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= Better Erlang Integration =
= Better Erlang Support =


== Summary ==
== Summary ==
<!-- A sentence or two summarizing what this change is and what it will do. This information is used for the overall changeset summary page for each release. -->
Update Erlang/OTP to R17, and improve Erlang integration with the rest of Fedora.


== Owner ==
== Owner ==
* Name: [[User:Peter|Peter Lemenkov]], [[SIGs/Erlang|Fedora Erlang SIG]]
* Name: [[User:Peter|Peter Lemenkov]], [[User:Skottler|Sam Kottler]], [[SIGs/Erlang|Fedora Erlang SIG]]
* Email: lemenkov@gmail.com, erlang@lists.fedoraproject.org
* Email: lemenkov@gmail.com, skottler [at] redhat.com, erlang@lists.fedoraproject.org
* Release notes owner: <!--- To be assigned by docs team [[User:FASAccountName| Release notes owner name]] <email address> -->
* Release notes owner: <!--- To be assigned by docs team [[User:FASAccountName| Release notes owner name]] <email address> -->
<!--- UNCOMMENT only for Changes with assigned Shepherd (by FESCo)
<!--- UNCOMMENT only for Changes with assigned Shepherd (by FESCo)
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CLOSED as NEXTRELEASE -> change is completed and verified and will be delivered in next release under development
CLOSED as NEXTRELEASE -> change is completed and verified and will be delivered in next release under development
-->
-->
* Tracker bug: <will be assigned by the Wrangler>
* Tracker bug: [https://bugzilla.redhat.com/show_bug.cgi?id=1086146 #1086146]


== Detailed Description ==
== Detailed Description ==
<!-- Expand on the summary, if appropriate. A couple sentences suffices to explain the goal, but the more details you can provide the better. -->
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:
 
* [https://bugzilla.redhat.com/1023017 Enable fine grained EC crypto support] by upgrading Erlang to the latest R17 (not yet released, and scheduled to April, 2014).
* Start working on a better systemd support in Erlang by enabling EPMD systemd support. This could be done by merging [https://github.com/matwey/otp/tree/systemd patches from Matwey V. Kornilov] and [https://build.opensuse.org/package/show/openSUSE:Factory/erlang systemd unit-files from openSUSE].
* Add [https://github.com/travelping/ejournald erlang-ejournald], [https://github.com/travelping/lager_journald_backend erlang-lager_journald_backend], and make Journald as a default logging backend.
* [https://bugzilla.redhat.com/784693 Split-off infrequently used modules] which requires X11, Pulseaudio and ensure that it won't break anything.
* Fix the long-standing noarch issue by providing additional default location for Erlang bytecode data.
* Update Erlang RPM-related macros to improve packaging by reducing spec-file sizes.


== Benefit to Fedora ==
== Benefit to Fedora ==
<!-- What is the benefit to the platform?  If this is a major capability update, what has changed?  If this is a new functionality, what capabilities does it bring? Why will Fedora become a better distribution or project because of this proposal?-->
* 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.


== Scope ==
== Scope ==
<!-- What work do the developers have to accomplish to complete the change in time for release?  Is it a large change affecting many parts of the distribution or is it a very isolated change? What are those changes?-->
* Proposal owners:
* Proposal owners:
<!-- What work do the feature owners have to accomplish to complete the feature in time for release?  Is it a large change affecting many parts of the distribution or is it a very isolated change? What are those changes?-->
** We must rebuild Erlang R17 and submit it to build-overrides.
 
*** We have to rebuild all the packages listed below in the [[#Dependencies|Dependencies]] section.
* Other developers: N/A (not a System Wide Change) <!-- REQUIRED FOR SYSTEM WIDE CHANGES -->
** '''DONE''' <s>A necessary *.socket unit must be added to erlang-erts to enable EPMD socket activation</s>.
<!-- What work do other developers have to accomplish to complete the feature in time for release?  Is it a large change affecting many parts of the distribution or is it a very isolated change? What are those changes?-->
*** Every Erlang daemon's systemd unit must require epmd.socket.
 
*** Allow EPMD implementation switching - Erlang is about choice!
* Release engineering: N/A (not a System Wide Change)  <!-- REQUIRED FOR SYSTEM WIDE CHANGES -->
** We need to fill new review request for erlang-ejournald
<!-- Does this feature require coordination with release engineering (e.g. changes to installer image generation or update package delivery)?  Is a mass rebuid required?  If a rel-eng ticket exists, add a link here.  -->
*** 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.
* Policies and guidelines: N/A (not a System Wide Change) <!-- REQUIRED FOR SYSTEM WIDE CHANGES -->
** Add another default directory to look for Erlang *.beam files.
<!-- Do the packaging guidelines or other documents need to be updated for this feature?  If so, does it need to happen before or after the implementation is done?  If a FPC ticket exists, add a link here. -->
** 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 ==
== Upgrade/compatibility impact ==
<!-- What happens to systems that have had a previous versions of Fedora installed and are updated to the version containing this change? Will anything require manual configuration or data migration? Will any existing functionality be no longer supported? -->
Every Erlang upgrade requires the rebuilding of modules which contains [http://www.erlang.org/doc/reference_manual/ports.html ports] or [http://www.erlang.org/doc/tutorial/nif.html 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.
 
<!-- REQUIRED FOR SYSTEM WIDE CHANGES -->
N/A (not a System Wide Change)  


== How To Test ==
== How To Test ==
<!-- This does not need to be a full-fledged document. Describe the dimensions of tests that this change implementation is expected to pass when it is done.  If it needs to be tested with different hardware or software configurations, indicate them.  The more specific you can be, the better the community testing can be.


