GSoC students create a Google Compute Engine interface to CloudStack

Wednesday, July 23, 2014

Today on the Open Source blog we have guest writer Sebastien Goasguen, an avid open source contributor and member of the Apache Software Foundation. Below, Sebastien highlights the significant contributions that two Google Summer of Code students have made to Apache CloudStack.

In December 2013, Google announced the General Availability (GA) of the public cloud, Google Compute Engine (GCE).  Apache CloudStack now has a brand new GCE compatible interface (Gstack) which allows users to take advantage of the GCE clients (i.e gcloud and gcutil) to access their CloudStack cloud. This interface was made possible through the Google Summer of Code (GSoC) program.

In the summer of 2013, Ian Duffy, a student from Dublin City University, participated in GSoC through the Apache Software Foundation and worked on a LDAP plugin to CloudStack. He did such a great job that he finished early and was made an Apache CloudStack committer. Since he finished his primary GSoC project so early, I encouraged him to take on another! He brought in a friend for the ride — Darren Brogan, another student at Dublin City University. Together they worked on the GCE interface to CloudStack and even learned Python in doing so.

Both Ian and Darren remained engaged with the CloudStack community and as their third year project in University, they successfully developed an Amazon EC2 interface to CloudStack. Since he enjoyed his experience so much, Darren also applied to the GSoC 2014 program and proposed to revisit Gstack, improve it, extend the unit tests, and make it compatible with the GCE v1 API. He is making excellent progress so far and we are all excited to see the results.

Technically, Gstack is a Python Flask application that provides a REST API compatible with the GCE API and forwards the requests to the corresponding CloudStack API. The source is available on GitHub and the binary is downloadable via PyPi.

Installation and Configuration of Gstack

Are you interested in using Gstack? Check out the full documentation. To get a taste for things, you can grab the binary package from Pypi using pip in one single command.

        pip install gstack

Or if you plan to explore the source and work on it, you can clone the repository and install it by hand. Pull requests are of course welcome.

       git clone
sudo python./ install

Both of these installation methods will install a gstack and a gstack-configure binary in your path. Before running Gstack you must configure it. To do so run:


And enter your configuration information when prompted. You will need to specify the host and port where you want gstack to run on, as well as the CloudStack endpoint that you want gstack to forward the requests to. In the example below we use the exoscale cloud:

   $ gstack-configure

   gstack bind address []: localhost

   gstack bind port [5000]:
Cloudstack host [localhost]:
Cloudstack port [8080]: 443
Cloudstack protocol [http]: https

   Cloudstack path [/client/api]: /compute

The information will be stored in a configuration file available at ~/.gstack/gstack.conf:

   $ cat ~/.gstack/gstack.conf 

   PATH = 'compute/v1/projects/'

   GSTACK_BIND_ADDRESS = 'localhost'
GSTACK_PORT = '5000'
   CLOUDSTACK_PATH = '/compute'

You are now ready to start Gstack in the foreground with:


That's all there is to running Gstack. You can then use gcutil to send requests to gstack which will forward them to a CloudStack endpoint.  Although it is still a work in progress, it is now compatible with GCE GA v1.0 API. It provides a solid base to start working on hybrid solutions between GCE public cloud and a CloudStack based private cloud.

GSoC has been a terrific opportunity for all of us at Apache. Darren and Ian both learned how to work with an open source community and ultimately became an integral part of it. They learned tools like JIRA, git, and Review Board and gained confidence working publicly on mailing lists. Their work on Gstack and EC2stack is certainly of high value to CloudStack and could eventually become the base for interesting products that will use hybrid clouds.

By Sebastien Goasguen, Senior Open Source Architect, Citrix and Apache Software Foundation member