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From Adrian Cole <>
Subject [PROPOSAL] Zipkin for Apache Incubator
Date Fri, 17 Aug 2018 09:29:47 GMT
I would like to propose Zipkin as an Apache Incubator project.

The text of the proposal can be found below as well as on the Incubator wiki:

I believe we should have 3 mentors.. currently we have 2 (plus Wu
Sheng and I who are familiar but not mentor-grade :P). If another
person can volunteer to mentor us, would be sweet.


= Abstract =
Zipkin is a distributed tracing system. It helps gather timing data
needed to troubleshoot latency problems in microservice architectures.
It manages both the collection and lookup of this data. Zipkin’s
design is based on the Google Dapper paper.

= Proposal =
Zipkin provides a defined data model and payload type for distributed
trace data collection. It also provides an UI and http api for
querying the data. Its server implements this api and includes
abstractions for storage and transport of trace payloads. The
combination of these parts avoid lock-in to a specific tracing
backend. For example, Zipkin includes integration with different open
source storage mechanisms like Apache Cassandra and Elasticsearch. It
also includes bridges to convert collected data and forward it to
service offerings such as Amazon X-Ray and Google Stackdriver.
Ecosystem offering extend this portability further.

While primarily focused on the system, Zipkin also includes tracing
libraries which applications use to report timing information.
Zipkin's core organization includes tracer libraries written in Java,
Javascript, Go, PHP and Ruby. These libraries use the formats
mentioned above to report data, as well "B3" which is a header format
needed to send trace identifiers along with production requests. Many
Zipkin libraries can also send data directly to other services such as
Amazon X-Ray and Google Stackdriver, skipping any Zipkin
infrastructure. There are also more Zipkin tracing libraries outside
the core organization than inside it. This is due to the "OpenZipkin"
culture of promoting ecosystem work.

= Background =
Zipkin began in 2012 at Twitter during a time they were investigating
performance problems underlying the "fail whale" seen by users. The
name Zipkin is from the Turkish word for harpoon: the harpoon that
will kill the failures! Incidentally, Zipkin was not the first tracing
system, it had roots in a former system at Twitter named
BigBrotherBird. It is due to BigBrotherBird that the de-facto tracing
headers we still use today include the prefix "X-B3".

In 2015, a community of users noticed the project was not healthy in
so far as it hadn't progressed and often didn't accept pull requests,
and the Cassandra backend was stuck on an unmaintained library. For
example, the Apache Incubator H-Trace project started in some ways as
a reaction to the inability to customize the code. The root cause of
this was Twitter moving to internal storage (Manhattan) and also the
project not being managed as a product. By mid 2015, the community
regrouped as OpenZipkin and the codebase moved from Twitter to an org
also named OpenZipkin. This led to fast progress on concerns including
initially a server rewrite and Docker based deployment.

In 2018, the second version of the data model completed, and along the
way, many new libraries became standard, including javascript, golang
and PHP. The community is dramatically larger than 2015, and Zipkin
remains the most popular tracing system despite heavy competition.

= Rationale =
Zipkin is a de-facto distributed tracing system, which is more
important as architectures become more fine grained due to popularity
of microservice or even serverless architectures. Applications
transition to use more complex communication including asynchronous
code and service mesh, increasing the need for tools that visualize
the behavior of requests as they map across an architecture.

Zipkin's server is focused only on distributed tracing. It is meant to
be used alongside existing logging and metrics systems. Generally, the
community optimizes brown field concerns such as interop over breaking
changes such as experimental features. The combination of code and
community make Zipkin a safe and easier choice for various sites to
introduce or grow their observability practice.

= Initial Goals =
The initial goals are to mature OpenZipkin's community process. For
example, while OpenZipkin has a good collaborative process, it lacks
formality around project management functions defined in the Apache
Software Foundation (ASF). We also seek out help with brand abuse
which is becoming common practice in the competitive landscape, yet
demotivates volunteers. Towards volunteers, help with on boarding
summer of code and funding for those who cannot afford to get to
conferences on their own would be nice. Finally, we occasionally have
organizations who are constrained to only work with foundation
projects: ASF is often mentioned, and being in the ASF removes this
collaboration roadblock.

