[CentOS] problems with yum_priorities on CentOS5/RHEL5

[Keith Roberts]

On Tue, 10 Aug 2010, Nick wrote:

> To: centos at centos.org
> From: Nick <oinksocket at letterboxes.org>
> Subject: [CentOS] problems with yum_priorities on CentOS5/RHEL5
> 
> Hello,
>
> Many of you will have read this page, with its (somewhat ambiguous) endorsement
> of yum_priorities:
>
> http://wiki.centos.org/AdditionalResources/Repositories/RPMForge
>
> As I gather has been stated before on the centos list [1], that quote stops
> short of outlining what exactly is wrong with yum_priorities (YP) and why it's
> the best solution.  In fact it goes on to say:
>
>> as of yet, no real world problems have been reported with regard to the
>> 'yum-priorities' plugin
>
> Some (I hope, constructive) comments which might help users of yum/YP to avoid
> surprises:
>
> - The above statement should be altered, since it obviously isn't true
>  (Judging both from comments in [1] and my own experience in [2])
>
> - Perhaps it could explain how YP works and when it doesn't with an example?
>  (I have one you are welcome to copy in [2].)
>
> - Could the above page incorporate, or at least link to the useful information
>  at the bottom of the page here:
>
>  http://wiki.centos.org/PackageManagement/Yum/Priorities
>
> - Could it also mention somewhere quite visible that yum_priorities is not
>  available on RHEL5 so any solutions using YP it will just not work there?
>
>
> I'd also like to know more about why YP cannot be made available on RHEL, but I
> guess this is not the place to ask.
>
> Plus I've noticed a couple of features of yum + YP which aggravate the
> shortcomings - again this is probably not the place, but I'll mention them
> anyway, as a heads-up to other users.
>
> 1. yum check-updates and yum update do *not* warn you of an impending
>    unresolved dependency caused by YP hiding the required package.
>
> It seems the only way to find out is if you go ahead and try and perform the
> update, which potentially leaves you with one or more broken packages.
> This seems a serious flaw that should be fixed.

Not necessarily so.
I use '[root]# yum -y --skip-broken update' and this only 
updates the packages that have no depsolving problems. Any 
packages with problems are left out of the update.

> 2. Not only do higher priority packages totally eclipse lower priorities,
>    whatever version, but yum_priorities also makes it seem like they aren't
>    even present.

Well you can enable all your repos with:

[root]# yum --enablerepo=* --disablerepo=Cmedia5 update (or 
whatever the DVD media repo name is).

I have Centos 5.5, ATrpms, EPEL and remi repos all working 
reasonably well using yum-priorities plugin.

My repo priorites might need looking at, but I have no great 
problems that I'm aware of yet.

Kind Regards,

Keith Roberts

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