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.
On Tue, 10 Aug 2010, Nick wrote:
To: centos@centos.org From: Nick oinksocket@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.
- 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.
- 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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On 10/08/10 17:52, Keith Roberts wrote:
- 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.
Ok, but this isn't a solution, if the broken dependency is related to something you care about. It just the easiest possible resolution to implement.
- 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.
I do wonder why the problem I've had isn't seen more often, as perl-Module-Install (the package which requires the eclipsed package, perl-Archive-Tar) is quite a common dependency of Perl packages.
However, whether this problem manifests itself would depend on what packages are installed, not just which repositories are enabled. Maybe you're just lucky (or I'm unlucky), and don't need perl-Module-Install.
Cheers,
N
On Wed, 11 Aug 2010, Nick wrote:
To: centos@centos.org From: Nick oinksocket@letterboxes.org Subject: Re: [CentOS] problems with yum_priorities on CentOS5/RHEL5
On 10/08/10 17:52, Keith Roberts wrote:
- 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.
Ok, but this isn't a solution, if the broken dependency is related to something you care about. It just the easiest possible resolution to implement.
- 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.
I do wonder why the problem I've had isn't seen more often, as perl-Module-Install (the package which requires the eclipsed package, perl-Archive-Tar) is quite a common dependency of Perl packages.
However, whether this problem manifests itself would depend on what packages are installed, not just which repositories are enabled. Maybe you're just lucky (or I'm unlucky), and don't need perl-Module-Install.
Cheers,
N
I don't seem to be using that package:
Available Packages Name : perl-Module-Install Arch : noarch Version : 0.92 Release : 1.el5.rf Size : 156 k Repo : rpmforge Summary : Standalone, extensible Perl module installer URL : http://search.cpan.org/dist/Module-Install/ License : Artistic/GPL Description: Module::Install is a standalone, extensible installer for Perl : modules. It is designed to be a drop-in replacement for : ExtUtils::MakeMaker, and is a descendent of CPAN::MakeMaker.
Kind Regards,
Keith Roberts
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-
Keith Roberts -
Nick