Zipkin will not move all existing code into Apache. In fact, most
Zipkin ecosystem exists outside our org! The goal is to start with the
data formats and server code. Possibly the java client-side libraries
can move initially as well, depending on community feedback.

= Current Status =
== Meritocracy ==
Zipkin is an active community of contributors who are encouraged to
become committers. A Zipkin committer understands the importance of
seeking community feedback, and the gravity of brown field concerns.
Committers express diverse interest by contributing beyond their sites
immediate needs and acknowledging features require diverse need before
being merged into the core repositories. A camaraderie between
committers and not yet committers exists and is re-inforced with face
to face meetups where possible. We expect this to continue and build
with incubation and ideally acceptance into the Apache Software
Foundation (ASF).

Zipkin encourages involvement from its community members, and the
issues are open and available to any developers who wish to contribute
to the project. The Zipkin team currently seeks help and asks for
suggestions utilizing zipkin-user and zipkin-dev Google groups and
Gitter chat on While all
contributions are reviewed, generally a "rule of three" policy on
diverse need must be met before a feature is considered standard.

== Community ==
Zipkin has a highly active and growing community of users and
developers. The community is currently fostered on chat and issues in their respective
GitHub repositories, notably the main server:

There are well over 1000 users in the chat room and hundreds who
contributed code to code in the main OpenZipkin GitHub org. Interest
metrics have grown dramatically: For example, in three years and a
month from when Zipkin began until the time OpenZipkin formed, its
main repository accumulated 2400 GitHub stars. In the same time after,
it accumulated over 6700. Other metrics such as blog count and
community meetings have similarly gone way up. We expect further
growth as more learn about Zipkin and can engage with Zipkin through
the guidance of the Apache Software Foundation (ASF).

== Core Developers ==
The core contributors are a diverse group comprised of both
unaffiliated developers and those hailing from small to large
companies. They are scattered geographically, and some are highly
experienced industry as well as open source developers. Though their
backgrounds may be diverse, the contributors are united in their
belief in community driven software development.

More detailed information on the core developers and contributors in
general can be found under the section on homogeneous developers.

== Alignment ==
Zipkin adoption is growing, and it is no longer feasible for it to
remain as an isolated project. Apache is experienced in dealing with
software that is very widely accepted and has a growing audience. The
proposers believe that the Zipkin team can benefit from the ASF's
experience and its broad array of users and developers.

Zipkin supports several Apache projects and options exist for
integration with others. Apache CXF, Apache Camel, Apache Incubator
SkyWalking and Apache Incubator HTrace all utilize Zipkin APIs in
their core repositories. Many more do via community extensions. Apache
Maven is primarily use by Zipkin, and can be used by projects who
build upon Zipkin projects.

== Known Risks ==
=== Orphaned products ===
Zipkin is already being utilized at multiple companies that are
actively participating in improving the code. The thriving community
centered around Zipkin has seen steady growth, and the project is
gaining traction with developers. The risks of the code being
abandoned are minimal.

=== Inexperience with Open Source ===
Zipkin rebooted its community in July 2015 and grown there for over
three years. Additionally, many of the committers have extensive
experience with other open source projects. Zipkin fosters a
collaborative and community-driven environment.

In the interest of openly sharing technology and attracting more
community members, several of our developers also regularly attend
conferences in North America and Europe to give talks about Zipkin.
Zipkin meetups are also planned every few months for developers and
community members to come together in person and discuss ideas.

=== Homogenous Developers ===
At the time of the writing, OpenZipkin's core 12 developers all work
at different companies around the globe. Most operate their own
tracing sites, but some no longer operate sites at all: staying for
the community we've built. Our ASF champion, Mick Semb Wever, is both
a committer and an experienced ASF member.

The Zipkin developers thrive upon the diversity of the community. The
Zipkin gitter channel is always active, and the developers often
collaborate on fixes and changes in the code. They are always happy to
answer users' questions as well.

