5
12345 &＃39;//主服务器成功生成&＃39;
END
&＃39;//返回从服务器查看是否同步生成数据&＃39;
[root&＃64;slave keepalived]# telnet 192.168.79.134 11211
Trying 192.168.79.134...
Connected to 192.168.79.134.
Escape character is &＃39;^]&＃39;.
get username
VALUE username 0 5
12345 &＃39;//从服务器成功生成&＃39;
END
&＃39;//测试成功&＃xff0c;主从都成功生成数据&＃39;


• 测试高可用群集

  &＃39;//宕机主服务器&＃xff0c;看从服务器是否正常使用&＃39;
[root&＃64;master ~]# systemctl stop keepalived.service &＃39;//关闭主服务器keepalived服务&＃39;
[root&＃64;client ~]# telnet 192.168.79.100 12000 &＃39;//客户端登陆成功&＃39;
Trying 192.168.79.100...
Connected to 192.168.79.100.
Escape character is &＃39;^]&＃39;.
set username
UNSUPPORTED COMMAND
set username 0 0 4 &＃39;//修改一下数据&＃39;
1234
STORED
&＃39;//从服务器查看数据是否同步&＃39;
get username
VALUE username 0 4
1234 &＃39;//成功同步&＃39;
END

• 高可用群集搭建成功