The document provides an overview of Docker, detailing its history, advantages over virtual machines, and essential commands for installing and using Docker. It explains the concept of containers, how to work with Docker images and containers, and touches on writing a Dockerfile. Additionally, it addresses limitations and misconceptions related to Docker, and suggests resources for further learning.

1. Docker by Demo
by Srikanth Seshachary

2. What is Docker?

3. History of LXC (Linux Containers)

4. cgroups

5. namespaces

6. Docker, a high level API

7. Why do we need Docker?

8. dependencies as versioned code

9. isolation of processes

10. speed

11. debugging

12. pluggability

13. devops – a process enforcer

14. devops – a tool between rpm,
deb and ansible, chef, puppet

15. devops – a process enforcer

16. What’s wrong with VMs?

17. speed

18. new vm = minutes,
new container = seconds

19. vms = separate kernel,
containers = shared kernel (can have
different base image)

20. duplicate services (cron, syslog)
need to be run for each role

21. Installing Docker

22. only 64-bit supported

23. kernel 3.8

24. sudo yum install docker-io
sudo service docker start

25. Downloading (aka pulling)
Images

26. $ sudo docker pull ubuntu
$ sudo docker images

27. Launching Containers

28. $ sudo docker run -i -t ubuntu /bin/bash
$ sudo apt-get install python3
$ sudo docker ps
$ sudo docker commit <container_id> image

29. Docker Repositories

30. local private images

31. The Docker Hub

33. Writing Your First Dockerfile

34. # Dockerfile
FROM ubuntu
MAINTAINER James Turnbull "james@example.com"
RUN apt-get update
RUN apt-get install -y nginx
RUN echo 'Hi, I am in your container'
>/usr/share/nginx/html/index.html
EXPOSE 80
ENTRYPOINT ["/usr/sbin/nginx"]
CMD ["-h"]

35. $ sudo docker build -t="user/nginx" .
$ sudo docker run -t -i user/nginx
$ sudo docker run -t -i user/nginx -g "daemon off;“
$ sudo docker port <container>

36. Issues/Limitations/Misconceptio
ns

37. lack of image inheritance–
composing multiple images (for
example, ruby and nginx)

38. yet another tool – dockerizing
your app takes time

39. not every app can be dockerized

40. you still need configuration
management tools like ansible or
puppet

41. orchestration isn’t avoided
either

42. Where do you go from here?

43. the docker book, james turnbull

44. try dockerizing one of your
applications

45. References
• http://knitatoms.net/2013/12/benefits-of-docker-for-app
• https://devopsu.com/blog/docker-misconceptions/
• https://stackoverflow.com/questions/16047306/how-is-d