Connecting to Memcached on the Libmemcached (PHP)

Prerequisites

• The DCS Memcached instance you want to access is in the Running state.
• Log in to the ECS. For details on how to create ECSs, see the Elastic Cloud Server User Guide.
  

  An ECS can communicate with a DCS instance that belongs to the same VPC and is configured with the same security group.

  • If the ECS and DCS instance are in different VPCs, establish a VPC peering connection to achieve network connectivity between the ECS and DCS instance. For details, see Does DCS Support Cross-VPC Access?
  • If different security groups have been configured for the ECS and DCS instance, set security group rules to achieve network connectivity between the ECS and DCS instance. For details, see How Do I Configure a Security Group?

OSs of Red Hat Series

The following uses CentOS 7.0 as an example to describe how to install a PHP client and use it to access a DCS Memcached instance. The procedure is also applicable to a PHP client running the Red Hat or Fedora OS.

1. Install GCC-C++ and Make compilation components.

   yum install gcc-c++ make

2. Install related SASL packages.

   yum install cyrus-sasl*

3. Install the libMemcached library.

   Installing the libMemcached library requires SASL authentication parameters. Therefore, you cannot install the library by running the yum command.

   wget https://launchpad.net/libmemcached/1.0/1.0.18/+download/libmemcached-1.0.18.tar.gz

   tar -xvf libmemcached-1.0.18.tar.gz

   cd libmemcached-1.0.18

   ./configure --prefix=/usr/local/libmemcached --enable-sasl

   make && make install

   

   Before installing the libMemcached library, install GCC-C++ and SASL components. Otherwise, an error will be reported during compilation. After you resolve the error, run the make clean command and then run the make command again.

4. Install the PHP environment.

   yum install php-devel php-common php-cli

   

   PHP 7.x does not support SASL authentication. Use PHP 5.6. If the yum php version is not 5.6, download one from the Internet.

5. Install the Memcached client.

   Note that you must add a parameter used to enable SASL when running the configure command.

   wget http://pecl.php.net/get/memcached-2.1.0.tgz

   tar zxvf memcached-2.1.0.tgz

   cd memcached-2.1.0

   phpize

   ./configure --with-libmemcached-dir=/usr/local/libmemcached --enable-memcached-sasl

   make && make install

6. Modify the php.ini file.

   Run the find or locate command to find the php.ini file.

   find / -name php.ini

   Add the following two lines to the php.ini file:

   extension=memcached.so
   memcached.use_sasl = 1

   Figure 1 Modifying the php.ini file
   

7. Access a DCS Memcached instance.

   Create a memcached.php file and add the following content to the file:

   <?php
       $connect = new Memcached; //Declares a Memcached connection.
       $connect->setOption(Memcached::OPT_COMPRESSION, false); //Disables compression.
       $connect->setOption(Memcached::OPT_BINARY_PROTOCOL, true); //Uses the binary protocol.
       $connect->setOption(Memcached::OPT_TCP_NODELAY, true); //Disables the TCP network delay policy.
       $connect->addServer('{memcached_instance_ip}', 11211); //Specifies the instance IP address and port number.
       $connect->setSaslAuthData('{username}', '{password}'); //If password-free access is enabled for the instance, delete or comment out this line.
       $connect->set("DCS", "Come on!");
       echo 'DCS: ',$connect->get("DCS");
       echo "\n";
       $connect->quit();
   ?>

   Save and run the memcached.php file. The following result is displayed.

   [root@testphpmemcached ~]# php memcached.php 
       DCS: Come on!
   [root@testphpmemcached ~]# 

OSs of Debian Series

The following uses the Ubuntu OS as an example to describe how to install a PHP client and use it to access a DCS Memcached instance.

1. Install GCC and Make compilation components.

   apt install gcc make

2. Install the PHP environment.

   PHP 5.x is recommended for better compatibility with SASL authentication.

   Run the following commands to add the image source of PHP of an earlier version, and then install the php.5.6 and php.5.6-dev packages:

   apt-get install -y language-pack-en-base;

   LC_ALL=en_US.UTF-8;

   add-apt-repository ppa:ondrej/php;

   apt-get update;

   apt-get install php5.6 php5.6-dev;

   After the installation is complete, run the php -version command to check the PHP version. If the following result is displayed, the PHP version is 5.6, indicating that PHP 5.6 is successfully installed.

   root@dcs-nodelete:/etc/apt# php -version
   PHP 5.6.36-1+ubuntu16.04.1+deb.sury.org+1 (cli) 
   Copyright (c) 1997-2016 The PHP Group

   

   To uninstall PHP, run the following commands:

   apt install aptitude -y

   aptitude purge `dpkg -l | grep php| awk '{print $2}' |tr "\n" " "`

3. Install the SASL component.

   apt install libsasl2-dev cloog.ppl

4. Install the libMemcached library.

   wget https://launchpad.net/libmemcached/1.0/1.0.18/+download/libmemcached-1.0.18.tar.gz

   tar -xvf libmemcached-1.0.18.tar.gz

   cd libmemcached-1.0.18

   ./configure --prefix=/usr/local/libmemcached

   make && make install

   

   Before installing the libMemcached library, install GCC-C++ and SASL components. Otherwise, an error will be reported during compilation. After you resolve the error, run the make clean command and then run the make command again.

5. Install the Memcached client.

   Install the zlib component.

   apt install zlib1g.dev

   Note that you must add a parameter used to enable SASL when running the configure command.

   wget http://pecl.php.net/get/memcached-2.2.0.tgz;

   tar zxvf memcached-2.2.0.tgz;

   cd memcached-2.2.0;

   phpize5.6;

   ./configure --with-libmemcached-dir=/usr/local/libmemcached --enable-memcached-sasl;

   make && make install;

6. Modify the pdo.ini file.

   Run the following command to find the pdo.ini file:

   find / -name pdo.ini

   By default, the pdo.ini file is stored in the /etc/php/5.6/mods-available directory. Add the following two lines to the php.ini file:

   extension=memcached.so
   memcached.use_sasl = 1

   Figure 2 Modifying the pdo.ini file
   

7. Access a DCS Memcached instance.

   Create a memcached.php file and add the following content to the file:

   <?php
       $connect = new Memcached; //Declares a Memcached connection.
       $connect->setOption(Memcached::OPT_COMPRESSION, false); //Disables compression.
       $connect->setOption(Memcached::OPT_BINARY_PROTOCOL, true); //Uses the binary protocol.
       $connect->setOption(Memcached::OPT_TCP_NODELAY, true); //Disables the TCP network delay policy.
       $connect->addServer('{memcached_instance_ip}', 11211); //Specifies the instance IP address and port number.
       $connect->setSaslAuthData('{username}', '{password}'); //If password-free access is enabled for the instance, delete or comment out this line.
       $connect->set("DCS", "Come on!");
       echo 'DCS: ',$connect->get("DCS");
       echo "\n";
       $connect->quit();
   ?>

   Save and run the memcached.php file. The following result is displayed.

   [root@dcs-nodelete ~]# php memcached.php 
       DCS: Come on!
   [root@dcs-nodelete ~]#