EPEL-8 Production Layout

EPEL-8 Production Layout


  1. EPEL-8 will have a multi-phase roll-out into production.
  2. EPEL-8.0 will build using existing grobisplitter in order to use a ‘flattened’ build system without modules.
  3. EPEL-8.1 will start in staging without grobisplitter and using default modules via mock.
  4. The staging work will allow for continual development changes in koji, ‘ursa-prime’, and MBS functionality to work without breaking Fedora 31 or initial EPEL-8.0 builds.
  5. EPEL-8.1 will look to be ready by November 2019 after Fedora 31 around the time that RHEL-8.1 may release (if it uses a 6 month cadence.)

Multi-phase roll-out

As documented elsewhere, EPEL-8 has been slowly rolling out due to the many changes in RHEL and in the Fedora build system since EPEL-7 was initiated in 2014. Trying to roll out an EPEL-8 which was ‘final’ and thus the way it always will be was too prone to failure as we find we have to constantly change plans to match reality.
We will be rolling out EPEL-8 in a multi-phase release cycle. Each cycle will allow for hopefully greater functionality for developers and consumers. On the flip side, we will find that we have to change expectations of what can and can not be delivered inside of EPEL over that time.
  1. 8.0 will be a ‘minimal viability’. Due to un-shipped development libraries and the lack of building replacement modules, not all packages will be able to build. Instead only non-modular RPMs which can rely on only ‘default’ modules will work. Packages must also only rely on what is shipped in RHEL-8.0 BaseOS/AppStream/CodeReadyBuilder channels versus any ‘unshipped -devel’ packages.
  2. 8.1 will add on ‘minimal modularity’. Instead of using a flattened build system, we will look at updating koji to have basic knowledge of modularity, use a tool to tag in packages from modules as needed, and possibly add in the Module Build System (MBS) in order to ship modules.
  3. 8.2 will finish adding in the Module Build System and will enable gating and CI into the workflow so that packages can tested faster.
Due to the fact that the phases will change how EPEL is produced, there may be need to be mass rebuilds between each one. There will also be changes in policies about what packages are allowed to be in EPEL and how they would be allowed.

Problems with koji, modules and mock

If you are wanting to build packages in mock, you can set up a lot of controls in /etc/mock/foo.cfg which will turn on and off modules as needed so that you can enable the javapackages-tools or virt-devel module so that packages like libssh2-devel or javapackages-local are available. However koji does not allow this control per channel because it is meant to completely control what packages are brought into a buildroot. Every build records what packages were used to build an artifact and koji will create a special mock config file to pull in those items. This allows for a high level of auditability and confirmation that the package stored is the package built, and that what was built used certain things.
For building an operating system like Fedora or Red Hat Enterprise Linux (RHEL), this works great because you can show how things were done 2-3 years later when trying to debug something else. However when koji does not ‘own’ the life-cycle of packages this becomes problematic. In building EPEL, the RHEL packages are given to the buildroot via external repositories. This means that koji does not fully know the life-cycle of the packages it ‘pulls’ in to the buildroot. In a basic mode it will choose packages it has built/knows about first, then packages from the buildroot, and if there is a conflict from external packages will try to choose the one with the highest epoch-version-release-timestamp so that only the newest version is in. (If the timestamp is the same, it tends to refuse to use both packages).
An improvement to this was adding code to mergerepo which allows for dnf to make a choice on which packages to use between repositories. This allows for mock’s dnf to pull in modules without the repositories having been mangled or ‘flattened’ as with grobisplitter. However, it is not a complete story. For DNF to know which modules to pull in it needs to set an environment variable for the platform (for fedora releases it is something like f30 and for RHEL it is el8). Koji doesn’t know how to do this so the solution would be to set it in the build systems /etc/mock/site-defaults.cfg but that would affect all builds and would cause problems for building Fedora on the same build system.


A second initiative to deal with building with modules was to try and take modules out of the equation completely. Since a module is a virtual repository embedded in a real one, you should be able to pull them apart and make new ones. Grobisplitter was designed to do this to help get CentOS-8 ready and also allow for EPEL to bootstrap using a minimal buildset. While working on this, we found that we needed also parts of the ‘–bare’ koji work because certain python packages have the same src.rpm name-version but different releases which koji would kick out.
Currently grobisplitter does not put in any information about the module it ‘spat’ out. This will affect building when dnf starts seeing metadata in individual rpms which says ‘this is part of a module and needs to be installed as such’.

Production plans

We are trying to determine which tool will work better long term in order to make EPEL-8.0 and EPEL-8.1 work.


