Install Mongodb
From mongodb.org
From if-not-true-then-false.com
From php.net
To install mongodb, add the appropriate repo information below for your distribution version (x86_64 or i686) to /etc/yum.repos.d/10gen.repo:
vim /etc/yum.repos.d/10gen.repo
add
[10gen]
name=10gen Repository
baseurl=http://downloads-distro.mongodb.org/repo/redhat/os/x86_64
gpgcheck=0
or
[10gen]
name=10gen Repository
baseurl=http://downloads-distro.mongodb.org/repo/redhat/os/i686
gpgcheck=0
then run
yum update && yum install mongo-10gen mongo-10gen-server
Check the basic mongodb configuration settings before starting MongoDB (default settings are usually good)
vim /etc/mongod.conf
logpath=/var/log/mongo/mongod.log
port=27017
dbpath=/var/lib/mongo