Memcached部署(上)

memcached

Memcached多用于作为数据库的前端cache使用,从而减少数据库的负载。Memcached是一种内存缓存,用于存储键值对。
工作流程:

(1) 检查客户端请求的数据是否在Memcached中,如果在,把请求的数据返回给客户端。

(2) 客户端请求的数据不在Memcached中,就去查询后端数据库,把从后端数据库取得的数据返回给客户端,同时在 Memcached中备份一份。

(3) Memcached中的数据要和后端数据库中的数据保持一致。

(4) Memcached根据过期策略和LRU策略来清理内存空间。

1. memcached安装

  • 安装libevent

[root@chunlin Memcached]# tar -zxf libevent-2.1.8-stable.tar.gz
[root@chunlin Memcached]# cd libevent-2.1.8-stable
[root@chunlin libevent-2.1.8-stable]# mkdir /usr/local/libevent
[root@chunlin libevent-2.1.8-stable]# ./configure --prefix=/usr/local/libevent
[root@chunlin libevent-2.1.8-stable]# make
[root@chunlin libevent-2.1.8-stable]# make install

  • 安装memcached

[root@chunlin Memcached]# tar -zxf memcached-1.4.36.tar.gz
[root@chunlin Memcached]# cd memcached-1.4.36
[root@chunlin memcached-1.4.36]# mkdir /usr/local/memcached
[root@chunlin memcached-1.4.36]# ./configure --prefix=/usr/local/memcached
--with-libevent=/usr/local/libevent
[root@chunlin memcached-1.4.36]# make
[root@chunlin memcached-1.4.36]# make install

2. Mmecached的PHP 扩展

  • php的json扩展

php7中json的扩展包为jsond
[root@chunlin Memcached]# tar -zxf jsond-1.4.0.tgz
[root@chunlin Memcached]# cd jsond-1.4.0
[root@chunlin jsond-1.4.0]# /usr/local/php/bin/phpize --with-php-config=/usr/local/php/bin/php-config
#phpize命令用来生成configure脚本文件,这个命令一般在php安装目录的bin目录下
[root@chunlin jsond-1.4.0]# ./configure --with-php-config=/usr/local/php/bin/php-config
[root@chunlin jsond-1.4.0]# make
[root@chunlin jsond-1.4.0]# make test
[root@chunlin jsond-1.4.0]# make install

遇到的问题:
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解决:
[root@chunlin jsond-1.4.0]# yum install -y autoconf.noarch

  • php支持igbinary

下载igbinary
[root@chunlin Memcached]# tar -zxf igbinary-2.0.1.tgz
[root@chunlin Memcached]# cd igbinary-2.0.1
[root@chunlin igbinary-2.0.1]# /usr/local/php/bin/phpize --with-php-config=/usr/local/php/bin/php-config
[root@chunlin igbinary-2.0.1]# ./configure --with-php-config=/usr/local/php/bin/php-config --enable-igbinary
[root@chunlin igbinary-2.0.1]# make
[root@chunlin igbinary-2.0.1]# make test
[root@chunlin igbinary-2.0.1]# make install

  • php支持msgpack

下载msgpack
[root@chunlin Memcached]# tar -zxf msgpack-2.0.2.tgz
[root@chunlin Memcached]# cd msgpack-2.0.2
[root@chunlin msgpack-2.0.2]# /usr/local/php/bin/phpize
[root@chunlin msgpack-2.0.2]# ./configure --with-php-config=/usr/local/php/bin/php-config
[root@chunlin msgpack-2.0.2]# make
[root@chunlin msgpack-2.0.2]# make test
[root@chunlin msgpack-2.0.2]# make install

  • memcached的php扩展

下载memcached的php扩展包memcached
[root@chunlin Memcached]# tar -zxf memcached-3.0.2.tgz
[root@chunlin Memcached]# cd memcached-3.0.2
[root@chunlin memcached-3.0.2]# /usr/local/php/bin/phpize --with-php-config=/usr/local/php/bin/php-config
[root@chunlin memcached-3.0.2]# ./configure --with-php-config=/usr/local/php/bin/php-config --enable-memcached --with-libmemcached-dir=/usr/local/libmemcached --enable-memcached-igbinary --enable-memcached-json --enable-memcached-msgpack  
--disable-memcached-sasl
[root@chunlin memcached-3.0.2]# make
[root@chunlin memcached-3.0.2]# make test
[root@chunlin memcached-3.0.2]# make install
安装完每个PHP拓展包,都会在类似/usr/local/php/lib/php/extensions/no-debug-non-zts-20160303这样的目录下生成.so后缀的文件

