[CentOS] re-install package

[Scott Silva]

on 4-16-2009 12:10 AM D Tucny spake the following:
> 2009/4/16 John Thomas
> <gmane-2006-04-16 at jt-socal.com
> <mailto:gmane-2006-04-16 at jt-socal.com>>
> 
>     Scott Silva wrote:
>     > And the right repositories have to be online!
> 
>     Finally, a successful commercial repository.
> 
> 
> It's not without it's problems though, especially when using yum...
> Blindly playing with this repository can be bad for your system's
> health, plenty of care and attention is required...
> 
> The packages require quite a bit of ongoing maintence once installed and
> not all versions are stable... The packages don't tend to carry much
> documentation, the reported requirements are not always accurate and the
> package clean up routines are never complete...
> 
> yum update girlfriend doesn't typically work too well if a prior version
> is already installed, newer versions get installed then a cleanup
> happens afterwards, race conditions exist where the previous version can
> do lots of bad things to your system while both versions are effectively
> installed at the same time... a yum remove girlfriend before a fresh yum
> install girlfriend is recommended... Care should still be taken as yum
> will attempt to honour the package dependancies and other packages such
> as pet, house and car could be removed when trying to remove girlfriend,
> especially if any of those were installed after girlfriend and more so
> if it was requires of the girlfriend package that triggered their
> installation... Typically there are significant system reconfigurations
> required to support each new version... yum reinstall doesn't always
> work too well with girlfriend, the package does tend to leave quite a
> bit of state information in place, even after uninstall, which, if this
> is the cause of the problems, won't be fixed by a reinstall...
> 
> An upgrade of girlfriend to wife exists, it's not cheap though and
> potentially can require some major system reconfiguration to support...
> yum can't really handle this, often getting confused between the option
> of upgrading to wife or updating to a later release of girlfriend... The
> upgrade to wife can be forced in certain situations such as if any child
> packages have been accidentally installed, such as by automatic
> overnight updates...
> 
> With wife installed, yum will let you install additional versions of
> girlfriend, but, this is not a recommended configuration as there are
> some very serious interoperability issues, especially if an installation
> of girlfriend pulls in a child update... In that situation, yum would
> try to upgrade girlfriend to wife, but, as you can't, in a standard
> configuration, have multiple instances of wife and newer versions of
> wife obsolete older versions, the old version would need to be removed,
> the massive number of unresolvable dependancies involved in the that
> would cause yum to crash... The only solution is to use rpm with varying
> force and nodeps options to attempt to get your system functional again,
> though even then, bits of old packages will still be lying around
> consuming resources, especially if child packages exist...
> 
> So, while the packages can work, there is quite a bit of work involved
> in fully integrating them and maintaining them... yum can be used, but,
> it's probably best to exclude them in yum.conf and manually install and
> update the packages where you find necessary, taking great care in
> avoiding conflicts and managing dependancies... The extra care taken in
> doing it manually can really pay off in long term system stability...
> 
Too bad that mastery of the system takes most of one's lifetime, and the
skills aren't easily passed on to future admins. ;-P



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