php-pecl-memcache package is not included in the default CentOS repositories. It can be installed from the Remi repository.

In order to install php-pecl-memcache, you need to have root permission.

STEP 1. Enabling the Remi repository

sudo yum install epel-release yum-utils
sudo yum install
sudo yum-config-manager --enable remi

STEP 2. Install the mcrypt package by typing:

sudo yum -y install php-pecl-memcache