Writing your First OpenStack Application¶
Currently, OpenStack is missing documentation similar to other Python projects, that introduces a new user to the API. One well known “first app” tutorial in the Python community is the Django web framework’s tutorial.
A guide has been written by members of the Application Ecosystem WG that introduces the OpenStack API, using a non-trivial Python application that serves as a teaching tool - similar to the poll app in the equivalent Django tutorial.
This book has been written for software developers who wish to deploy applications to OpenStack clouds.
We’ve assumed that the audience is an experienced programmer, but that they haven’t necessarily created an application for cloud in general, or for OpenStack in particular.
In addition to learning to deploy applications on OpenStack, the reader will also learn some best practices for cloud application development.
This tutorial actually involves two applications; the first, a fractal generator, simply uses mathematical equations to generate images. However, really, it’s just an excuse; the real application is the code that enables the reader to make use of OpenStack to run it. That application (and therefore this guide) includes:
- Creating and destroying compute resources.
- Cloud-related architecture decisions, such as microservices and modularity
- Scaling up and down to customize the amount of available resources.
- Object and block storage for persistance of files and databases.
- Orchestration services to automatically adjust to the environment.
- Networking customization for better performance and segregation.
- A few other crazy things we think ordinary folks won’t want to do ;).
The guide has been written with a strong preference for the most common API calls, so it will work across a broad spectrum of OpenStack versions. In addition, the authors have paid special attention that the first 3 sections should work almost regardless of OpenStack cloud configuration (basically Nova, Keystone and Glance are the only requirements, but neutron will be used if installed).
This content should be published to developer.openstack.org.
The content created during the sprint should be separated from the app.
The content created during the sprint documents how to use the OpenStack API and several OpenStack SDKs and the app is only an example use case. In theory the used app (Faafo at the moment) can be replaced in the future (or maybe we want to add a second use case) by an other app. Additionally, the focus of the documentation placed inside the repository of the app is different from the focus of the content created during the sprint. The documentation inside the repository of the app describes how to use the app itself (how to create a development environment, example outputs, ..), not how to use OpenStack SDKs and the OpenStack API.
As such, content will live in
openstack/api-site repository like
other documents published to http://developer.openstack.org. Therefore
the review team will be the standard docs reviewers for this
The guide has been written so that support for multiple SDKs is a core part of its publication. Initial sections have been written for libcloud, and section1 is also available for fog. The design philosophy is that the same prose can be used, with code samples swapped.
- Write content during the sprint
- Add standard build jobs
- Standard content review
- Prominently link the content on developer.openstack.org
The guide is written in such a way that all examples can be run by the reader, and steps have been taken to verify that all content is valid.
To date, libcloud sections 1-3 have been tested by at least 7 people on 7 different clouds that the authors are aware of, and the remaining sections with samples have been tested on at least 3 different clouds.
Fog in section1 has only had testing on one cloud, and should not be published until both section 1-3 is completed as a minmum and additional testing has been performed.
The testing process for this guide is similar to the install guide. A tester should take the role of a ‘naive’ reader, following the guide’s instructions exactly with no deviation. Any instructions that did not work, or are too difficult to follow should be noted as bugs and fixed.