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README.md

Getting Started

Source Code Management with Git

Familiarity with basic Git commands is needed for the success of this project. If you are new to Fork and Pull Requests, jump over to Fork and Pull Requests for a quick overview. Let's play with some of these commands.

First fork from https://github.com/OpenAcademy-OpenStack/playground into your own organization. The new repository can be cloned with the following command:

git clone git@github.com:<your-repository>/playground.git

Now try

cd playground
git remote -v

The output of the last command should look like this:

origin	git@github.com:<your-repository>/playground.git (fetch)
origin	git@github.com:<your-repository>/playground.git (push)

origin refers to the forked repository. Let's add the upstream repository as well:

git remote add upstream https://github.com/OpenAcademy-OpenStack/playground.git
git remote -v

There should be two remote repositories:

origin	git@github.com:<your-repository>/playground.git (fetch)
origin	git@github.com:<your-repository>/playground.git (push)
upstream	https://github.com/OpenAcademy-OpenStack/playground.git (fetch)
upstream	https://github.com/OpenAcademy-OpenStack/playground.git (push)

Next add a file or modify an existing one:

echo "Adding a new file" > myfile.txt

git status commmand should list "myfile.txt" as untracked. It can be added via this command:

git add myfile.txt

Next commit this change to the local repository with:

git commit -m "my first commit"

Let's add another line to "myfile.txt" and modify the first commit to include this change:

echo "\nThis is another line" >> myfile.txt
git add myfile.txt
git commit --amend

Modify the message as necessary and commit the change. Both changes can be pushed to the remote repository "origin" with this command:

git push origin master

In a browser go to the repository and verify that "myfile.txt" is there. While there you can go ahead and create a new pull request to get it merged to the upstream repository, that is the one in OpenAcademy-OpenStack organization.

Overtime your forked repository will get out of sync with the upstream. It is, therefore, important to sync it from time to time. Here's how:

git fetch upstream
git merge upstream/master
git push origin master

The first command brings in the latest from upstream repository. The second command merges all changes from the master branch in the upstream to the current local branch. And the last command pushes the new changes to the forked repository, thereby bringing it in sync with upstream.

There's much more to Git, but mastering those basic commands should suffice for now.

Python

Python is the language of choice for OpenStack. You're expected to code in Python for the project.

Python isn't hard to learn. However, it takes some time to write Pythonic code. For example, here's a piece of code that is translated from some other languages to Python:

languages = ["james", "john", "josh", "jay"]
found = False
for l in languages:
    if l.find("ay") >= 0:
        found = True
if found:
    print("Found a name that contains 'ay'")

Here's the *pythonic" version:

if [l for l in languages if "ay" in l]:
    print("Found a name that contains 'ay'")

If you marvel at the second version, you're in for a good ride. If not, it's just a matter of time. Here's a book that we've found useful, https://www.jeffknupp.com/writing-idiomatic-python-ebook-experiment. There are many other more out there.

We also recommend using Virtual Environments.

As for IDE, PyCharm is a good one, and there's a free community version. Regardless of which IDE you use, the expectation is that you follow the Style Guide for Python Code. It makes the code readable, and helps tremendously with code review.

Devstack

For this project you'll need access to a cloud environment. devstack is basically cloud-in-a-box. It deploys all OpenStack components and gives you your very own cloud deployment. You'll be testing your code against devstack.

Install Devstack with Vagrant

Install virtualbox

Install vagrant

Download vagrant box

vagrant box add base http://files.vagrantup.com/precise64.box

Use the following Vagrantfile to launch a vagrant VM

# -*- mode: ruby -*-
# vi: set ft=ruby :

Vagrant.configure("2") do |config|
  config.vm.box = "precise64"
  config.vm.network :private_network, ip: "192.168.50.4"
  config.vm.provider "virtualbox" do |vm|
    vm.customize ["modifyvm", :id, "--memory", 8192]
  end
end

Use vagrant ssh to login to VM.

Setup devstack using the following commands.

sudo apt-get update -y
sudo apt-get install git-core -y
git clone https://github.com/openstack-dev/devstack.git
cd devstack
git checkout stable/havana

Create a localrc file.

DATABASE_PASSWORD=password
RABBIT_PASSWORD=password
SERVICE_TOKEN=password
SERVICE_PASSWORD=password
ADMIN_PASSWORD=password

and run

./stack.sh

From your Mac, go to http://192.168.50.4. You should see OpenStack dashboard (called Horizon).

Manual Verification

First download the settings to use OpenStack command line interface (CLI) tools. Here is how.

  1. Login to the dashboard with username admin and password password.
  2. Click on the "Project" tab.
  3. Create a VM. Then click on the VM. Switch to the "Console" tab. You should be able to login to verify. Note that we're not going to focus on networking aspects in this project and hence do not expect to use the VMs for anything other than testing OpenStack functionality.
  4. Click on "Access and Security" link and then on the "API Access" tab. Click on "Download OpenStack RC File" to download a script with settings. Copy this file to your vagrant VM.
  5. Load these settings via source demo-openrc.sh. Enter password.

Add a new image.

  1. Download the file http://cloud-images.ubuntu.com/releases/12.04.2/release/ubuntu-12.04-server-cloudimg-amd64-disk1.img
  2. Upload the image via glance image-create --name ubuntu --disk-format=qcow2 --container-format=bare --is-public=True --file=./ubuntu-12.04-server-cloudimg-amd64-disk1.img
  3. Run glance index and note the UUID of the image you uploaded.
  4. Create a VM via nova boot --image {image UUID} --flavor m1.small myubuntu
  5. Wait for a minute or so and then run nova list to see the new VM listed.

Then run the following commands in debug mode.

  1. glance --debug index
  2. nova --debug list
  3. nova --debug show {UUID of the VM}

You will notice that the CLI makes HTTP requests to OpenStack APIs. Study the sequence of requests, request and response headers and bodies.

Development Process

Requirements

It's critical to understand the problems and know what you're expected to deliver. This is often half of the battle. Ask questions early on and check in with your mentor on a regular basis.

Design

Create a blueprint for your project using this template. Feel free to come up with your own format, but make sure to include the following:

  1. Reiterate the requirements as you understand them.
  2. Be specific on what will be delivered, and what is out of the scope.
  3. Design choices with pros and cons of each approach.
  4. Discuss API design, DB schema, etc.
  5. List dependencies.
  6. Track open issues.

A good design will also give you an idea of the level of effort required to implement the project.

Implementation

Coding Guidelines

Separate configurations from code.

Usernames, passwords, endpoints, etc., belong in a configuration file. These things change depending on environments and use cases, and should not be hard coded. When you find yourself using numbers and string literals in the code, consider whether it should be extracted to a configuration file instead. OpenStack has a great utility for reading from configuration files.

Log religiously

We rely on logs to debug issues in a production environment. Again, it's easy with OpenStack Oslo. Make sure to use appropriate log levels.

Use APIs

OpenStack has an extensive offering of APIs across all components. We suggest you stay with APIs as much as possible, so that the code works with any OpenStack deployment. If necessary you may query database tables directly, but keep it to a minimum.

Provide unit tests

You don't have to test every edge case. But the expectation is that unit tests should cover most of the code. With Python hopefully you won't have to write a lot of code.

Code review

There are benefits for both sides.

Project Structure

OpenStack projects follow a certain structure, which is also recommended for your project. We strongly suggest that you start with this sample project as a template.

Exercises

Browse the exercises folder for various exercises that you can pick up.