CentOS - Feb 2018 - Going back to a minimal system : strange problem

Hi,

Some time ago I wrote a little script elaguer.sh ("?laguer" means
"to
prune") which simply removes all packages that are *not* part of a
minimal installation.

First I created a list of packages that make up a minimal CentOS
installation. On a fresh install, I would do something like this:

# rpm -qa --queryformat '%{NAME}\n' | sort > minimal.txt

Here's the resulting list of packages. I added a comment on top:

https://github.com/kikinovak/centos-7-server-lan/blob/master/config/pkglists/minimal.txt

And here's the script to prune the installation, e. g. remove everything
that's not on the list.

https://github.com/kikinovak/centos-7-server-lan/blob/master/elaguer.sh

This script worked perfectly for some time. But now it seems like
something has changed somewhere under the hood. Because when I run it
now, the script fails at the final package removal stage. One curious
detail: it seems like it tries now to remove 'yum' and
'systemd', so
'yum' exits with an error. But it didn't do that before, so my guess
is
either 'yum' behaves differently now, or package dependencies are
calculated differently. Anyway, I'm a bit clueless here.

Any suggestions?

Cheers from the freezing South of France,

Niki
-- 
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On 02/26/2018 06:03 AM, Nicolas Kovacs wrote:
> This script worked perfectly for some time. But now it seems like
> something has changed somewhere under the hood. Because when I run it
> now, the script fails at the final package removal stage.

I would hazard to guess that the flaw is simply that from time to time, 
packages are added to the minimal install as a side effect of adding in 
new dependencies.? If you had a minimal install and simply ran "yum 
update", you would periodically see yum report that it would install new 
packages for dependencies, in addition to the updates.? As that is the 
case, you will need to update your minimal package list immediately 
before running the pruning script in order to avoid removal of core 
packages.

I wonder if it might work to use a yum transaction, in which you first 
remove everything (which avoids the need for the list entirely), then 
adds the minimal package set, and then commits the transaction...

Le 26/02/2018 ? 16:12, Gordon Messmer a ?crit :
> I would hazard to guess that the flaw is simply that from time to
> time, packages are added to the minimal install as a side effect of
> adding in new dependencies.  If you had a minimal install and simply
> ran "yum update", you would periodically see yum report that it
would
> install new packages for dependencies, in addition to the updates.
> As that is the case, you will need to update your minimal package
> list immediately before running the pruning script in order to avoid
> removal of core packages.
That was my thought also, but the only difference between a fresh
installation of CentOS 7.4 and the updated version as of today is the
replacement of grub2 by grub2-tools, so that's not the reason apparently.
> 
> I wonder if it might work to use a yum transaction, in which you
> first remove everything (which avoids the need for the list
> entirely), then adds the minimal package set, and then commits the
> transaction...
I only have a very vague notion of yum transactions, so I'll look into
that and report back.

Cheers,

Niki

-- 
Microlinux - Solutions informatiques durables
7, place de l'?glise - 30730 Montpezat
Site : https://www.microlinux.fr
Blog : https://blog.microlinux.fr
Mail : info at microlinux.fr
T?l. : 04 66 63 10 32

Le 26/02/2018 ? 16:12, Gordon Messmer a ?crit?:
> I would hazard to guess that the flaw is simply that from time to time,
> packages are added to the minimal install as a side effect of adding in
> new dependencies.? If you had a minimal install and simply ran "yum
> update", you would periodically see yum report that it would install
new
> packages for dependencies, in addition to the updates.? As that is the
> case, you will need to update your minimal package list immediately
> before running the pruning script in order to avoid removal of core
> packages.
OK, I found the culprit. A simple mix-up in my minimal package list. The
file I used was the old one from a CentOS 7.2 installation. A simple
'diff' showed me where I was wrong.

I updated the minimal package list, and everything works like a charm again.

Cheers,

Niki

-- 
Microlinux - Solutions informatiques durables
7, place de l'?glise - 30730 Montpezat
Site : https://www.microlinux.fr
Blog : https://blog.microlinux.fr
Mail : info at microlinux.fr
T?l. : 04 66 63 10 32