2. CI & Docker
An experience building
complex CI environments
Patxi Gortázar
francisco.gortazar@urjc.es
@fgortazar

3. Bio
Project Coordinator at @elastestio EU project
Devops @ Kurento
Teaching Distributed Systems @ URJC
@fgortazar
https://es.linkedin.com/in/franciscogortazar

4. Consultancy / Training
Cloud Computing
Distributed Systems
Web Technologies
Extreme Programming
Testing / Git / Jenkins
Software Architectures
Concurrent Programming
Open source elastic platform
for end to end testing
http://codeurjc.es http://elastest.io
Advanced log management
Test orchestration
Test execution comparison
Web and Mobile testing
Security testing
IoT testing
Performance testing

5. Why
A media server for real time video communication
The software under test

6. WebRTC

7. Software under test

8. Software under test

9. Software under test
So Kurento is…
• A media server
• APIs for managing connections in a WebRTC
communication
• Tutorials
• Applications
• Testing
– Under many scenarios
– Even more testing in different environments

10. A soup of technologies

11. Some numbers
• 30 code repositories
• ~400 Jenkins jobs
• +1,000 tests
• +20 different environments to test
• +80 artifacts to be deployed at release time

12. Feasible infrastructures
Cloud
• Public or private
• 20 environments = 20 different VMs
• Cost increases with each new environment!!
• Effort increases with each new environment to
configure (ops)!!
• Time-to-market increases also!!

13. Kurento’s CI Infrastructure
Building Debian packages
• 2 Ubuntu Trusty VMs
• 4 Ubuntu Xenial VMs
• 2 Ubuntu latest VMs
Building clients
• 1 node mvn & jdk 7 &
node 4
• 1 node mvn & jdk 7 &
node 6
• 1 node mvn & jdk 8 &
node 4
• 1 node mvn & jdk 8 &
node 6

14. Further problems
• Developers are pushing hard towards ops/devops
to include changes in infrastructure
• Changes can hardly be reverted (possible, but…)
• Hard to test locally
– Works in my machine effect
• Wasted resources
• And at the same time, insufficient resources
Can we do better?

15. Simplifying CI with Docker

16. How
• Leverage Jenkins Pipeline
– CI configuration hosted within code repositories
– Docker support out-of-the-box
– Jenkins jobs launch containers on top of VMs
– VMs have all the same minimum configuration:
Docker

17. Current Infrastructure
1 VM Jenkins Master
N VMs Jenkins Workers (running Docker)
2 VM configurations

18. Where are my environments?
• The different environments are encapsulated as Docker
images
• Docker images can be used in any of the workers
• Docker images can be used in your laptop
• Docker images are versioned, easy to maintain, easy to build
• Any version can be used
• Several environments can be run in parallel in the same VM:
isolation

19. Which environments do I need?
You need images for your builds
You need images for your applications
You need images for your tests

20. Images for builds
• Heavy images (> 400Mb)
• One image per tool version: jdk7, jdk8
• Download ahead of time
– As opposed to downloading at build time
– E.g., downloading images in a nightly job

21. Images for builds
With Docker it’s easier to tame matrix envs
• Consider building a project using…
– Ubuntu
• Trusty
• Xenial
• Zesty
– Java
• JDK 7
• JDK 8
• JDK 9

22. Images for builds
What if we need to mix…
• JDK
• Maven
• Node
• Npm
• Bower
… in the same environment?

23. Images for applications
You're ready to ship your application as a
container (optional)
• Choose lightweight containers
– Docker is focusing on lightweight containers
leveraging Alpine Linux
• Include just what your application needs
– Leverage new multi-stage build in Docker
• Think about dependencies (databases, caching...)

24. Images for testing
• You can run browsers within a container
– https://github.com/SeleniumHQ/docker-selenium
• Available images
– selenium/hub
– selenium/node-chrome
– selenium/node-firefox
– selenium/node-chrome-debug
– selenium/node-firefox-debug

25. Images for testing
• Unfortunately they're a bit out of date
– See https://github.com/SeleniumHQ/docker-
selenium/issues/229#issuecomment-253334224
• Don't worry
– It's easy to build them with the latest browser
– We can test against latest release, beta and canary
• Alternatives
– TestContainers: https://www.testcontainers.org/

26. Testing with multiple containers
Orchestration...
• docker compose
– Require to know the number of containers in
advance
• Otherwise, docker run
• Cleaning containers and images with spotify-gc

27. Testing with multiple containers
Orchestration...
• End-to-end tests
– 1-5 browsers
– Test scenario is run several times with different
configurations
• Chrome (stable, beta, canary)
• Firefox (stable, beta)
• …

28. Testing with multiple containers
Orchestration...
• Tests can include a Docker client for flexibility:
– Start & stop containers
– Container inspection
– Gathering logs
– Managing Volumes
– Managing environment variables

29. Testing with multiple containers
Orchestration...
• Network topologies
– Specific network plugins
– Handcrafted networks
• docker run --net=none …  Ugly hack!!
• Better use network plugins

30. Testing with multiple containers

31. Challenges
• Gathering data
– Logs from several containers
– Metrics (CPU, memory, network…)
– Files generated (browser recording)
• Integrating data with test execution
– Comparing some data across several executions
– Data integration

32. Challenges
• Reproducing real-world conditions
– Failing nodes
– Failing networks
– Network bandwidth (4G, 5G, DSL)
– Network topologies (NAT traversal, firewalls, …)
– High loads (bursting CPUs)

33. Consultancy / Training
Cloud Computing
Distributed Systems
Web Technologies
Extreme Programming
Testing / Git / Jenkins
Software Architectures
Concurrent Programming
Open source elastic platform
for end to end testing
http://codeurjc.es http://elastest.io
Advanced log management
Test orchestration
Test execution comparison
Web and Mobile testing
Security testing
IoT testing
Performance testing

34. Bio
Coordinator http://elastest.io/
Devops @ Kurento
Teaching Distributed Systems @ URJC
@fgortazar
https://es.linkedin.com/in/franciscogortazar