It is well documented in Apple Support articles, the OS X Support Essentials Book, and on other sites about using the createinstallmedia command to make a full OS X Install disk. However, with Yosemite, while the command still exists and using the disk you created for an install works the first time, an issue seems to occur on older Macs (non-retina, circa 2012 and older) on subsequent installs.
The OS X Installer's standard operating procedure is to create/update the recovery partition and then restart into the recovery partition. However, on subsequent installs with a Yosemite-created full OS X Install disk, the recovery partition is not created or updated on older Macs. The installer also looks different, a customize button exists, and you able to turn off the installer components!