Start Date End Date Work Planned Party Involved
2019-07-01 2019-07-05 Lessons Learned Smoogen, Mohan
2019-07-01 2019-07-05 Documentation Smoogen
2019-07-08 2019-07-12 Release Build work Mohan, Fenzi
2019-07-08 2019-07-12 Call for packages Smoogen
2019-07-15 2019-07-19 Initial branching Mohan, Dawson
2019-07-22 2019-07-31 First branch/test Dawson, et al
2019-08-01 2019-08-01 EPEL-8.0 GA EPEL Steering Committee
2019-08-01 2019-08-08 Lessons Learned Smoogen, et al
2019-08-01 2019-08-08 Revise documentation Smoogen, et al
2019-09-01 2019-09-01 Bodhi gating turned on Mohan

EPEL-8.0 Production Breakout

  1. Lessons Learned. Document the steps and lessons learned from the previous time frame. Because previous EPEL spin-ups have been done multiple years apart, what was known is forgotten and has to be relearned. By capturing it, we hope that EPEL-9 does not take as long.
  2. Documentation. Write documents on what was done to set up the environment and what is expected in the next section (how to branch to EPEL-8, how to build with EPEL-8, dealing with unshipped packages, updated FAQ)
  3. Call for Packages This will be going over the steps that packagers need to follow to get packages branched to EPEL-8.
  4. Release Build Work. This is setting up the builders and environment in production. Most of the steps should be repeats of what was done in staging with additional work done in bodhi to have signing and composes work
  5. Initial Branching. This where the first set of packages are needed to be branched and built for EPEL-8: epel-release, epel-rpm-macros, fedpkg-minimal, fedpkg (and all the things needed for it).
  6. First Branch Going over the various tickets for EPEL-8 packages, a reasonable sample will be branched. Work will be done with the packagers on problems they find. This will continue as needed.
  7. EPEL-8.0 GA Branching can follow normal processes to get done.
  8. Lessons Learned. Go over problems and feed into other groups backlogs.
  9. Documentation Update previous documents and add any that were found to be needed.


Start Date End Date Work Planned Party Involved
2019-07-01 2019-07-05 Lessons Learned Fenzi, Contyk, et al
2019-07 ??? Groom Koji changes needed ???
2019-07 ??? Write/Test Koji changes needed ???
2019-07 ??? Non-modular RPM in staging ???
2019-07 ??? MBS in staging ???
2019-08? ??? Implement Koji changes? ???
2019-08? ??? Implement bodhi compose in staging? ???
2019-09? ??? Close off 8.1 beta ???
2019-09? ??? Lessons learned ???
2019-09? ??? Begin changes in prod? ???
2019-10? ??? Open module builds in EPEL ???
2019-11? ??? EPEL-8.1 GA EPEL Steering Committee
2019-11? ??? Lessons Learned ???
2019-11? ??? Revise documentation ???

EPEL-8.1 Production Breakout

This follows the staging and production of the 8.0 with additional work in order to make working with modules work in builds. Most of these dates and layers need to be filled out in future meetings. The main work will be adding in allowing a program code-named ‘Ursa-Prime’ to help build non-modular rpms using modules as dependencies. This will allow for grobisplitter to be replaced with a program that has long term maintenan


Update on EPEL-8 Status

Update on EPEL-8 Status

Where is EPEL-8? (tl;dr:)

  1. Getting koji to work smoothly with modules has been hard. A multi-level fix has had to be worked to get it working in staging.
  • Needed a way to split out default modules to deal with koji merge options. Grobisplitter was written to do this
  • Koji needed further patching to deal with src.rpms with same NVR but different targets (some python2 and python3 come from same src.rpm but were built in different times).
  • DNF reposync from RHEL-7 would delete the wrong files if you tried the --newest (fixed.)
  • DNF does not know how to reposync modules if it is not the local arch.
  1. Code Ready Builder is not always in sync with packages in main trees. If you need a -devel and it isn’t in CRB, then you have to wait until it is there to build something.
  2. As a couple of fixes landed in mergerepo and koji, we are re-evaluating how we do builds in the next stage of building.


In May of 2019, Red Hat released their 8.0 release of Red Hat Enterprise Linux (RHEL). Usually, the Extra Packages for Enterprise Linux (EPEL) group would have a beta available at that time or sooner. With RHEL-8, it has taken a lot longer to get things rolling.

