Arnaud Porterie describes the challenges in managing an open source project at scale.

1. Scaling Open Source Operations
Arnaud
Porterie
Sr. Engineering Manager, Docker

2. The people
Three groups
One culture
Agenda
The processes
Maintainership
Code & design
The tooling
Measure
Automate

3. The people

4. Who are the people in open source?
The people
Users
Contributors Maintainers

5. Who are the people in open source?
The people
Users
Contributors Maintainers
● Influence the roadmap and priorities
● Report usability issues and bugs (+1!)
● Want to learn about what is coming next

6. Who are the people in open source?
The people
Users
Contributors Maintainers
● Contribute something (code, docs, tests, …)
● Come to improve a project they use (hobbyist)
● Come to influence the project (professional)

7. Who are the people in open source?
The people
Users
Contributors Maintainers
● Organize the project
● Filter and review contributors input
● Influence by defining the roadmap

8. Contributors
(~800+ / 6M)
Who are the people in open source?
The people Users
(~6000+ / 6M)
● These groups aren’t mutually exclusive
● These groups aren’t mapped to employers
● These groups are very different in size!
Mtnr.
(~60)

9. Props to (some of!) the Docker maintainers
The people

10. The secret sauce for a healthy project
● Culture defines your open source community
● Of all things, culture is the one that scales best
○ Old habits die hard
○ Newcomers tend to follow community’s codes
○ It takes very few people to show the example to many
● Behave like you want your community to behave
Open source culture

11. The processes

12. The role of maintainers
● A maintainer is not a super contributor
○ Typically know the project best and happen to also be top contributors
● To the contrary, the maintainers role is to reach 0 open contributions
○ By interacting with community: coaching contributors, reviewing code
○ By improving the project infrastructure: guides, testing infra, tooling
● To maintainers, unreviewed contributions are a liability
Becoming a maintainer

13. How to identify those key community members?
● Golden rule: anybody should be able to become maintainer
○ The hobbyist dedicating a few hours every week
○ The professional paid by their employer to participate
● Docker’s approach: reward regular activity over extended period of time
○ Decision is vote-based (⅔ of maintainers + BDFL to approve)
○ But how to measure activity?
Becoming a maintainer

14. How to identify those key community members?
● Number of contributions is not the right metric to identify maintainers
● Our solution: number of issues & pull requests interacted with
○ Opening a pull request and commenting 10 times on it counts as 1
○ Commenting on someone else’s pull request also counts as 1
● Promotes people showing broader interest than their own contributions
Becoming a maintainer

15. ● Different groups
● Different expectations
● Conflicting priorities
What and who are you optimizing for?
Defining the process
Features Quality
Users
Contributors
Maintainers
Project pace

16. ● Quality first
● Review fast
● Minimize feature creep
Docker project tradeoffs
Defining the process
Features Quality
Project pace

17. What and who are you optimizing for?
● Docker open source processes mostly favor contributors
○ We don’t delay merges during code freeze
○ We carry patches that can’t be merged as is
○ We work hard to “reach a yes” (80% of contributions are merged)
● A happy contributor may eventually become a helpful maintainers
Defining the process

18. The goals of the process
● Minimizing frustration for the contributor...
○ By processing contributions in a timely manner
○ By “failing early” for contributions which won’t get merged
● … While preserving quality
○ Good automated testing and coverage
○ Two maintainers are required to merge
Example: code review process

19. Our approach: 4 steps workflow using GitHub labels
● Easy to tell what’s expected next
○ Is it a contribution we want?
○ Is it properly written, tested, and safe?
○ Is it documented?
○ Profit!
● Plus a few special labels for problematic contributions
○ Tests aren’t passing
○ Not progressing
Example: code review process

20. The pitfalls of “design by committee”
● Design decisions don’t scale (“too many cooks in the kitchen”)
● Golden rule: “No is temporary, yes is forever”
○ The default is “no” unless consensus can be reached
○ Reaching consensus gets harder as the group grows
● Divide and conquer: smaller groups on better delimited problems
Scaling design

21. Manage your processes as code
● Processes are just another tool
○ Document them as text files in the repository
○ Adjust the processes through pull requests
● For examples, see project/ subdirectory in github.com/docker/docker
Processes best practices

22. The tooling
Measure, automate, repeat

23. Metrics, metrics, metrics!
Measuring open source activity
● Many new questions will arise as a project scales
○ Who are the active members of the community?
○ Who is contributing to the project?
○ How fast do maintainers process contributions?
○ What are the most active repositories?
● We failed to find our ideal tool for that, so we built it

24. icecrime/vossibility-stack
Metrics, metrics, metrics!
Measuring open source activity

25. Automation
● GitHub webhooks are essential for open source automation
○ Docker uses NSQ to persist and fan-out messages
○ Allows for multiple listeners (queues) for a single repository (topic)
docker/leeroy Automate actions on GitHub events
docker/gordon-bot IRC bot to interact with Jenkins CI server
icecrime/poule Mass interact with pull requests

26. What’s next?
● Come learn how to contribute, or meet the maintainers!
Day 1
2:00pm Contribute 101: Engine / Swarm / Containerd
2.55pm Meet the maintainers: Engine / Swarm / Containerd
Day 2
1:30pm Contribute 101: Compose / Kitematic / Machine
2:25pm Meet the maintainers: Compose / Kitematic / Machine

27. Thank you!
@icecrime