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Revision as of 13:54, 22 April 2014



SCL - Software Collections - are popular packaging format above rpm. Let's enable them for Fedora. More details on upstream page.


Current status

  • Targeted release: Fedora 21
  • Last updated: 26. 3. 2014
  • Tracker bug: <will be assigned by the Wrangler>

Detailed Description

My first draft [1] is obsoleted by current state of SCL, Copr... I would keep the SCL workflow simple as possible, which means add one SCL into repository. At start I'd like to add it into Playground repo. If everything goes well, I'd like to add it into main Fedora repository.

Playground repo

1. Build SCL in Copr

2. Add SCL into Playground repo

Fedora main repo

0. Build SCL in Copr (or use existing SCL)

1. Do standard package review

2. Upload packages into git - specific branch based on Fedora version and name of collection. For stable repo we must be able to replicate builds from git repo, which Fedora own.

3. Build SCL in koji or magically add SCL builds from Copr (depends on preference of releng)

SCL living on Copr can be good candidates for inclusion in Fedora. Maintainer of such SCL must be able create Change proposal for his collection. Review of packages in the collection should depend on repository (Playground - almost no rules, Fedora - standard guidelines).

Benefit to Fedora

Cool programs depending on specific version of software can still run on Fedora. We see it often with Ruby (on Rails) projects like Puppet, Cloud projects (Katello, Foreman, OpenShift, OpenStack). All those cool apps can run on any Fedora, which will provide collection for them.

New versions of software can be also packaged as collection and tested it before inclusion into main Fedora repository in case the new version would seem to be to disruptive for rest of the system.

The Fedora Cloud Working Group would like to see this; it represents one of that product's key external needs. (See the Cloud Changelist.)


  • Proposal owners:

0. Approve SCL guidelines by FPC

1. Include one collection into Fedora Playground repository or into main Fedora repository (probably the one wanted by Cloud WG). It might be this one rebuild for Fedora Updates of some gems or addition of other gems might be needed. Review by Cloud projects is needed.

  • Other developers: If SCL is in Fedora, maybe some other project can use it for their work.
  • Release engineering: Magically add SCLs builds into compose or set up koji for SCLs.

Upgrade/compatibility impact

SCL will be safely installed outside of the main system. No conflicts, no updates.

How To Test

For users:

0. Install SCL

1. Run your favourite application on the collection

eg. scl enable ruby193 'foreman'

For developers:

0. Install SCL

1. Create your own application for older version of language (change shebang in your script to /opt/fedora/language/...)

2. run your application eg. scl enable ruby193 'yourapp'

User Experience

Two major use-cases:

  • developers will develop their apps - they will need to change shebang of application for example from /usr/bin/perl to something like /opt/fedora/perl516/usr/bin/perl
  • users of apps, which already depend on SCL, can happily use their app, which is finally working


  • create one SCL
  • co-operate with relengs
    • branches in dist-git
    • modify buildroot
  • FPC ticket

Contingency Plan

  • Contingency mechanism: If something went bad, we could still use Copr repository for providing SCL.
  • Contingency deadline: Beta Freeze
  • Blocks release? No.
  • Blocks product? Yes, it might block Cloud WG if they depend on SCL for their installation.


There will be a process documentation in form of wiki pages. User documentation already exists.

Release Notes