Talk I gave at the Leeds Devops meeting in June 2015 about the internals Docker. Followed it with a performance of my song about Nagios: http://www.leedsdevops.org.uk/post/122413169155/john-leach-plays-his-nagios-song-at-leeds-devops

1. Docker
Please contain your
excitement
Docker
Please contain your
excitement
John Leach
john@brightbox.com
@johnleach
Brightbox
www.brightbox.com

5. VirtualisationVirtualisation
Host hardware
Host kernel
Virtual machine process
Virtual hardware
Virtual machine kernel
Your application

6. DockerDocker
Host hardware
Host kernel
Your application

7. Linux processesLinux processes
Host hardware
Host kernel
application1 application2 application3

8. Linux NamespacesLinux Namespaces
Host hardware
Host kernel
application1 application2 application3

9. Physical RAM
process
filesystem
process process
network

10. Physical RAM
process
filesystem
Logical RAM
process process
Logical RAM Logical RAM
network

11. Physical RAM
process
filesystem
Logical RAM
process process
Logical RAM Logical RAM
network
FS namespace net namespaceFS namespace net namespace FS namespace net namespace

12. Network per processNetwork per process

13. Filesystem per processFilesystem per process

14. Filesystem per processFilesystem per process

15. unshare commandunshare command

16. UTS NamespaceUTS Namespace

17. Network NamespaceNetwork Namespace

18. Process NamespaceProcess Namespace

19. Mount NamespaceMount Namespace

20. User NamespaceUser Namespace

21. IPC NamespaceIPC Namespace

22. nsenternsenter

23. Inter-namespace
communication
Inter-namespace
communication

24. cgroupscgroups

25. Namepaces + cgroupsNamepaces + cgroups
How can we bring this all together?

26. LXC – Linux ContainersLXC – Linux Containers

27. Docker vs. LXCDocker vs. LXC
What makes Docker different?

28. DockerDocker

29. Docker imagesDocker images

30. Docker Images: LayersDocker Images: Layers
511136ea3c5a/
f3c84ac3a053/
q1a958a24818/
9fec74352904/
d0955f21bf24/
Container layer a65ee08f6/
Overlay fs
Hard linked together
Process

31. Container layersContainer layers

32. docker commitdocker commit

33. docker commitdocker commit

34. docker savedocker save

35. DockerfileDockerfile
FROM ubuntu
RUN apt-get update -qqy
RUN apt-get install -qqy cowsay
ENV MESSAGE “nothing to say”
CMD sh -c "/usr/games/cowsay $MESSAGE"

36. Docker Images: LayersDocker Images: Layers
511136ea3c5a/
f3c84ac3a053/
q1a958a24818/
9fec74352904/
d0955f21bf24/
Overlay fs
Hard linked together
FROM ubuntu
RUN apt-get update -qqy
RUN apt-get install -qqy cowsay
ENV MESSAGE “nothing to say”
CMD sh -c "/usr/games/cowsay $MESSAGE"

39. docker pushdocker push

40. docker pulldocker pull

41. NetworkingNetworking

42. Persistent storage with
Volumes
Persistent storage with
Volumes

43. Service discoveryService discovery

44. The Future of DockerThe Future of Docker

45. Docker
Please contain your
excitement
Docker
Please contain your
excitement
John Leach
john@brightbox.com
@johnleach
Brightbox
www.brightbox.com