The yum update utility can be run by hand from the command line, called through one of the provided front-end tools,or configured to run automatically at specified intervals.
Manually Check for Package Updates
The following command prints a list of packages that need to be updated:
# yum check-update
To actually install these updates, run:
# yum update
Configure Automatic Update Retrieval and Installation with Cron
The yum-updatesd service is not mature enough for an enterprise environment, and the service may introduce unnecessary overhead. When possible, replace this service with a cron job that calls yum directly.
Disable the yum-updatesd service:
# chkconfig yum-updatesd off
Create the file yum.cron, make it executable, and place it in /etc/cron.daily:
/usr/bin/yum -R 120 -e 0 -d 0 -y update yum
/usr/bin/yum -R 10 -e 0 -d 0 -y update
This particular script instructs yum to update any packages it finds. Placing the script in /etc/cron.
daily ensures its daily execution. To only apply updates once a week, place the script in /etc/cron.weekly instead.