Issue

You receive the following error when trying to run an application (such as rrdtool),

No fonts found; this probably means that the fontconfig
library is not correctly configured. You may need to
edit the fonts.conf configuration file. More information
about fontconfig can be found in ....

Solution

Run

yum install deja*

If you receive the following, 

--> Finished Dependency Resolution
Error: dejavu-fonts conflicts with fontconfig >= 2.3.0 

Then run

yum install dejavu-lgc-fonts.noarch