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From Apache Wiki <>
Subject [Incubator Wiki] Update of "DeltacloudProposal" by DavidLutterkort
Date Thu, 06 May 2010 19:35:56 GMT
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The "DeltacloudProposal" page has been changed by DavidLutterkort.


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= Deltacloud, a cross-cloud web service API =

== Abstract ==

Deltacloud defines a web service API for interacting with cloud service
providers and resources in those clouds in a unified manner. In addition,
it consists of a number of implementations of this API for the most popular

== Proposal ==

  * Define a REST-based API for managing and manipulating cloud resources in a manner that
isolates the API client as much as possible from the particulars of specific cloud API's
  * Provide an open API definition for cloud providers for their IaaS clouds and a basis on
which PaaS providers can layer their offering
  * Provide image management and directory capabilities as part of the API
  * The current implementation allows instance lifecycle management (create, start, stop,
destroy, reboot), and querying of related resources like available images, instance sizes,
and allowed instance actions for a number of public and private clouds
  * Currently supported are Amazon EC2, Eucalyptus, Rackspace, RimuHosting, GoGrid, OpenNebula,
and RHEV-M
  * Future enhancements should broaden the scope of the API to include networking, firewalling,
authentication, accounting, and image management

== Background ==

An important issue for cloud users is that of avoiding lock-in to a
specific cloud. By providing a cross-cloud API for
infrastructure-as-a-service (IaaS) clouds, Deltacloud addresses this
concern and strives to provide the best possible API for writing
cloud-management applications that can target multiple clouds.

There are also no efforts currently to define a truly open-source cloud
API, one for which there is a proper upstream, independent of any specific
cloud provider. Deltacloud API strives to create a community around
building an open-source cloud API in a manner that fully allows for
tried-and-true open source mechanisms such as user-driven innovation.

By providing a web-service API, Deltacloud is language agnostic, and one of
its subordinated goals is to provide a practical vocabulary for talking
about IaaS cloud resources and operations on them.

== Rationale ==

IaaS clouds provide numerous advantages to their users, for example,
making provisioning new servers more agile. If users directly use the
'native' cloud API's, they risk locking themselves in to the API of a
specific cloud provider.

There is therefore a strong need for an API that can be used across a wide
range of public and private clouds, and that can serve as the basis for
developing cloud management applications; in contrast to several existing
language-specific efforts in this direction, Deltacloud is conceived as a
web service.

This will allow the project to attract a broad community of users of the
API and cloud providers interested in offering a truly open-source API,
with a proper upstream community.

We strongly believe that the best way to drive such an API effort is by
developing the API and open-source implementations of the API side-by-side.

== Initial Goals ==

Deltacloud is an existing open source project; initially started by Red
Hat, it has attracted a number of outside contributors. We look at moving
this project to the ASF as the next step to broaden the community, and put
the project on solid footing since the ASF governance model is well suited
for the Deltacloud project goals. The ASF is a great location for
Deltacloud to build a community and will benefit from ASL licensing.

== Current Status ==

Deltacloud API is licensed under the LGPL:

  * Deltacloud Website ( There are two projects hosted there: the API
under consideration here and the Aggregator (not part of this proposal, though also open source)
  * Deltacloud git repository (;a=summary)
  * Deltacloud mailing lists
    - users (
    - developers (

== Transition to Apache ==

All current contributors have consented to relicensing the Deltacloud API
code under the Apache Software License 2.0; the code will be relicensed to
ASL 2.0 on acceptance into the Incubator.

== Meritocracy ==

Deltacloud API accepts patches from anybody, based solely on technical
merit, and will give commit rights to contributors with a proven technical
track record. Communication is done through an IRC channel on freenode and
the two mailing lists above. The mailing lists will be migrated to the ASF
project list on acceptance into the Incubator.

== Community ==

Because it was started by Red Hat, the majority of the initial contribution
is from Red Hat employees, though we have received and accepted a number of
patches from outside sources, particularly, from a number of cloud
providers. We expect that the project will greatly increase in contribution
base, and this is one aspect the project will monitor in becoming ready for

== API Developers ==

  * Bob McWhirter (initial developer)
  * David Lutterkort (current maintainer)
  * Michal Fojtik
  * Ivan Meredith
  * Daniel Molina Aranda

== Alignment ==

Currently, there are no other Apache projects concerned with building a
cross-cloud API as a web service.  However, we feel it will be a strong
complement to the set of Apache projects, and provide any other Apache
project an API for interacting with any cloud provider.

== Known Risks ==

==== Orphaned Products ====

Deltacloud API is actively used by other Red Hat projects. I have
received interest in Deltacloud API both from some cloud providers and
other organizations in joining the project. We feel that it is
importatant to put formal governance in place both for the project and
the contributors as the project expands. We feel the ASF is the best
location for this.

==== Inexperience with Open Source ====

I have been involved with Open Source Software for over a decade; I
have actively contributed to puppet (, where
I was one of the earliest contributors, libvirt (,
virt-manager (, and a number of
other projects. I started and maintain two projects, Augeas
( and netcf (
related to systems management.

==== Homogenous Developers ====

While much of the initial code base has been written by Red Hat,
several of the backend drivers and some important aspects of the API
design have been heavily influenced by outside contributors.

==== Reliance on Salaried Developers ====

Currently the project has mostly salaried developers. Expanding the
diversity of the project's developers is one of the areas we will
actively work on in the Incubator, and will be a crucial factor in
making Deltacloud a successful project.

==== Relationships with Other Apache Products ====

Currently there are not really any stong relationships with other
Apache projects. There is a certain amount of overlap with libcloud
(, though the projects differ in
scope and goals. At its most basic, libcloud is a Python in-process
API, whereas Deltacloud is a web service written in Ruby.

==== An Excessive Fascination with the Apache Brand ====

We seek to build a lasting community around Deltacloud API; the most
important reason for proposing this project for the incubator is to
clarify project governance to other parties, to allow them more easily
to join and contribute to the project, and for the project to be
managed and governed independently.

== Documentation ==

  * API definition (
  * Supported drivers (
  * Ruby Client (
  * Writing new drivers (

Documentation is maintained in a separate, public git repository

== Initial Source ==

All sources can be found in the git repositories mentioned above.

== External Dependencies ==

Deltacloud is written in Ruby; there are a number of Ruby libraries that
the code depends on, most importantly:

  * Ruby
  * Sinatra (
  * HAML (
  * thin (

A complete list of dependencies can be found in the deltacloud-core.gemspec
in the core repository. All dependencies are licensed under either the Ruby
License or the MIT License.

== Cryptography ==

Uses standard Ruby APIs for SSL/HTTPS

== Required Resources ==

  * Mailing lists

    * deltacloud-devel
    * deltacloud-commits
    * deltacloud-private

  * Subversion


  * Issue Tracking

    * Bugzilla (deltacloud)

== Initial Committers ==

  * David Lutterkort <>
  * Michal Fojtik <>
  * Andrew N Cadel <>

== Sponsors ==

==== Champion ====
Carl Trieloff   <>

==== Nominated Mentors ====
  * Carl Trieloff   <>
  * Craig L Russell <>

==== Sponsoring Entity ====
Incubator PMC

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