Repository Changes

EPEL packages are built inside of the Fedora Projects’ build infrastructure. This is done by downloading the packages from Red Hat’s public Content Delivery Network (CDN), and then having the Fedora artifact build system (koji) use the release as an external build channel. Koji looks at packages in a different way than other build commands like ‘mock’ do. Where mock is meant to just build packages, koji is designed about auditing the entire lifecycle of a package. In other words, if you want to know how a package in Fedora 12 was built and all its children interacted over time in the buildroots… you can do that with enough work and the koji databases. With mock you have a couple of log files which tell you what was pulled into a buildroot but how those were built would require you finding their log files, etc etc. A developer can also download those packages and look at them to see what was in them and how they were built.

The strength of koji is that you can have a credible chain of builds to know where things came from. However this doesn’t work too well with building packages for EPEL where koji doesn’t know where the RHEL kernel came from. Koji uses mergerepo to look at the external packages provided, determines the src.rpm they would come from and determines what the latest version it would use from each. From this it creates a ‘buildroot’ which it will use to build packages from. This has worked pretty well for building packages from RHEL-5,6, and 7. The major downside has been where someone built a package with the same src.rpm name which koji then decides is the master no matter if a newer version shows up in RHEL.

This all changed with modularity. Koji really only has a rudimentary idea of rpms and repositories… it has zero idea about modules and the rules it has used to determine what an external package is are thrown out with modules.
  1. Packages with different names may come with from the same src.rpm. In RHEL-8 many python27 and python36 packages have the same parent src.rpm but were in different build times. Koji’s standard repo comparison mode will choose one or the other.
  2. Packages may have the same names-version-releases but were built in different module streams (say perl-5.26 and perl-5.24) Koji would then choose a package depending on whatever had the largest src.rpm which meant it could try to build a buildroot with perl-5.24 perl modules but perl-5.26 as the master perl.
If a developer uses mock to build a package with default repositories, mock calls dnf which knows about modules and does the right thing. In the case where you want it to do the ‘wrong’ thing you can also over-ride mock to do that. With koji, further tools are needed to make this work. If you are building a new module, then the Modular Build System (MBS) sits on top of koji and tells koji what to do. It will look at the module yaml file and turn on/off various modules so that it can build in what is needed. To build non-modular packages, other fixes are needed. One of these is called Ursa-Major which was a set of scripts to pull in needed data from a third database and pull things in as needed. However, this was not adopted in Fedora for general use so the EPEL group looked for something different.

The temporary solution written by Patrick Uiterwijk is called grobisplitter (https://github.com/puiterwijk/grobisplitter) which relies on the fact that modules are virtual repositories embedded in a master repository. Grobisplitter takes this fact, and uses it to break out ‘real’ repositories for each module. So the RHEL-8 repository will look like:


In the above, each of those names is the module name, and grobisplitter would then put the appropriate files in each sub repository. The problem with this version is that we end up with multiple repositories with some of them being ‘non-default’ modules. Building against a non-default module causes problems for someone trying to install that package. It would replace packages from a different module than was wanted. Changes to grobisplitter were made at https://github.com/smooge/grobisplitter to allow only default modules to be published.

From this we were able to start deploying a devolved tree in the Fedora staging koji (https://koji.stg.fedoraproject.org/) The first set of fixes needed was to make it so koji could work with multiple artifacts coming from the same src.rpm. Instead of using the standard mode for resolving differences, we import RHEL-8 repositories with a bare mode which is supposed to use external repository data to determine what should be pulled in. However, we found that koji still gets confused if multiple versions of a package are in the repo data. Say your repository contains both glibc-*-2.1-2 and glibc-*-2.2-2. Koji would pull in glibc-devel-2.1-2 and try to match it against glibc-2.2-2. This of course caused builds to fail.

At first the fix looked to be having the reposync from the CDN pull only the latest data. However we ran into problems with either the RHEL-7 or RHEL-8 reposync deleting data we wanted to keep depending on the options used. Part of this was due to module data and part of it was due to some bugs in dnf’s reposync with other architectures. At this point, it looked like one of two things needed to be done.

One, grobisplitter needs to learn about package order and pull in just the latest package into a non-modular repo. Two, another layer of indirection is needed where after we split out all the repositories we use reposync again to just pull from the grobisplit repositories. In this case we do so with a -n and only have the latest packages. The second option seemed easier to pursue as most of the grobisplitter toolkit should become irrelevant when the next generation of Ursa-Major comes out.

Code Ready Problems

We ran into our next major problem with RHEL-8 repositories when we found that -devel and -lib rpms in Code Ready Builder were not always in sync with their parent packages in BaseOS/AppStream. This means that if your build is wanting kernel-devel and the BaseOS is 4.9-11 but the CRB version is 4.9-10 then koji has no way to supply the dependency for you. The major culprit currently is that the virt module has had multiple updates but the virt-devel module has not had any updates.

