Bug 744335

Description of problem:
yum-cron has no documentation

Version-Release number of selected component (if applicable):
3.2.29-17.el6

How reproducible:
Always

Steps to Reproduce:
1. rpm -ql yum-cron
2. Look for something in /usr/share/doc
3. Look for a man page
  
Actual results:
Only a COPYING file in /usr/share/doc, no man-page at all.

Expected results:
Some kind of minimal documentation explaining what the configurables are and how to use them.

Additional info:
Documentation is especially important because the configuration used by yum-cron is obtuse, relying on rarely used patterns and poorly documented features in other packages.  Examples of this behavior include:

1) The use of an init.d script to pseudo-enable/disable a cron job.  This is an unusual design-pattern, I'm not aware of any other cron-scripts that are managed this way and a sysconfig option would be a much saner way to provide the feature.  If the pseudo-service model is going to be employed it should be documented thoroughly.

2) The yum-cron service defaults to off for all runlevels, so the package doesn't perform it's function unless you perform the undocumented step of enabling the pseudo-service (that as mentioned above isn't required for any other cron job).

3) The use of the yum shell feature.  Few admins are familiar with the yum-shell feature, and it's not documented all that well elsewhere.  For example, the "ts" command used in yum-cron's yum shell files isn't documented in either the yum manpage or in the yum-shell manpage.  You have to run "yum shell" and then type help from the shell itself to see any mention of the "ts" shorthand.

4) The /etc/sysconfig file is full of double-negatives like "CHECK_ONLY" and "DOWNLOAD_ONLY".  These kinds of poorly names variables need verbose explanations like "CHECK_ONLY=yes causes yum-cron to check for the availability of updates without downloading or installing them.  Defaults to no, meaning that updates will be downloaded and installed."  In many ways, it might be better just to fix the varnames to be CHECK_FIRST, CHECK, DOWNLOAD, and INSTALL, all of which default to yes in order to install updates.  If you only want to download, you turn off INSTALL.  If you only want to check, you turn off DOWNLOAD.  But barring sane varnames, the comments should be verbose and explicit about what "yes" means and what "no" means.

Many of these shortcomings were observed as early as 2005: http://forums.fedoraforum.org/archive/index.php/t-73354.html