  • 测试
    Memcahced的测试需要用到nginx和php,nginx和php的安装和配置详见http://www.cnblogs.com/NewStudy/p/7271539.html

    [root@chunlin ~]# vim /etc/php.ini
    #在文件最后添加对模块的扩展
    extension=igbinary.so
    extension=msgpack.so
    extension=jsond.so
    extension=memcached.so
    [root@chunlin ~]# /etc/init.d/php-fpm restart
    #重启FastCGI进程管理器
    #然后重启web服务器
    #浏览器中输入http://IP/index.php
    #index.php中的内容如下:

    <?php
    phpinfo();
    ?>;

浏览器显示结果如下所示:
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php页面中使用memcached
[root@chunlin html]# vim memcached.php

<?php
$mem = new Memcached();
$mem-> addServer("127.0.0.1",11211);
$mem-> set("test","Memcached test");
echo $mem-> get('test');
?>

#浏览器中输入http://IP/memcached.php出现Memcached test字样表示PHP与memcached之间的接口能正常工作了

3. Nagios监控Memcached

1) 安装check_memcached

软件:perl-Config-TinyNagios-Plugins-Memcached、epel源
环境:能执行perl程序的环境

[guest@host nagios]$ yum install -y perl-CPAN.noarch

[guest@host nagios]$ tar -zxf Nagios-Plugins-Memcached-0.02.tar.gz

[guest@host nagios]$ cd Nagios-Plugins-Memcached-0.02/

[guest@host Nagios-Plugins-Memcached-0.02]$ perl Makefile.PL

[guest@host Nagios-Plugins-Memcached-0.02]$ make

[guest@host Nagios-Plugins-Memcached-0.02]$ make install

安装完之后,我在我的/usr/local/bin目录下发现了check_memcached脚本,以为这样安装就算大功告成了,然而结果并不是这样,执行脚本时报错了

[root@host bin]# ./check_金沙官网线上,memcached --help
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解决办法:

[root@host perl]# rpm -ivh perl-Config-Tiny-2.14-7.el7.noarch.rpm
[guest@host bin]$ yum install -y perl-Nagios-Plugin.noarch

2) 配置memcached监控

[guest@host bin]$ cp check_memcached /usr/local/nagios/libexec/

[guest@host libexec]$ chmod 755 check_memcached

[guest@host libexec]$ cd /usr/local/nagios/etc/objects/

[guest@host objects]$ vim commands.cfg

define command{
    command_name    check_memcached_time
    command_line    $USER1$/check_memcached -H $HOSTADDRESS$ -w $ARG1$ -c $ARG2$
    }

define command{
    command_name    check_memcached_size
    command_line    $USER1$/check_memcached -H $HOSTADDRESS$ --size-warning $ARG1$ --size-critical $ARG2$
    }

define command{
    command_name    check_memcached_hit
    command_line    $USER1$/check_memcached -H $HOSTADDRESS$ --hit-warning $ARG1$ --hit-critical $ARG2$
    }

以上三个命令的定义依次为:
check_memcached_time:对时间的定义,单位为毫秒
check_memcached_size:对内存使用情况的定义,以百分比为单位
check_memcached_hit:对hit值的定义,以百分比为单位

[root@host objects]# vim services.cfg

define service{
    use                             local-service,services-pnp         ; Name of service template to use
    host_name                       chunlin
    service_description             Memcached_time
    check_command                   check_memcached_time!200!500
    notifications_enabled           0
    }

define service{
    use                             local-service,services-pnp         ; Name of service template to use
    host_name                       chunlin
    service_description             Memcached_size
    check_command                   check_memcached_size!80!90
    notifications_enabled           0
    }

define service{
    use                             local-service,services-pnp         ; Name of service template to use                           
    host_name                       chunlin
    service_description             Memcached_hit
    check_command                   check_memcached_hit!90!80
    notifications_enabled           0
    }

[root@host objects]# nagios -v /usr/local/nagios/etc/nagios.cfg
[root@host objects]# systemctl restart nagios.service

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