Build Over View

  1. RHEL-8 packages are reposync from cdn onto infrastructure.fedoraproject.org nfs directory.
  2. grobisplitter runs on grobisplitter01.phx2.fedoraproject.org to break out each module into repositories in a $date/$arch/$repos layout.
  3. createrepo is run on $date/$arch
  4. a symbolic link is set to $date staged
  5. reposync -n -d is run against staged/$arch to latest/$arch
  6. createrepo is run on latest/$arch
  7. koji points to latest/$arch
  8. packages can be built
  9. packages can be signed
  10. bodhi and other items do their parts
  11. we compose
  12. profit?

What Are The Next Steps?

Currently we are looking to have our internal beta done by July 1st. At that point, we will work on documenting what we have done, and re-implementing the tool changes in production. At which point, developers will be able to make branch requests to releng to make packages available and builds should start flowing. From that we will probably find new things which will need fixes in either spec files or build infrastructure.

A GANNT chart of our current production plan is provided below.


EPEL Proposal: Steve Gallagher's EPEL 8 Branch Strategy

Stephen Gallagher's Better Proposal for EPEL branching

So earlier this week I wrote up a proposal for EPEL-rawhide which was to go over various ideas the EPEL steering committee has been kicking around for a bit. This was to try and work into how to branch for EPEL-8 and also how to deal with https://fedoraproject.org/wiki/EPEL/Changes/Minor_release_based_composes and https://fedoraproject.org/wiki/EPEL/Changes/Release_based_package_lifetimes During the meeting it was clear that my strawman didn't have much in it, and needed more thinking. Thankfully Stephen Gallagher looked into the meeting and came up with some ideas that he wrote up and proposed to the list.. I recommend that you read the document and updates if you are interested in how branching in EPEL could work with EL7 and EL8.


EPEL Proposal: EPEL Master branch AKA Rawhide



This proposal has been superseded by Stephen Gallagher's excellent wagontrain post. I will put it as a separate post next.

tl; dr:

In order to allow for the ability for faster availability of packages, add rawhide branches for EPEL-7 and EPEL-8. These branches would allow developers to build new packages they aren't sure are ready for either EPEL-N or EPEL-N-testing, and would allow for faster rebuilds of newer features when RHEL has a large feature change.

The Longer Story

In the past 6 months, EPEL has had to have two major changes in its builds which were made harder by the way EPEL is currently built. The first one was with changes in RHEL-7.6 which dropped some packages and changed some others ABI's. This required a rebuild of a lot of packages, but there was no way we could do a find and fix before we did a 'flag-week' of rebuilds with Troy Dawson and others doing lots of Proven Packager fixes and rebuilds.

The second one was with the python36 move which also took a large amount of time and still has little problems showing up here and there. In a similar fashion, updates-testing had to be used as a rawhide for packages which made building and testing hard for things not doing this change.

A third problem showed up when Troy was cleaning out packages in EPEL-6 and 7 testing repos which had been there for years. The packagers were using this for putting things they felt were too unstable for EPEL due to unstable API's so they could either iterate quicker or not break existing users. The problem is that these packages might accidentally get  promoted by someone seeing that the packages are tested but wasn't pushed. Having a separate tree for these unstable packages needed a different thinking.

While doing a review of these two exercises, the EPEL steering committee came up with various ideas.. and I believe Kevin Fenzi brought up adding a rawhide as an easier fix than some of my more convoluted branch every release (aka epel-7.6, epel-7.7, epel-7.8). In this new scheme, we would have the following branches: el6, epel7, epel7-master, epel8, epel8-master.

A possible work flow could be the following:
  1. Packages when branched for EL7 or EL8 would get branched into the epel-M-master tree where they could have builds made against the latest RHEL. 
  2. When Red Hat released a new beta (RHEL-M.N-beta), Fedora Infrastructure would download it and set it up so koji could find it. as EPEL-M-Master (or properly bikeshed name). A mass update and rebuild would then be done against all packages in EPEL-M-Master. Breakfixes and testing can be done.
  3. When the General Availability of RHEL-M.N occurs, EPEL will make a copy of EPEL-M.(N-1), EPEL-M.(N-1)-updates and EPEL-M.(N-1)-updates-testing in /pub/archive/epel/M/M.(N-1)/.
  4. An after Red Hat releases the General Availability of the RHEL-M.N release, 
    1. if the version in master is newer than the version in branch, the master version will be checked into the branch. (This step is probably the most problematic and needs more work and thinking by people).
    2. packages which meet certain criteria will then be promoted to EPEL-M with a new compose of EPEL-M.N and an empty EPEL-M.N/updates and EPEL-M.N/updates-testing.
  5. The packager can do updates and fixes to packages in the EPEL-M branch 
  6. The finishing up of clean up the archives can occur.
This is a preliminary proposal which needs a lot more work and resource commitments in changes to tooling and documentation. I am bringing this up as something I would like to get done as part of revamping EPEL this summer, but I also need feedback and help.

