Contributing to OpenStack
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Transcript of Contributing to OpenStack
Tutorial on Contributing to OpenStack
Dr. Devdatta KulkarniPTL, OpenStack Solum
Agenda
• Part I – Introductions– Introduction to OpenStack
• Part II – Deep dive of a OpenStack project - Solum
• Part III– Contributing to OpenStack– OpenStack CI system– Development best practices– Hands-on exercise
• Questions and Answers
Agenda
• Part I – Introductions– Introduction to OpenStack
• Part II – Deep dive of a OpenStack project - Solum
• Part III– Contributing to OpenStack– OpenStack CI system– Development best practices– Hands-on exercise
• Questions and Answers
Introduction
• Me– Dr. Devdatta Kulkarni– I go by Devdatta or Dev– Working at Rackspace USA– First contributor on Solum– Currently Project Team Lead (PTL) of Solum for Mitaka cycle– PhD, University of Minnesota Minneapolis
• You
Introduction to OpenStack
What is OpenStack?
A family of “open” projects that together enable different aspects of cloud computing
Openness of OpenStackhttps://wiki.openstack.org/wiki/Open
• Open source• Open design• Open development• Open community
OpenStack family
• Family of projects enabling different aspects of cloud computing– Authentication and authorization layer
• Keystone– Infrastructure-as-a-service layer
• Nova, Glance– Storage layer
• Swift, Cinder– Networking layer
• Neutron– Platform-as-a-service layer
• Solum, Heat, Murano, Mistral, Trove
• Project types– OpenStack big tent vs. OpenStack related projects
OpenStack by numbers
• 49 projects in OpenStack big tent• Several hundred organizations involved • Several thousand developers participating
Agenda
• Part I – Introductions– Introduction to OpenStack
• Part II – Deep dive of a OpenStack project - Solum
• Part III– Contributing to OpenStack– OpenStack CI system– Development best practices– Hands-on exercise
• Questions and Answers
What is Solum?
OpenStack project that provides easy mechanism for application developers to deploy and run their applications on OpenStack starting from application’s source code
Why should you care? (the value proposition)– For operators, Solum provides ability to make your OpenStack cloud more
useful for your clouds’ application developers by simplifying the process of deploying applications to it
– For developers, Solum provides an easy-to-use platform for building, testing, and deploying applications on OpenStack clouds
Project goals
Application Stack FlexibilityAbility to support applications written in different languages and using different application frameworks
Developer ProductivityAbility to perform CI/CD, integration with github
Add-On Services ExtensibilityAbility to support different add-on services
Application PortabilityAbility to deploy applications across different OpenStack clouds (use native OpenStack services)
Project details
• Wiki:https://wiki.openstack.org/wiki/Solum
• Meetings:Tuesdays 1700 UTC in #openstack-meeting-3
• IRC:Channel: #solum on freenode
• Code:https://github.com/openstack/solumhttps://github.com/openstack/python-solumclient
Solum abstractions
• App• Languagepack (LP)• Deployment Unit (DU)• Workflow• Add-on
Solum abstractions - App
Declarative application definition
• source code repository• run command• port• languagepack
version: 1name: cherrypydescription: python web applanguagepack: pythonsource: repository: https://github.com/rackspace-solum-samples/solum-python-sample-app.git revision: masterworkflow_config: run_cmd: python app.pyports:- 80
Solum abstractions - Languagepack (LP)
• Docker image which contains application specific build and runtime libraries
• A LP needs to implement Solum’s languagepack contractA well-known file available at a known location on the languagepack image
/solum/bin/build.sh
• How to build a LP?Dockerfile
• Operator-defined or user-defined
Solum abstractions - Languagepack Example: Python
FROM ubuntu:preciseMAINTAINER Murali Allada <[email protected]>
RUN apt-get -yqq updateRUN apt-get -yqq install python-pipRUN apt-get -yqq install python-dev
COPY build.sh /solum/bin/
https://github.com/rackspace-solum-samples/solum-languagepack-python
#!/bin/bash
# Check if pip is installedpip help[[ $? != 0 ]] && echo python-pip is not installed. && exit 1
# Install app dependenciescd /apppip install -r requirements.txt
build.shDockerfile
Solum abstractions - Deployment Unit (DU) (1/2)
• Docker image that is formed from the languagepack image with application’s source code added to it
DU = LP + application source code
• Solum guarantees the DU contractApplication source code available at a known location on the DU image /app
• How to build a DU?– Construct Dockerfile with languagepack as the base image, application source code
injected, run command as the entry point– Build the DU image from this Dockerfile
18
Solum abstractions - Deployment Unit (DU) (2/2)
• Building a DU– Start from the specified languagepack LP– Specify execution of languagepack’s ‘build.sh’– Inject application source code– Use the run command specified in app definition as the default Entrypoint to
run the DU
• LP and DU storageGlance, Swift, Docker registry
Solum abstractions - Workflow
• Abstraction to represent execution of application deployment consisting of one or more workflow stages
• Supported workflow stages– Build DU (and store it for future use)– Run unit tests, build DU– Run unit tests, build DU, deploy DU (if unit tests pass)– Build DU, deploy DU– Deploy a previously built DU (not yet available)
