[CentOS] Understanding yum automatic upgrades

Tue Apr 5 18:38:30 UTC 2011
email builder <emailbuilder88 at yahoo.com>

Hello,

  Sorry if this is somewhat naive, but I'm a little confused as to what the 
criteria is for that which will get upgraded automatically by yum and what will 
not.

  I see in our logwatch messages from time to time that yum upgraded a bunch of 
stuff, but I also notice that yum will not upgrade other packages at all (easy 
example is clamav, but there are others).

  Can someone explain or point me to where I can read about the distinction 
between what is and is not subjected to automatic upgrade?

Thanks!