Per the spec [1]: contributor/ – anything related to contributing to the project or how the team is managed. Applies to some of the current content under /developer, we are changing the name to emphasize that not all contributors are developers and sometimes developers are users but not contributors. We currently have a handful of docs that focus on the "how to develop or contribute" aspects of nova, and these are moved. Docs that focus on architecture or design decisions for nova are not moved, as these will go into 'reference'. A TODO is added to the former 'api_plugins' document as it's mega out-of-date and needs some serious work. [1] specs.openstack.org/openstack/docs-specs/specs/pike/os-manuals-migration Change-Id: Iad770688b4eafeb9caa710b4398b02d80a017a70
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Development Quickstart
This page describes how to setup and use 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 build the documentation and run the nova unit tests. If you want to be able to run nova (i.e., launch VM instances), you will also need to --- either manually or by letting DevStack do it for you --- 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.
Note
For how to contribute to Nova, see HowToContribute. Nova uses the Gerrit code review system, GerritWorkflow.
Setup
There are two ways to create a development environment: using DevStack, or explicitly installing and cloning just what you need.
Using DevStack
See Devstack Documentation. If you would like to use Vagrant, there is a Vagrant for DevStack.
Explicit Install/Clone
DevStack installs a complete OpenStack environment. Alternatively, you can explicitly install and clone just what you need for Nova development.
Getting the code
Grab the code from git:
git clone https://git.openstack.org/openstack/nova
cd nova
Linux Systems
The first step of this process is to install the system (not Python) packages that are required. Following are instructions on how to do this on Linux and on the Mac.
Note
This section is tested for Nova on Ubuntu (14.04-64) 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 listed in the
bindep.txt
file.
On Debian-based distributions (e.g., Debian/Mint/Ubuntu):
sudo apt-get install python-pip
sudo pip install tox
tox -e bindep
sudo apt-get install <indicated missing package names>
On Fedora-based distributions (e.g., Fedora/RHEL/CentOS/Scientific Linux):
sudo yum install python-pip
sudo pip install tox
tox -e bindep
sudo yum install <indicated missing package names>
On openSUSE-based distributions (SLES 12, openSUSE Leap 42.1 or Tumbleweed):
sudo zypper in python-pip
sudo pip install tox
tox -e bindep
sudo zypper in <indicated missing package names>
Mac OS X Systems
Install virtualenv:
sudo easy_install virtualenv
Check the version of OpenSSL you have installed:
openssl version
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) or Mac OS X 10.10.3 (OpenSSL 0.9.8zc) works fine with nova. OpenSSL versions from brew like OpenSSL 1.0.1k work fine as well.
Building the Documentation
Install the prerequisite packages: graphviz
To do a full documentation build, issue the following command while the nova directory is current.
tox -edocs
That will create a Python virtual environment, install the needed Python prerequisites in that environment, and build all the documentation in that environment.
Running unit tests
See Running Python Unit Tests.
Note that some unit and functional tests use a database. See the file
tools/test-setup.sh
on how the databases are set up in the
OpenStack CI environment and replicate it in your test environment.
Using a remote debugger
Some modern IDE such as pycharm (commercial) or Eclipse (open source) support remote debugging. In order to run nova with remote debugging, start the nova process with the following parameters --remote_debug-host <host IP where the debugger is running> --remote_debug-port <port it is listening on>
Before you start your nova process, start the remote debugger using the instructions for that debugger. For pycharm - http://blog.jetbrains.com/pycharm/2010/12/python-remote-debug-with-pycharm/ For Eclipse - http://pydev.org/manual_adv_remote_debugger.html
More detailed instructions are located here - http://novaremotedebug.blogspot.com
Using fake computes for tests
The number of instances supported by fake computes is not limited by physical constraints. It allows you to perform stress tests on a deployment with few resources (typically a laptop). But you must avoid using scheduler filters limiting the number of instances per compute (like RamFilter, DiskFilter, AggregateCoreFilter), otherwise they will limit the number of instances per compute.
Fake computes can also be used in multi hypervisor-type deployments in order to take advantage of fake and "real" computes during tests:
- create many fake instances for stress tests
- create some "real" instances for functional tests
Fake computes can be used for testing Nova itself but also applications on top of it.