• A workflow can be triggered from github webhooks
Solum abstractions - Add-ons
• Services needed by an applicationE.g.: relational database such as Trove
• DU parametersSolum supports ability to pass service’s connection parameters
to application DU
Architecture and system details
High-level architecture
SolumAPI
SolumWorker
SolumDeployerQueue Queue
Queue
SolumConductor
Heat
Solum Database
Glance, Swift, Docker Registry
Builds LP and DU Deploys DU
- Decoupled architecture
- Asynchronous communication
Agenda
• Part I – Introductions– Introduction to OpenStack
• Part II – Deep dive of a OpenStack project - Solum
• Part III– Contributing to OpenStack– OpenStack CI system– Development best practices– Hands-on exercise
• Questions and Answers
Contributing to OpenStack
Tools/Systems
• Gerrit: Code review system– https://review.openstack.org/
• Launchpad: Work (bugs/blueprints) tracking system– https://launchpad.net/
• Github: Code repository– https://github.com/openstack
• Git: Code contribution• Mailing list: openstack-dev
– http://lists.openstack.org/cgi-bin/mailman/listinfo/openstack-dev• IRC: chat.freenode.net
Setup steps (1/2)
• http://docs.openstack.org/infra/manual/developers.html• Create Launchpad account• Join OpenStack foundation as foundation member• Sign individual contributor’s license agreement• Install git-review• Install git• Run git review -s
Setup steps: Problems and troubleshooting
• Problem:We don't know where your gerrit is. Please manually create a remote
• Solution:– Create a username in gerrit if not already created– Manually set gerrit remote. E.g.: git remote add gerrit "ssh://[email protected]:29418/openstack/solum.git”
Setup steps: Problems and troubleshooting
• Problem: Problem running 'git remote update gerrit’
Fetching gerrit Permission denied (publickey). fatal: Could not read from remote repository.• Solution:– Generate sshkey and add it to gerrit– ssh-keygen
Steps to submit a patch
• Create a Launchpad bug or assign an existing bug to yourself• Fixing the bug– Iterative process
• Understand the issue (be in touch with project developers on project’s IRC channel or on openstack-dev mailing list)
• Design solution• Write code• Write tests• Commit code• Provide good commit message• Submit patch for review
Steps to merge a patch
• Patch needs to pass configured automated tests• Patch needs to get two +2 votes• Patch needs to be approved for merging by project’s
core reviewer
OpenStack CI System
Continuous Integration of patches
• Systems involved:– Zuul– Gerrit– Jenkins– Github
• Pre-merge checking– Patch is merged to master only if all the configured tests
pass
OpenStack’s CI setup
Gerrit Zuul Jenkins
Github
2 3
45
1Patchsubmittedfor review
Patch picked upfor testing Tests ran on the patch
Jenkins gives its vote
Codemerged
Patch review page details
Gerrit: Patch that fails gate tests
Development best practices
Best practices, tricks, tips
• Devstack• Vagrant and Virtualbox• Python • Screen• Debugging• Git
Devstack
• OpenStack environment consisting of all the openstack-services– Keystone, Nova, Heat, Solum, etc.
• Can be run within a virtual machine or independently
• Useful for development
Vagrant and VirtualBox
• Vagrant– Configuration management tool for configuring virtual machines
• VirtualBox– Virtualization system
• Spinning up a development environment using Vagrant + VirtualBox– https://github.com/rackerlabs/vagrant-solum-dev– git clone <solum-vagrant-repo>– vagrant up --provision
Setting up Solum development env
• Develop on Host, debug on the VM• Install Vagrant and Virtualbox• Clone solum and python-solumclient repositories on the
Host• Set following environment variables:– SOLUM=<path on Host system to solum repo>– SOLUMCLIENT=<path on Host system to python-solumclient repo>
• vagrant up --provision• vagrant ssh
Python
• PyCharm IDE• pdb– Put breakpoint in the code where you want to break• import pdb; pdb.set_trace()
– pdb commands• s: Execute the current line, stop at first possible occasion• c: Continue execution, only stop when a breakpoint is
encountered• https://docs.python.org/2/library/pdb.html
Testing
• Run tests locally before submitting patch for review– From within solum directory• tox –epep8• tox –epy27
• Tox– Command line tool for running tests within virtualenv
Code paths on Devstack
• solum/opt/stack/solum
• python-solumclient/opt/stack/python-solumclient
• Solum logs– /var/log/solum/deployer– /var/log/solum/worker
• Devstack logs (of various screen sessions)– /opt/stack/logs/
Screen
• Program that allows sharing physical terminal between different processes
• Entering Solum’s screen session in Devstack– screen –x stack
• Screen commands– Move to next window: Ctrl+a n– Move to previous window: Ctrl+a p– See all windows: Ctrl+a “– Enter scrollback/copy mode: Ctrl+a [– Leave scrollback/copy mode: Ctrl+a ]– http://www.pixelbeat.org/lkdb/screen.html
Debugging
• Debug code/feature– Put breakpoints in the code– Invoke code-under-test from CLI– Use screen to enter breakpoint and then debug using
Pdb• Debug failing functional test– https://review.openstack.org/#/c/254344/
• Debug failing unit test
Git
• Creating dependent commits• Squashing commits– git rebase -i HEAD~<number-of-commits>– pick/squash/edit
• Updating dependent commit and submitting for review
• https://ask.openstack.org/en/question/31633/gerrit-best-way-to-make-a-series-of-dependent-commits/
Hands-on exercise
• Submit first patch to OpenStack (45 minutes)
• https://etherpad.openstack.org/p/solum-low-hanging-fruit-bugs
Questions