Oracle Linux – Oracle-epel Vs Epel – Dnf Priority

Home » CentOS » Oracle Linux – Oracle-epel Vs Epel – Dnf Priority
CentOS 4 Comments

I’d like to run this by you guys and get your opinion.

For those of us who are considering moving to Oracle Linux (or at least doing some experimenting with it), I just had an idea for dealing with the fact that the oracle-el-epel apparently doesn’t have all of the packages that are in the fedora-el-epel that we all know and love.

It makes sense to me to use the oracle epel with OL to the greatest extent possible simply because it’s part of OL.

To get around the missing package issue, what about setting up both oracle-epel and fedora-epel, and then using the dnf priorities to pick the stuff from oracle-epel first and if it’s not there then grab it from fedora-epel.

One issue that I can see (though it may not be an actual issue) is the way the priorities setting works:

QUOTE:
priority
integer
The priority value of this repository, default is 99. If there is more than one candidate package for a particular operation, the one from a repo with the lowest priority value is picked, possibly despite being less convenient otherwise (e.g. by being a lower version). END OF QUOTE

By setting fedora-epel to a lower priority, the if a package we want is only in fedora-epel, we’ll grab it from there. But if that package has a dependency on another package version X that can be found in fedora-epel and for some reason oracle-epel supplies only package version X-1, what happens then? Is dnf smart enough to pick the higher-versioned (and required) package from fedora-epel even though it has a lower priority.

I’ll try to explain that again.

I want to install Foo, which is only in fedora-epel.

Foo requires Bar version 2.0.

Bar 2.0 exists in fedora-epel, but oracle-epel has only Bar version 1.0.

What happens then? Does dnf see that Foo requires Bar-2.0 and get it from fedora-epel even though it has a lower priority?

4 thoughts on - Oracle Linux – Oracle-epel Vs Epel – Dnf Priority

  • Having done this for years.. choose one or the other. Do NOT mix the two. You will end up with heartache and sleepless nights trying to figure out why things are broken. If you are lucky it is something easy like an update is broken because the missing EPEL package wants a library that the OEL has an older version of. In other cases it is the same thing but the soname was good enough to make rpm think it would work.

    I say this as a former EPEL package leader.. either use Oracle EPEL and figure out how to interact with them to get their rebuilds done faster or do the same with Fedora EPEL. Priorities and similar filtering tools work well enough if you have focused repositories where small sets may overlap but you want X to take over from Y. In the case of nearly 1:1 repos, you will end up with it working 95%-99% of the time and then burning down the house.

  • Le 14/12/2020 à 19:41, Frank Cox a écrit :

    The Yum Priorities plugin (package yum-plugin-priorities) would be nice to have, but unfortunately it seems to have disappeared. I’ve used this quite extensively over the last decade. Whenever I have to use a third-party repo that’s a potential threat to the official repos, I’m setting it up with priority=10 or something just to be on the safe side.

    This has always worked like a charm.

    Cheers,

    Niki

    —
    Microlinux – Solutions informatiques durables
    7, place de l’église – 30730 Montpezat Site : https://www.microlinux.fr Blog : https://blog.microlinux.fr Mail : info@microlinux.fr Tél. : 04 66 63 10 32
    Mob. : 06 51 80 12 12

  • Like all system administration, there are a lot of corner cases which come up when you have nearly the same repositories. It was nearly a daily occurence in #epel and #CentOS-devel of someone, somewhere having a problem with DAG and EPEL even with the appropriate priorities. The more overlap of the package sets, the more likely something would break in a way you only found 2 to 3 days after you updated.

    There is also a level of system administration skill to make it work seamlessly which we forget. Most of the people running into issues were people who had followed someone else’s advice in an irc or mailing list but did not really understand what priorities or similar tools did. People who do know tend to also have test systems and roll out methodologies which are second nature versus ‘yum -y update’ cron jobs on a fleet of systems.

    —
    Stephen J Smoogen.

  • …

    That’s pretty much what I was afraid of.

    I guess the smart move would be to run OL along with the fedora-epel and not bother with the oracle-epel then.