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.
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.
When a dependency is eclipsed, yum queries with --showduplicates will tell you there *is* no package which satisfies the missing requirement, making it look like the repository is broken.
You have to disable all plugins to get the correct answer:
$ yum --showduplicates --noplugins list perl-Archive-Tar
Finally, I'd like to ask if there have been any developments, or new advice anyone can offer on the topic, since November 2009?
Thanks,
Nick
1. http://thread.gmane.org/gmane.linux.centos.general/86563
2. An example of when yum_priorities bites included here: http://www.noodlefactory.co.uk/~nick/wu-lee/Notes/YumPrioritiesPitfalls
Comments welcomed.