From Fedora Project Wiki

Erlang 20


Update Erlang/OTP to version 20.


Current status

Detailed Description

Upgrade Erlang to version 20 which brings a lot of good stuff. Just a few highlights:

  • So-called dirty schedulers are available on systems with SMP.
  • Atoms may now contain arbitrary Unicode characters (for example, 'здравствуй-你好').
  • Erlang application can handle some OS signals (SIGHUP, for example).
  • Improved unicode support for strings
  • The zlib module has been refactored and all its operations will now yield appropriately, allowing them to be used freely in concurrent applications.

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

  • 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.
  • We should add ability to use D-Bus via erlang-dbus library.
  • Further improve Erlang Packaging Guidelines.
  • Start building noarch Erlang packages we've implemented previously.

Benefit to Fedora

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

  • Even faster and smoother scheduling in Erlang. User's NIFs will work with less latency and smaller jitter.
  • Improved logging, better unified with the rest of system.


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.
  • Due to new atom's internal representation, some applications won't be able to deserialize data back serialized using previous Erlang version. The same applies to clustered applications - better upgrade and restart them entirely rather than adding a new upgraded nodes into a cluster.

How To Test

  • Ensure that high-grade Erlang applications are still working:
Name Tested
Package-x-generic-16.pngcouchdb No
Package-x-generic-16.pngejabberd No
Package-x-generic-16.pngelixir No
Package-x-generic-16.pngmochiweb No
Package-x-generic-16.pngrabbitmq-server No
Package-x-generic-16.pngriak No (package was retired :( )
Package-x-generic-16.pngwings No
  • 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
Package-x-generic-16.pngcouchdb No
Package-x-generic-16.pngerlang-basho_metrics Yes
Package-x-generic-16.pngerlang-bitcask No
Package-x-generic-16.pngerlang-cache_tab No
Package-x-generic-16.pngerlang-cl No
Package-x-generic-16.pngerlang-ebloom Yes
Package-x-generic-16.pngerlang-eleveldb No
Package-x-generic-16.pngerlang-emmap Yes
Package-x-generic-16.pngerlang-esip No
Package-x-generic-16.pngerlang-fast_tls No
Package-x-generic-16.pngerlang-fast_xml No
Package-x-generic-16.pngerlang-fast_yaml No
Package-x-generic-16.pngerlang-hyper No
Package-x-generic-16.pngerlang-iconv No
Package-x-generic-16.pngerlang-jiffy Yes
Package-x-generic-16.pngerlang-riak_ensemble No
Package-x-generic-16.pngerlang-sd_notify Yes
Package-x-generic-16.pngerlang-skerl Yes
Package-x-generic-16.pngerlang-snappy Yes
Package-x-generic-16.pngerlang-stringprep No
Package-x-generic-16.pngerlang-xmpp No

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, Erlang 17), Erlang 18, and Erlang 19. 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 20.2.3 is available in Fedora 28.