Basic introduction to Docker

1. Introduction to Docker
Bas Tichelaar

2. Knowledge check

3. Server

4. Server
OS

5. Server
OS
App

6. Server
App
70%

7. 45%
Server
App
70%
Server
App
40%
Server
App
25%

8. Virtualisation

9. Server
Hypervisor
OS

10. Server
Hypervisor
VM
Guest OS
App
OS

11. Server
VM
VM
App
App
VM
VM
App
App

12. 85%
Server
App
App
App
App
Server
App
App
App
App

13. Virtualisation pros
• Better resource utilisation
• Strong isolation between VM’s
• Automation and orchestration
• Live migration, high availability

14. Virtualisation cons
• Each VM contains overhead
• OS, SSH, logging, monitoring
• Starting a VM takes minutes
• Overhead compared to bare metal still high
• Especially I/O

15. Containers

16. Container vs VM
Server
Hypervisor
VM
Guest OS
App
Host OS
Server
Container
App
Host OS

17. Nothing new
• *BSD jails (2000)
• Solaris zones (2004)
• Linux LXC (2006)
• Google lmctfy (2013)

18. Container pros
• Faster lifecycle compared to VM’s
• Almost no overhead
• Smaller size
• Starts instantly

19. Container cons
• Complex to configure
• Security isolation not as good as VM’s
• Must run on Linux, Solaris or *BSD

21. Docker
• Container management for Linux
• Abstraction for DevOps workflow
• Adds images, image repository and version control
to containers

22. Docker by numbers
• 60 400+ million downloads
• 40.000 75.000 300.000+ Dockerized applications
• 40.000 50.000 third party projects on Github
• $55 $150 million in funding

23. Docker components

24. Basics
Dockerfile Docker image
Docker
container
build
deploy
Docker Hub
publish

25. Dockerfile
FROM stackbrew/ubuntu
RUN apt-get update && apt-get install -y
apache2 && apt-get clean
ENV APACHE_RUN_USER www-data
ENV APACHE_RUN_GROUP www-data
EXPOSE 80
CMD ["/usr/sbin/apache2", "-D", "FOREGROUND"]

26. Docker image
• Result of ordered actions
• Add file
• Expose port
• Run command
• Layered result, like GIT

27. Docker image
Result
FROM ubuntu:12.04
SET ENV …
RUN apt-get …
CMD /usr/bin/apache2

28. Docker Hub
• Contains Docker images
• Public Registry
• Create your own private
registry
• New: Docker Enterprise Hub

29. Creating a Docker image
Linux/OSX/Windows
Docker client
Linux
Docker daemon
docker build -t apache2 .
apache2
Docker image
Dockerfile

30. Running a Docker container
Linux/OSX/Windows
Docker client
Linux
Docker daemon
docker run apache2
apache2
container

31. Docker innovations
• Simplifies container deployment
• Reduces complexity of managing containers
• Client <-> Server components

32. Separation of concerns
Developers
Inside the container:
code
libraries
package manager
app
data
Operations
Outside the container:
logging
remote access
networking
monitoring
security

33. Docker machine
machine up
Docker host
Docker host
Docker host

34. Docker Swarm
Docker client
Docker swarm
Docker host Docker host Docker host
Developer laptop Local datacenter Amazon EC2

35. Docker compose
containers:
web:
build: .
command: python app.py
ports:
- "5000:5000"
volumes:
- .:/code
links:
- redis
environment:
- PYTHONUNBUFFERED=1
redis:
image: redis:latest
command: redis-server --appendonly yes

36. Working webapp
Linux/OSX/Windows
Docker client
Linux
Docker daemon
docker up
web redis
link
port 5000
User

37. Docker Hub Enterprise
• On premise Docker Hub
• Image provenance
• Audit logs
• System health monitoring

38. Example pipeline

39. Code
GIT
Build
Docker
image
Build
code
Unit tests
Publish
Docker
image
Pull
Docker
image
Run
Docker
container
Commit
Write
Build
Test
Deploy
Run
integration
tests
Pull
Docker
image
Run
Docker
container
registry

40. Challenges
• Running Docker in production
is still hard
• Security
• Wiring containers together
• What runs where?

41. The future of Docker
• Batteries included but removable
• Adoption by cloud providers
• Microsoft: Docker on Windows

42. –Solomon Hykes, founder of Docker
“The real value of Docker is not technology, it’s
getting people to agree on something”

43. Questions?
bas@tichelaar.io
www.nauts.io