Something I do see commonly is that administrators who create Oracle Linux templates do disable a lot of the YUM channels. If you receive a template based installation in a private cloud setup it is good practice to first check which channels are activated and which have been disabled. If some of the channels, for example the addons channel, are disabled you might be missing out on a lot of things and find yourself in a “dependency hell”
Rather than trying to resolve this manually it is good to check the channel settings in /etc/yum/repos.d/* normally this will be /etc/yum.repos.d/public-yum-ol6.repo for OL6 machines.
A default installation will state enabled=0 for the public_ol6_adddons channel. To enable this you will have to state enabled=1
Even though it might sounds like a minor change, it is commonly overlooked in first instance. Additional channels are available for Oracle Linux from the public Oracle YUM server which might be of interest to administrators to enable.