[Centos] Re: cron job madness

Wed Jul 7 01:38:57 UTC 2004
John Newbigin <jn at it.swin.edu.au>

I am not trying to start a flame war here, just share my thoughts on 
what I think a responsible system administrator should do before 
installing new software on a live server.

Rick Graves wrote:

> Hey,  
>>check-update sounds better than putting yum update
> in a cron job.  Only a mad man would do that!  
> Are the cAos and CentOS releases THAT BAD?
I am not sure what you mean by THAT BAD.  yum in centos-2 comes with a 
cron script which, when enabled will run "yum update" every day.  This 
IMHO is bad so I made sure that it is not enabled by default.
>>Much better to run a daily cron which rsyncs your
> local patch repository.
> So must one have your own local repository to avoid
> being labeled as a madman?  
I said better, not must.  I recommend a local repository if you have 
more than one machine which will require the patches installed.  I 
recommend having more that one machine so you can test the patches on a 
test box and not your live server.
> In which one of the RedHad reference books can I find
> this?
Just because RedHat did not write a book about it, does not make it bad. 
  RedHat actually wrote a product "Proxy and Satellite Servers".

And here are some of the reasons for not installing rpm updates without 
1. back up your config files.  Even the best spec files can have 
mistakes.  If you have modified a file which is not flagged as a config 
file then you might lose all your changes.  Spend 10 seconds and tar up 
/etc (and perhaps run rpm -V and see if there is anything else which 
might have changed)
2. unwanted side effects.  Some packages can create annoying side 
effects, particularly ones which have cron jobs.  sa and mrtg have been 
known to do this.
3. bugs.  Many redhat packages contain buggy software.  Often the 
updates introduce more bugs than they fix.  stunnel 3.26 for example 
appears to work at first but does not work reliably.  Mozilla has 
cosmetic bugs which means that some users lose their mozilla icons. 
Small but can still cause users to ring and complain at 2:00 in the morning.

Of course, the thing which makes a good administrator (or any other 
role) is the ability to evaluate other peoples suggestions and decide 
for themselves what they should do.


> Just curious.
> Rick
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John Newbigin - Computer Systems Officer
School of Information Technology
Swinburne University of Technology
Melbourne, Australia