Introduction to docker
17 likes2,492 views
This document provides an overview of a talk about Docker. It introduces Docker features like images, containers, and the workflow. It describes how Docker uses namespaces and control groups for isolation. It compares Docker to virtual machines and explains why Docker is popular. The document then demonstrates Docker through a tutorial of pulling an image, running a container, and viewing container logs. It also discusses the Dockerfile for automating builds.
![DOCKERFILE
FROM ubuntu
MAINTAINER me@me.me
# Install tmux
RUN
apt-get update && apt-get install tmux
RUN mkdir /home/hello
# Define working directory.
WORKDIR /home/hello
# Define default command.
CMD ["/bin/bash"]](https://image.slidesharecdn.com/introtodocker3-141002155212-phpapp02/85/Introduction-to-docker-59-320.jpg)
![DOCKERFILE
FROM ubuntu ← defines base imag
MAINTAINER me@me.me ← who is reponsible
# Install tmux
RUN
apt-get update && apt-get install tmux
RUN mkdir /home/hello ← let's run some
commands
# Define working directory.
WORKDIR /home/hello ← let's start here
# Define default command.
CMD ["/bin/bash"] ← default command to run
without arguments in run](https://image.slidesharecdn.com/introtodocker3-141002155212-phpapp02/85/Introduction-to-docker-60-320.jpg)
Introduction to docker
- 3. What will be in this talk - