Creating an interoperable future for clouds - The 3rd CloudWATCH Cloud Plugfest and Standards Profile Workshop - Summary Report

A handful of coders converged at the 3rd CloudWATCH Cloud Plugfest and Standards profile Workshop, hosted at the EGI Big Data Solutions Workshop in Amsterdam on 25 September 2014. The principal work was to test Open Cloud Computing Interface (OCCI) and Cloud Data Management Interface (CDMI) standards against the ETSI test suite specifications.

Participants represented countries and institutions across the globe, from Czech Republic (CESNET), Brazil (EUBrazilCC), Spain (IFCA), Greece (GRNET) and the US. The developers spent the day testing and probing each others implementations to identify errors, implementation issues, while profiling the specific standards for quality control feedback to both OCCI and CDMI as well as ESTI themselves.

Even though implementations have been around for a while, regular testing is necessary as bugs are still in the software that have not been fixed, or regression bugs were introduced in the mean time. To facilitate regular interoperability testing, plugfests need to be lightweight and lean and should occur more often. Virtual plugfests are the way forward, using collaborative document platforms such as Google drive. Virtual plugfests also allow for greater flexibility. Indeed, it was agreed to extend this plugfest by a week.

Cloud plugfests have impact beyond the software, thus regular participation and inclusion of Standard Development Organisations (SDOs) is crucial for a number of reasons:

  1. Testing may reveal that software is faulty (the usual case)
  2. Testing may show that there are faults, contradictions and ambiguities in the specification(s) that need fixing.
  3. Testing may indicate  that the test cases and descriptions are faulty.

Disseminating existing material supplementing the bare standard specification document(s) is crucial for new implementations to ease uptake of standards. Comments from participants included "If I had known before I implemented CDMI...". Likewise, reference implementations and reference test suites should be endorsed by the respective stewarding SDO. Albeit, increasing the administrative burden on SDOs, maintained and managed reference implementations and (automated) test suites are key contributions to the success of a publicly defined standard. At the event, OGF agreed to evaluate changing its procedures to include reference implementations and reference (automated) test frameworks in its "standards delivery package".

Other concrete outcomes emerging from the event include:

  1. ETSI test set specification descriptions that need updating, changing should be identified and removed.
  2. Specification changes are required for OCCI in specifications (supported by earlier plugfests) such as HTTP response of "200 OK" and when to respond with a "201 CREATED" status.
  3. Assurance of site implementation according to specifications e.g.  the fogbow implementation of the EUBrazilCC project is generally implementing the OCCI standard, particularly the defined functionality.

However, strictly speaking, it is not interoperable since its OCCI message rendering is not entirely following the rules the set out in the OCCI specifications.
Leveraging these main outcomes, CloudWATCH will further address projects that participated at recent Software services and cloud computing concertation meetings. CloudWATCH will engage with those projects that use of publicly defined standards at the next Cloud plugfest meeting. The first steps have already been put into place by circulating the following questions to these projects:

  1. Which standards do you implement in your projects?
  2. Which standards do you require from the cloud services your project is based on?
  3. Did you perceive any difficulties in the interpretation of these standards?
  4. Are there any functionalities that are not yet covered by these standards but you do require in your project? Please list them.
  5. Were there any standards you considered implementing but refrained from doing so? Why?”

To aide with and raise awareness for the profile definition work, CloudWATCH will also produce a strawman Cloud Standards profile based on the OCCI standard, and an EGI Federated Cloud use case. This, however, will not be a full profile document, but it will provide a set of specific normative profiling statements including background context that would not normally appear in a profile document. The strawman then may be used as a blueprint to kick-off actual Standards profiling work.

CloudWATCH will continue organising Cloud plugfests in close cooperation with the partnership, while EGI will evaluate whether to run regular virtual plugfests internally (due to its own vested interest), and once established extend these to regular public virtual plugfests. The next CloudWATCH plugfest event is planned to be organised around Spring 2015.

To receive more information about Cloud plugfests, please contact us at

Authors: Sy Holsinger & Michel Drescher, & CloudWATCH