EPEL Proposal: Removal of PPC64 (Not PPC64le) in 2019-06-01


EPEL is looking to put its EL6 and EL7 branches of PPC64 into archives by 2019-06-01. This is due to the fact that Fedora no longer builds for the PPC64 big-endian architecture.

The long story

As of the EOL of Fedora 28, the Fedora Project no longer supports or builds packages for the big endian Power64 (or ppc64) architecture. Kevin Fenzi went over this in his blog article, but I wanted to go over it again. I realize this is short notice so extra steps need to be done.

The Fedora Project uses Fedora Linux on its builders which is useful for bringing on new architectures, and for getting new features which RHEL does not have yet. However it means that when an OS is End of Lifed, it no longer gets security updates, software improvements, or similar fixes. We could try and stand up an EL7 builder but it would require reworking both tools and scripts that are expecting an F28 world (python3, various newer libraries and scripts, different API's, etc). That would take a while to rework everything back and then continual work of keeping this builder in line with whatever EL8/F30+ world we move to in the coming months. Secondly, this would cut out a limited resource. We only have so many PPC8 systems which we can run PPC64 virtual machines on. The virtual machines can either build an EPEL package or a Fedora <29 be="" but="" down="" epel.="" just="" limiting="" p="" package="" this="" to="" we="" would="">
In the end, the number of PPC64 users are not that great. We have an average of 90 systems per day checking in with many more PPC64LE systems. I think most of the PPC64 users would be able to get stuff from archives just as well.

How do I get my stuff

The builds for EL6.10 and EL7.6 will be archived to /pub/archives/epel/7/7.6 and /pub/archives/epel/6/6.10 this week. We may need to roll out an updated epel-release which will point this architecture to that tree. We will then remove the builders from Fedora and stop building for it. In early July I will remove the remaining trees from /pub/epel and put in redirects to the archives.


Final 503 addendum

mirrorlist 503's for 2019
This is a graphical shape of the amount of 503's we have had in 2019. The earlier large growth in January/February have dropped down to just one web-server which is probably underpowered to run containers.  We will look at taking it out of circulation in the coming weeks.


EPEL: Python34->Python36 Move Happening (Currently in EPEL-testing)

Over the last 5 days, Troy Dawson, Jeroen van Meeuwen, Carl W George,  and several helpers have gotten nearly all of the python34 packages moves over to python36 in EPEL-7.  They are being included in 6 Bodhi pushes because of a limitation in Bodhi for the text size of packages in an include.

The current day for these package groups to move into EPEL regular is April 2nd. We would like to have all tests we find in the next week or so also added so that the updates can occur in a large group without too much breakage.


Please heavily test them by doing the following:

Stage 1 Testing

  1. Install RHEL, CentOS, or Scientific Linux 7 onto a TEST system.
  2. Install or enable the EPEL repository for this system
  3. Install various packages you would normally use
  4. yum --enablerepo=epel-testing update
  5. Report problems to epel-devel@lists.fedoraproject.org

Stage 2 Testing

  1. Check for any updated testing instructions on this blog or EPEL-devel list.
  2. Install RHEL, CentOS, or Scientific Linux 7 onto a TEST system.
  3. Install or enable the EPEL repository for this system
  4. yum install python34
  5. yum --enablerepo=epel-testing update
  6. Report problems to epel-devel@lists.fedoraproject.org

Stage 3 Testing

  1. Check for any updated testing instructions on this blog or EPEL-devel list.
  2. Install RHEL, CentOS, or Scientific Linux 7 onto a TEST system.
  3. Install or enable the EPEL repository for this system
  4. yum install python36
  5. yum --enablerepo=epel-testing update
  6. Report problems to epel-devel@lists.fedoraproject.org
This should cover the three most common scenarios. Other scenarios exist and will require some sort of intervention to work around. We will outline them as they come up.

Many Many Thanks go to Troy, Jeroen, Carl, and the many people on the python team who made a copr and did many of the initial patches to make this possible.