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Erlang 18


Update Erlang/OTP to version 18, and improve Erlang support in Fedora.


Current status

Detailed Description

Upgrade Erlang to version 18 which brings a lot of good stuff. Just a few highlights:

  • A lot of scalability and performance improvements.
  • Even better Ellyptic Curve Crypto support.
  • Initial support for IPv6 Erlang clustering. See these GitHub pull requests - #602 and #864.
  • New language feature - maps.
  • Better, production-ready HiPE support.

Aside from this, we plan to improve quality of Erlang and related packages. These are shortcomings we want to address:

  • We should enable so-called dirty NIF scheduler which is disabled currently.
  • Every daemon written in Erlang has its own logging solution which doesn't use neither syslog nor Journald. We should start switching them to Journald.
  • Erlang packaging is quite complex and mostly undocumented.
  • Improve coredump producing (see this patch for further details) and investigating.

Benefit to Fedora

Fedora users, both developers and end-users, will have visible benefits from using Fedora-provided packages. Namely:

  • Even better EC support in Erlang. Enough to start experimenting with cryptocurrencies using Erlang out of the box.
  • More scalable and reliable applications with better performance.
  • Better support for running Erlang apps in a fully IPv6 environments.
  • Improved logging, better unified with the rest of system.
  • Improved post-mortem Erlang applications analysis.
  • Packagers won't be afraid of packaging Erlang-related applications anymore. Also they will spend less time on packaging.


  • Proposal owners:
    • Upgrade Erlang to the latest version (18.2.2). Done!
    • We must rebuild every package which requires NIF or Driver version (listed below in the Dependencies section) against Erlang 18.2.x. Done!
    • 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
    • Add another default directory to look for Erlang *.beam files.
    • Every Erlang package must require erlang-rebar (or erlang-rpm-macros directly). Done.
    • Upgrade outdated packages:
      • {Ejabberd Done!
        • We'd better to package all the bundled libraries Ejabberd requires. This bug has all of the needed review requests marked as blockers. Done!
      • Riak
        • Riak has growing Bugzilla backlog, and badly outdated. We have to address all of these issues and package some additional libraries required by new Riak version. Unfortunately it has been retired. We'll re-add it later.
      • Wings3D Done!
  • 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 these modules must be rebuilt manually.

How To Test

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

User Experience

Users will get more robust, scalable, and fast Erlang applications.


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-lfe 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, Erlang R16, and Erlang 17). 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


Release Notes

Erlang/OTP 18.3.4 is available in Fedora 24.