This page describes how to setup a working Python development environment that can be used in developing nova on Ubuntu, Fedora or Mac OS X. These instructions assume you’re already familiar with git.
Following these instructions will allow you to run the nova unit tests. If you want to be able to run nova (i.e., launch VM instances), you will also need to install libvirt and at least one of the supported hypervisors. Running nova is currently only supported on Linux, although you can run the unit tests on Mac OS X.
Nova development uses a set of shell scripts in DevStack. Virtual enviroments with venv are also available with the source code.
The easiest way to build a fully functional development environment is with DevStack. Create a machine (such as a VM or Vagrant box) running a distribution supported by DevStack and install DevStack there. For example, there is a Vagrant script for DevStack at https://github.com/jogo/DevstackUp.
If you prefer not to use devstack, you can still check out source code on your local machine and develop from there.
This section is tested for Nova on Ubuntu (10.10-64) and Fedora-based (RHEL 6.1) distributions. Feel free to add notes and change according to your experiences or operating system.
Install the prerequisite packages.
sudo apt-get install python-dev libssl-dev python-pip git-core libxml2-dev libxslt-dev
On Ubuntu Precise (12.04) you may also need to add the following packages:
sudo apt-get build-dep python-mysqldb
On Fedora-based distributions (e.g., Fedora/RHEL/CentOS/Scientific Linux):
sudo yum install python-devel openssl-devel python-pip git gcc libxslt-devel mysql-devel
sudo easy_install virtualenv
Check the version of OpenSSL you have installed:
If you have installed OpenSSL 1.0.0a, which can happen when installing a MacPorts package for OpenSSL, you will see an error when running nova.tests.auth_unittest.AuthTestCase.test_209_can_generate_x509.
The stock version of OpenSSL that ships with Mac OS X 10.6 (OpenSSL 0.9.8l) or Mac OS X 10.7 (OpenSSL 0.9.8r) works fine with nova.
Grab the code from GitHub:
git clone https://github.com/openstack/nova.git cd nova
The unit tests will run by default inside a virtualenv in the .venv directory. Run the unit tests by doing:
The first time you run them, you will be asked if you want to create a virtual environment (hit “y”):
No virtual environment found...create one? (Y/n)
See Unit Tests for more details.
You can manually install the virtual environment instead of having run_tests.sh do it for you:
This will install all of the Python packages listed in the requirements.txt file into your virtualenv. There will also be some additional packages (pip, distribute, greenlet) that are installed by the tools/install_venv.py file into the virutalenv.
If all goes well, you should get a message something like this:
Nova development environment setup is complete.
To activate the Nova virtualenv for the extent of your current shell session you can run:
$ source .venv/bin/activate
Or, if you prefer, you can run commands in the virtualenv on a case by case basis by running:
$ tools/with_venv.sh <your command>