Remember that you are writing this how to for interested testers to use to check out your change implementation - documenting what you do for testing is OK, but it's much better to document what *I* can do to test your change.
* Ensure that high-grade Erlang applications are still working:
{| border="1"
|-
| '''Name''' || '''Tested'''
|-
| {{package|couchdb}}  || {{yes}}
|-
| {{package|ejabberd}} || {{no}}
|-
| {{package|mochiweb}} || {{no}}
|-
| {{package|rabbitmq-server}} || {{yes}}
|-
| {{package|riak}} || {{no}} (broken currently)
|-
| {{package|wings}} || {{yes}}
|}


A good "how to test" should answer these four questions:
* Collect feedback from volunteers regarding their experience with this Erlang/OTP version
 
0. What special hardware / data / etc. is needed (if any)?
1. How do I prepare my system to test this change? What packages
need to be installed, config files edited, etc.?
2. What specific actions do I perform to check that the change is
working like it's supposed to?
3. What are the expected results of those actions?
-->
 
<!-- REQUIRED FOR SYSTEM WIDE CHANGES -->
N/A (not a System Wide Change)


== User Experience ==
== User Experience ==
<!-- If this change proposal is noticeable by its target audience, how will their experiences change as a result?  Describe what they will see or notice. -->
Fedora Erlang users will get more robust Erlang configurations. Less issues, more detailed logs.
<!-- REQUIRED FOR SYSTEM WIDE CHANGES -->
N/A (not a System Wide Change)


== Dependencies ==
== Dependencies ==
<!-- What other packages (RPMs) depend on this package?  Are there changes outside the developers' control on which completion of this change depends?  In other words, completion of another change owned by someone else and might cause you to not be able to finish on time or that you would need to coordinate?  Other upstream projects like the kernel (if this is not a kernel change)? -->


<!-- REQUIRED FOR SYSTEM WIDE CHANGES -->
The following packages must be rebuilt:
N/A (not a System Wide Change)
 
{| border="1"
|-
| '''Name''' || '''Rebuilt'''
|-
| {{package|couchdb}}  || {{yes}}
|-
| {{package|ejabberd}}  || {{yes}}
|-
| {{package|erlang-basho_metrics}}  || {{yes}}
|-
| {{package|erlang-bitcask}}  || {{yes}}
|-
| {{package|erlang-cl}}  || {{yes}}
|-
| {{package|erlang-ebloom}}  || {{yes}}
|-
| {{package|erlang-eleveldb}}  || {{yes}}
|-
| {{package|erlang-emmap}}  || {{yes}}
|-
| {{package|erlang-erlsyslog}}  || {{yes}}
|-
| {{package|erlang-esasl}}  || {{yes}}
|-
| {{package|erlang-esdl}}  || {{yes}}
|-
| {{package|erlang-js}}  || {{yes}}
|-
| {{package|erlang-sd_notify}}  || {{yes}}
|-
| {{package|erlang-skerl}}  || {{yes}}
|-
| {{package|erlang-snappy}}  || {{yes}}
|-
| {{package|wings}}  || {{yes}}
|}


== Contingency Plan ==
== Contingency Plan ==
<!-- If you cannot complete your feature by the final development freeze, what is the backup plan?  This might be as simple as "Revert the shipped configuration". Or it might not (e.g. rebuilding a number of dependent packages). If you feature is not completed in time we want to assure others that other parts of Fedora will not be in jeopardy. -->
* 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 [[Features/Erlang_R14|Erlang R14]], [[Features/Erlang_R15|Erlang R15]], and [[Features/Erlang_R16|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 mechanism: (What to do?  Who will do it?) N/A (not a System Wide Change)  <!-- REQUIRED FOR SYSTEM WIDE CHANGES -->
* Contingency deadline: N/A
<!-- When is the last time the contingency mechanism can be put in place?  This will typically be the beta freeze. -->
* Blocks release? N/A
* Contingency deadline: N/A (not a System Wide Change)  <!-- REQUIRED FOR SYSTEM WIDE CHANGES -->
* Blocks product? N/A
<!-- Does finishing this feature block the release, or can we ship with the feature in incomplete state? -->
* Blocks release? N/A (not a System Wide Change), Yes/No <!-- REQUIRED FOR SYSTEM WIDE CHANGES -->
* Blocks product? product <-- Applicable for Changes that blocks specific product release/Fedora.next -->


== Documentation ==
== Documentation ==
Line 101: Line 155:


== Release Notes ==
== Release Notes ==
<!-- The Fedora Release Notes inform end-users about what is new in the release.  Examples of past release notes are here: http://docs.fedoraproject.org/release-notes/ -->
<!-- The release notes also help users know how to deal with platform changes such as ABIs/APIs, configuration or data file formats, or upgrade concerns.  If there are any such changes involved in this change, indicate them here.  A link to upstream documentation will often satisfy this need.  This information forms the basis of the release notes edited by the documentation team and shipped with the release.


Release Notes are not required for initial draft of the Change Proposal but has to be completed by the Change Freeze.  
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.
-->


[[Category:ChangePageIncomplete]]
<!-- [[Category:ChangePageIncomplete]] -->
[[Category:ChangeAcceptedF21]]
<!-- When your change proposal page is completed and ready for review and announcement -->
<!-- When your change proposal page is completed and ready for review and announcement -->
<!-- remove Category:ChangePageIncomplete and change it to Category:ChangeReadyForWrangler -->
<!-- remove Category:ChangePageIncomplete and change it to Category:ChangeReadyForWrangler -->

Latest revision as of 12:18, 18 November 2014

Better Erlang Support

Summary

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

Owner

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.

Scope

  • 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.

Dependencies

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

Documentation

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.

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