Install MongoDB in Ubuntu 12.04 with PHP driver

Install MongoDB:

sudo apt-key adv --keyserver hkp://keyserver.ubuntu.com:80 --recv 7F0CEB10
echo 'deb http://downloads-distro.mongodb.org/repo/ubuntu-upstart dist 10gen' | sudo tee /etc/apt/sources.list.d/mongodb.list
sudo apt-get update
sudo apt-get install mongodb-10gen

Install MongoDB PHP driver:

sudo apt-get install php-pear php5-dev
pecl search mongo
sudo pecl install mongo

Configure MongoDB PHP driver: Create a file called /etc/php5/mods-available/mongo.ini with this content:

extension=mongo.so

And create a symlink to it in /etc/php5/conf.d/:

cd /etc/php5/conf.d
sudo ln -s ../mods-available/mongo.ini 20-mongo.ini

Then restart Apache:

sudo service apache2 restart

Start, stop and restart MongoDB:

sudo service mongodb start
sudo service mongodb stop
sudo service mongodb restart

Configuration file:

/etc/mongodb.conf

Log file:

/var/log/mongodb/mongodb.log

Data files:

/var/lib/mongodb

Ref: http://docs.mongodb.org/manual/tutorial/install-mongodb-on-ubuntu/