Docker intro for developers

1. Dockerizing development
workflow
ITRally
16 May 2015
Orest Ivasiv
Software engineer, Softserve
Docker hobbyist

2. Outline
1. What is Docker?
2. Internals of Docker
3. Docker basic commands
4. Sample usage

3. History
source Wikipedia
Docker was released as open source in March 2013

4. History
February 2013: private repo, with liveral access (~200 people had access and helped to
review, contribute, give feedback)
March 2013: Docker 0.1 release at PyCon:
- requires LXC, AUFS;
- works on Debian/Ubuntu kernels
June 2014: Docker 1.1, released at DockerCon
May 12 2015: Docker 1.6.2, release 3 days ago

5. Docker Community
21500+ Github Stars
900+ Github Contributors
~50% of the commits are done by community

6. What is Docker?
Docker is an open source platform to automate development cycle of applications
inside software containers.
Build → ship → run any app, anywhere
Build: package your application in a container
Ship: move that container from a mashine to another
Run: execite that container (i.e. your application)
Any application: anything that runs on Linux
Anywhere: local VM, cloud instance, bare metal, etc.

7. Docker Host OS requirement
Linux kernel 3.8+
Union file system - AUFS, btrfs, vfs or DeviceMapper

8. Docker vs VM
Containers vs VMs. Diagram source: Docker Inc.
There's a great StackOverflow answer showing the differences(http://stackoverflow.com/questions/16047306/how-
is-docker-io-different-from-a-normal-virtual-machine)

9. Docker vs VM
Startup time is less for Docker than VMs (super fast)
Docker images have much smaller size
Snapshot process is faster in Docker than VMs
Docker images have more portability
Docker provides versioning of images
Docker images do not have states
Don't need SSH for access

10. Docker vs native
Docker helps to avoid lib version conflicts
Docker has no or minimal overhead while using resource for visualization

11. Docker Linux technology stack
Docker can use different interfaces to access virtualization features of the Linux kernel. Diagram source: Docker Inc.

12. Docker architecture
Docker Client
Docker Daemon
Docker Registry

13. Docker Internals
Docker image(http://docs.docker.com/terms/image/)
Docker layer(http://docs.docker.com/terms/layer/)
Docker container(http://docs.docker.com/terms/container/)
Docker repository(http://docs.docker.com/terms/repository/)
Docker registry(http://docs.docker.com/terms/registry/)

14. Docker Layers

15. Docker Layers

16. Docker Layers

17. Docker Layers

18. Use cases
1. Docker for local application development and test
Worksonmymachine→Worksagainonmymachinetomorrow→Worksonatestmachine
2. Docker for development team collaboration
Worksonmymachine→Worksonyourmachine
3. Docker for continuous integration
-Complicatedconfigurationofvarioustypesofbuildjobs(e.g.,Maven,GCCandJUnit)
-Needforacleanenvironmentforthebuildortest,toeliminatepossiblecontaminants
-ManagingthetotalexecutiontimeoftheCIworkflow
4. Docker for production application deployment
Worksonmymachine→WorksonQAmachines→Works(thesame)onproductionhardware
→Staysworking(securely)ontheproductionenvironment
5. Docker for creating a private PAAS

19. Docker vs Boot2Docker

20. Demo time

21. References
Official Docker documentation(http://docs.docker.com/)
Docker Cheat Sheet(https://github.com/wsargent/docker-cheat-sheet)
Docker Use cases - Article(http://blogs.gartner.com/richard-watson/ok-get-dockers-great/)
Linux Containers(https://linuxcontainers.org/)
Introduction to Docker, December 2014 "Tour de France" Bordeaux Special Edition,
Jérôme Petazzoni(http://www.slideshare.net/jpetazzo/introduction-to-docker-december-2014-tour-de-france-bordeaux-special-edition)
Official hosted registry https://hub.docker.com/(https://hub.docker.com/)

22. Thank you
Orest Ivasiv
Software engineer, Softserve
Docker hobbyist
halyph@gmail.com(mailto:halyph@gmail.com)
http://halyph.com(http://halyph.com)
@halyph(http://twitter.com/halyph)