Zipkin is interested in continuing to expand and strengthen its
network of developers and community members through the ASF.

=== Reliance on Salaried Developers ===
Zipkin has one full time salaried developer, Adrian Cole. Though some
of the developers are paid by their employer to contribute to Zipkin,
many Zipkin developers contribute code and documentation on their own
time and have done so for a lengthy period. Given the current stream
of development requests and the committers' sense of ownership of the
Zipkin code, this arrangement is expected to continue with Zipkin'
induction into the ASF.

=== Relationships with Other Apache Products ===
Zipkin, Apache Incubator Skywalking and Apache Incubator HTrace
address similiar use cases. Most similarities are between Zipkin and
HTrace: Zipkin hopes to help serve the community formerly served by
HTrace, but understands the data services focus of HTrace may require
different tooling. SkyWalking addresses more feature surface than
Zipkin. For example, metrics collection is not a goal of Zipkin, yet
it is a goal of SkyWalking. SkyWalking accepts Zipkin formats and can
be used as a replacement server. SkyWalking PPMC member, Sheng Wu, has
been a routine member of Zipkin design discussions and has offered to
help Zipkin through ASF process.

While Zipkin does not directly rely upon any Apache project, zipkin
supports several Apache projects. Apache CXF, Apache Camel, Apache
Incubator SkyWalking, Apache Incubator Dubbo, Apache Incubator
ServiceComb and Apache Incubator HTrace all utilize Zipkin APIs in
their core repositories. Many more do via community extensions. Apache
Maven is primarily use by Zipkin, and can be used by projects who
build upon Zipkin projects.

=== A Excessive Fascination with the Apache Brand ===
Zipkin recognizes the fortitude of the Apache brand, but the
motivation for becoming an Apache project is to strengthen and expand
the Zipkin community and its user base. While the Zipkin community has
seen steady growth over the past several years, association with the
ASF is expected to expedite this pattern of growth. Development is
expected to continue on Zipkin under the Apache license whether or not
it is supported by the ASF.

== Documentation ==
The Zipkin project documentation is publicly available at the following sites:

  * project overview
  * swagger specification
  * header formats
  * Javadocs for the Zipkin server

== Initial Source ==
The initial source is located on GitHub in the following repositories:

  * git://
  * git://
  * git://
  * git://
  * git://
  * git://
  * git://
  * git://
  * git://
  * git://
  * git://
  * git://
  * git://
  * git://
  * git://
  * git://
  * git://

Depending on community progress, other repositories may be moved as well

== Source and Intellectual Property Submission Plan ==
Zipkin's initial source is licensed under the Apache License, Version

All source code is copyrighted to 'The OpenZipkin Authors', to which
the existing core community(members list in Initial Committers) has
the rights to re-assign to the ASF.

== External Dependencies ==
This is a listing of Maven coordinates for all of the external
dependencies Zipkin uses. All of the dependencies are in Sonatype and
their licenses should be accessible.

== Cryptography ==
Zipkin contains no cryptographic algorithms.

= Required Resources =
== Mailing Lists ==
  * Zipkin-dev: for development discussions
  * Zipkin-user: for community discussions
  * Zipkin-private: for PPMC discussions
  * Zipkin-commits: for code changes

== Git Repositories ==
The Zipkin team is experienced in git and requests to transfer GitHub
repositories(list in Initial Source) to Apache.

== Issue Tracking ==
The community would like to continue using GitHub Issues.

= Initial Committers =
  * Zoltán Nagy
  * Adrian Cole, Pivotal
  * Bas van Beek
  * Brian Devins
  * Eirik Sletteberg
  * Jeanneret Pierre-Hugues
  * Jordi Polo Carres
  * José Carlos Chávez
  * Kristof Adriaenssens
  * Lance Linder
  * Mick Semb Wever,
  * Tommy Ludwig

= Champion =
 * Michael Semb Wever,

= Mentors =
 * Michael Semb Wever,
 * Andriy Redko,

= Sponsoring Entity =
We are requesting the Apache Incubator to sponsor this project.

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