How do you know when a reboot is required after yum update?

[Roberto Ragusa]

Donald Russell wrote:
> Obviously a reboot is required when loading a new kernel....
> 
> But in general, does yum leave some breadcrumb clue that some other
> process can check? For example, maybe there's something in the package
> files that yum sees and creates a "/rebootRequired" file which is always
> deleted upon booting?
> 
> If not, I think that'd be a cool idea.. the file could be
> /rebootRequired.txt
> 
> and contain a plain text list of packages that caused the condition. :-)

It is quite apparent that you have a Windows like mindset. I say this
without any will to offend you; I just observe:
1) the reboot idea
2) the file name with lowercase and uppercase mixed
3) the file extension .txt

:-)

Now the serious answer.
The kernel case is obvious; installing a kernel is useless without a reboot.
But in other cases the new stuff will be used together with the old one.
For example, replaced libs will be used by programs freshly started, and old
libs will be used for programs already running.
So, the reboot is not strictly required. maybe you may want to restart
some services or applications.
And it always depends on the specific use of the apps.
Say you install a new "tail" command with a security related fix.
Would you reboot? Maybe not. But.... if you have a running tail -f on some
log files where things under external control may be printed?
Then maybe yes. Or.... you just restart the logging script, right?

There are some cases (glibc vulnerability for example) where a reboot
could be a good idea. But, guess what, if you upgrade glibc, the sshd
process will be restarted (!) as that is considered an extremely sensitive
daemon. I may want to restart network facing stuff like httpd, firefox
and something else, but I do not worry too much about the clock applet
currently running the unfixed glibc.

(The iwl Intel driver forced me to reboot my laptop after more than 150 days
and I had really bad words in my mind for Intel and their buggy code;
my work session was incredibly complex and useful to me... I hate reboots).

-- 
   Roberto Ragusa    mail at robertoragusa.it