From Fedora Project Wiki

Better Erlang Support


Update Erlang/OTP to R17, and improve Erlang integration with the rest of Fedora.


Current status

Detailed Description

Erlang in Fedora is already in a good shape. However we can do better since there are a number of annoying shortcomings and issues. Just a few of them:

  • Fedora partially enabled Ellyptic Curve Crypto recently, but we still provide Erlang with EC disabled completely. That's because there is no way to enable just a few EC in the current Erlang version.
  • Erlang<->systemd interaction is in a quite poor state currently.
  • There is no way to install "headless" Erlang. Every Fedora Erlang user have to install graphical libraries even if (s)he doesn't want to use GUI on the target machine.
  • Every daemon written in Erlang has its own logging solution which doesn't use neither syslog nor Journald.
  • Erlang packaging is quite complex and undocumented mostly.

In order to address all these issues we should do the following:

Benefit to Fedora

  • Users will get initial EC support in Erlang. We still can't enable EC fully but at least we will enable some EC curves.
  • Users will have less issues caused by poor systemd and EPMD integration (lost node names during other Erlang daemons restarts etc).
  • Users will get centralized unified logging from all Erlang applications
  • Users won't have to install X11-related libraries if they don't want to.
  • Packagers won't see scary rpmlint messages regarding marking arch-independent package as arch-dependent one.
  • Packagers will spend less time on packaging Erlang software for Fedora.


  • Proposal owners:
    • We must rebuild Erlang R17 and submit it to build-overrides.
      • We have to rebuild all the packages listed below in the Dependencies section.
    • DONE A necessary *.socket unit must be added to erlang-erts to enable EPMD socket activation.
      • Every Erlang daemon's systemd unit must require epmd.socket.
      • Allow EPMD implementation switching - Erlang is about choice!
    • We need to fill new review request for erlang-ejournald
      • We have to fill new review request for erlang-lager_journald_backend
    • We have to patch out GUI parts and provide a way to tell user what to do in order to enable this functionality.
    • Add another default directory to look for Erlang *.beam files.
    • Every Erlang package must require erlang-rpm-macros.
    • Riak has growing Bugzilla backlog. We have to address all of these issues.
  • Other developers: N/A
  • Release engineering: N/A
  • Policies and guidelines:
    • We should create Erlang Packaging Guidelines which doesn't exist yet.

Upgrade/compatibility impact

Every Erlang upgrade requires the rebuilding of modules which contains ports or NIFs, and we will rebuild all such modules in Fedora. However if a user has some additional modules not available in a Fedora repository,then (s)he has to rebuild it manually.

How To Test

  • Ensure that high-grade Erlang applications are still working:
Name Tested
couchdb Yes
ejabberd No
mochiweb No
rabbitmq-server Yes
riak No (broken currently)
wings Yes
  • Collect feedback from volunteers regarding their experience with this Erlang/OTP version

User Experience

Fedora Erlang users will get more robust Erlang configurations. Less issues, more detailed logs.


The following packages must be rebuilt:

Name Rebuilt
couchdb Yes
ejabberd Yes
erlang-basho_metrics Yes
erlang-bitcask Yes
erlang-cl Yes
erlang-ebloom Yes
erlang-eleveldb Yes
erlang-emmap Yes
erlang-erlsyslog Yes
erlang-esasl Yes
erlang-esdl Yes
erlang-js Yes
erlang-sd_notify Yes
erlang-skerl Yes
erlang-snappy Yes
wings Yes

Contingency Plan

  • Contingency mechanism: None necessary. Instead of falling back to the previous version we should fix existing packages in order to help the Community. We should also monitor upstream development process for potentially discovered issues and proactively apply patches (as we already did with Erlang R14, Erlang R15, and Erlang R16). It should be noted that this change consists from an independent or loosely coupled smaller changes. If we fail to deliver some changes in time, we should reschedule these exact changes to the future Fedora release while keeping already implemented ones.
  • Contingency deadline: N/A
  • Blocks release? N/A
  • Blocks product? N/A


N/A (not a System Wide Change)

Release Notes

Erlang/OTP R17 with partial Ellyptic Curve Cryptography support is available in Fedora 21. This release also has better systemd integration, and more modularized structure.