Red Hat Bugzilla – Bug 432783
Feature: Protect running update on shutdown
Last modified: 2008-02-14 12:51:40 EST
Description of proposed feature: Imagine a machine that is turned on after a few days off. Anacron will start pending cron.daily cron jobs. yum-cron is run and starts upgrading the system. Now the user turns off the machine, possibly in the middle of a running update. yum-cron should check for a running yum and if one is running block the stop action until yum is finished. The easiest solution for this would be to write the yum-cron daily script PID in a file and check for this file and PID in the yum-cron init stop action. If the file exists and the PID is the yum-cron daily cron script then it will wait and recheck every few seconds. An informative note should be printed to the shutdown screen and additionally there should be a trap that allows cancelling the stop (if it was run on the console).
Would be easy enough to code, but here are some big problems: 1) yum has a pid lock even during its (large) random wait before doing the actual work. The random wait is so that every machine around the world running yum-cron around the world doesn't assault the mirrors simultaneously, so is an important feature we wouldn't want to disable, but waiting hours for a shutdown is Bad. One could override it on console, but remotely one could get really trapped (shutdown also disables logins). 2) Messing with the shutdown scripts is outside the scope of this package. That's a core Fedora package, and changes there would have to be made by that package's owners. And very carefully thought about to deal with unintended consequences. But perhaps there is already a list of Things to Not Shut Down During that could be looked at? The upside would be a way to eliminate instances of rebooting with partial upgrades in progress, lots of loose files around, perhaps a corrupted rpm database. But, in practice I've not seen such problems in many years (and have clobbered machines in the midst of updates). I suspect that yum and rpm are now doing some cleanup when given a SIGTERM by the shutdown script, so that they're not left in an un-recoverable state. Since I can't make such a change as part of this package, I'll mark this bug as CANTFIX. There are two places it might be addressed, though. The "sysvinit" package owns the shutdown scripts. And some combination of yum and rpm could address how they handle being sent a SIGTERM by the shutdown scripts.