I originally asked this as part of another message in May, but maybe 
no-one read past my driveling to this part -- well no-one replied 
anyway... :-)

--start-quote--
BTW is the installonlyn yum plugin available (as part of some package 
somewhere)?

   http://people.redhat.com/~katzj/installonlyn.py

   #   A plugin for yum which only leaves n 'kernel' packages installed instead
   #   of infinitely doing installonly

I found a thread on a Centos mailing list suggesting it was part of yum-utils 
but that was for Centos-4 anyway.

   http://lists.centos.org/pipermail/centos-devel/2006-August/002361.html

FC 5 and 6 appear to have this functionality included in the base yum package 
and so does the yum in TUV-el5 if you see what I mean.

$ rpm -qlp yum-3.0.1-5.el5.src.rpm | grep installonlyn
installonlyn.py

I don't know if it is *enabled* by default in those releases though!
--end-quote--

Anyway after that I noticed that SL45 (at least) has yum-installonlyn 
mentioned in the releasenotes -- built as part of yum-utils I think.

I think I understand how it got dropped (not part of SL's yum, but is in 
TUV's yum, so missing from their yum-utils), though I may have missed 
something more subtle.

Anyway to cut a long story slightly shorter I gave in and made the trivial 
rpm for it and it does seem to work...

$ yum update
...
Loading "installonlyn" plugin
...
 ============================================================================
  Package                 Arch       Version          Repository 
Size
 ============================================================================
Installing:
  kernel                  i686       2.6.18-8.1.8.el5  sl-testedbits      12 M
  kernel-devel            i686       2.6.18-8.1.8.el5  sl-testedbits     4.5 M
Updating:
  kernel-headers          i386       2.6.18-8.1.8.el5  sl-testedbits     726 k
  xorg-x11-xfs            i386       1:1.0.2-4        sl-testedbits      68 k
  xorg-x11-xfs-utils      i386       1:1.0.2-4        sl-testedbits      27 k
Removing:
  kernel                  i686       2.6.18-8.1.4.el5  installed          34 M
  kernel                  i686       2.6.18-8.1.3.el5  installed          34 M
  kernel-devel            i686       2.6.18-8.1.4.el5  installed          14 M
  kernel-devel            i686       2.6.18-8.1.3.el5  installed          14 M
...

without something like this my /boot would be full after another 10-15 
kernel updates...

$ rpm -qil yum-installonlyn
Name        : yum-installonlyn             Relocations: (not relocatable)
Version     : 0.92                              Vendor: (none)
Release     : 1.sl5x                        Build Date: Thu Jul 19 00:30:49 2007
Install Date: Thu Jul 19 00:33:01 2007      Build Host: deluxe.damtp.cam.ac.uk
Group       : Development/Tools             Source RPM: yum-installonlyn-0.92-1.sl5x.src.rpm
Size        : 7591                             License: GPL
Signature   : DSA/SHA1, Thu Jul 19 00:32:10 2007, Key ID 04a6250b6173bb82
URL         : http://people.redhat.com/~katzj/installonlyn.py
Summary     : Yum plugin to only keep n 'kernel' packages
Description :
A plugin for yum which only leaves n 'kernel' packages installed
instead of infinitely doing installonly
/etc/yum/pluginconf.d
/etc/yum/pluginconf.d/installonlyn.conf
/usr/lib/yum-plugins
/usr/lib/yum-plugins/installonlyn.py
/usr/lib/yum-plugins/installonlyn.pyc
/usr/lib/yum-plugins/installonlyn.pyo

Maybe it will be of use to some others...

-- 
Jon Peatfield,  Computer Officer,  DAMTP,  University of Cambridge
Mail:  [log in to unmask]     Web:  http://www.damtp.cam.ac.uk/