explanation of yum.cron + a little frustration.

[Erik Hemdal]

> From: Jason L Tibbitts III <tibbs at math.uh.edu>
> Subject: Re: explanation of yum.cron + a little frustration.
> To: akonstam at trinity.edu
> Cc: For users of Fedora Core releases <fedora-list at redhat.com>
> Message-ID: <ufaslxc8cv8.fsf at epithumia.math.uh.edu>
> Content-Type: text/plain; charset=us-ascii
> 
> >>>>> "a" == akonstam  <akonstam at trinity.edu> writes:
> 
> a> Look, I appretiate that people answer my questions but why won't
> a> some on tell me the answer to this question.
> 
> That's a great way to elicit killfile additions instead of help, but
> I'll persist.
> 
> a> I asume the last line in the script does a yum update.
> 
> To be clear, I believe you refer to this line:
> 
> /usr/bin/yum -R 10 -e 0 -d 0 -y shell /etc/yum/yum-daily.yum
> 
> A quick perusal of the yum manual page tells what the arguments mean:
> 
> -R 10  -- wait a random amount of time, up to ten minutes
> -e 0   -- print only critical errors
> -d 0   -- turn off debugging
> -y     -- assume a "yes" answer to any prompts
> shell /etc/yum/yum-daily.yum
>        -- process yum commands from /etc/yum/yum-daily.yum
> 

To be fair to Aaron, who is a pretty helpful guy in these parts, the man
pages do not describe what 'shell' does. It is not included as one of
the arguments to yum or one of its commands. Nor does the info page,
which looks like the same information.  I think that's the crux of his
question.

yum --help

includes 'shell' as the last option in a long line of BNF options, but
does not explain what it does either.  

To understand, you must run 'yum shell' and ask for help inside it.  Not
easy to do if you don't know the shell is there.  And it is not readily
apparent that yum includes its own shell; at first I thought that since
there's no shell mentioned in the man page, that yum was invoking the
Python shell to provide arguments. But 'ts run' isn't in the man pages
either as an argument or yum command. Like Aaron, I was seriously
mystified at all of this.  I only figured it out by typing the command
at the bash prompt and watching (open-jawed) as yum offered me a shell!

Although I can understand the usage of a shell for yum interactively, I
agree with Aaron that it's very complicated to use it for yum-daily.yum.
Don't blast him on this question.

The point has been made in another post that this allows sysadmins the
ability to modify the overnight yum update. Sounds good, but what else
would you do besides installing updates or populating a local repo?  Yum
can do many things, but usually I want to be there when it does them.

If anyone has a suggestion, or better, an example, for how you could
profitably modify yum-daily.yum, I would be grateful to see it.

Erik