yum-cron Configuration in SL7

Un-modified yum-cron ALWAYS sends emails upon completion. This is an overwhelming flood given the number of systems we have. We therefore limit those that send emails to somewhat typical subsets, and further divide those out. The subsets are defined in cfengine3 classes.

• WNAllRepos[UM|MSU], combined into WNAllRepos, 10 total machines
• WNNotApplyYumUpdates, a subset of WNAllRepos, where all repos are enabled, but yum updates are not actually applied, 4 total machines
• yum_cron_email_emitters, machines that always email what they did, consisting of \x93msufs02|umfs06|WNAllRepos\x94. No other machine will send emails from yum-cron
• WNExtraEmailEmitters, 4 additional WN that also email when all repos get enabled

There are then 5 steps taken on the WN that are relevant

• At 9AM daily, a cron task runs on all WN except for the WNAllRepos class that sets the enabled repo set to only a few consisting mostly of just repos, sl-extras, and sl-security (considering adding sl-fastbugs)
• Any time prior to 6pm, a cluster_control command (no 11) can tell some set of SL7 WN to enable all of their repos instead. Typically this means all SL7 WN via some appropriate text file.
• Around 5am, yum-cron runs (staggered over about 2hrs or so) and does its thing. yum_cron_email_emitters machines will immediately send any relevant Emails
• At 7:30am, +5-0 minutes, the output file saved from the yum-cron run will be parsed, and Emails will be sent for relevant, interesting messages that are encountered, on the machine sets defined above that did not already send out Emails.

Then the cycle repeats.

yum-cron has a set of excluded rpms, including kernel* and openafs* (see /etc/yum/yum-cron.conf)

-- BobBall - 04 Oct 2018