Memcached server side

This server has private @IP : 192.168.33.14

Install memcached:

sudo apt-get install memcached

In /etc/memcached.conf, set up memory to 256 Mo:

-m 256

In /etc/memcached.conf, set up listening private @IP of the server:

# Specify which IP address to listen on. The default is to listen on all IP addresses
# This parameter is one of the only security measures that memcached has, so make sure
# it's listening on a firewalled interface.
#-l 127.0.0.2
-l 192.168.33.14

Web server side

This server has private @IP : 192.168.33.11

Install PHP extension

On the server that hosts nginx + php7.0:

sudo apt-get install -y php-memcached

Configure PHP

In /etc/php/7.0/fpm/php.ini:

[Session]
; Handler used to store/retrieve data.
; http://php.net/session.save-handler
#session.save_handler = files
session.save_handler = memcached
session.save_path = 'tcp://192.162.33.14:11211'

Restart services

sudo service php7.0-fpm restart && sudo service nginx restart

Check config

Create a phpinfo.php that calls phpinfo() and check memcached configuration.

Checking

Checking sessions are well handled by memcached

Let's write a simple script to check sessions:

session_start();
if(!isset($_SESSION['visit']))
{   
    echo "This is the first time you're visiting this server\n";
    $_SESSION['visit'] = 0;
}   
else
        echo "Your number of visits: ".$_SESSION['visit'] . "\n";

$_SESSION['visit']++;

echo "Server IP: ".$_SERVER['SERVER_ADDR'] . "\n";
echo "Client IP: ".$_SERVER['REMOTE_ADDR'] . "\n";
print_r($_COOKIE);

Checking memcached key/value server

Let's write a simple script to key/value access:

$mem = new Memcached();
$mem->addServer("192.168.33.14", 11211);
$result = $mem->get("blah");
if ($result) {
    echo $result;
} else {
    echo "No matching key found yet. Let's start adding that now!";
    $mem->set("blah", "I am data!  I am held in memcached!") or die("Couldn't save anything to memcached...");
}   

Dumping all key/value records

Sources

• https://www.digitalocean.com/community/tutorials/how-to-share-php-sessions-on-multiple-memcached-servers-on-ubuntu-14-04
• http://www.servermom.org/install-use-memcached-nginx-php-7-ubuntu-16-04/3670/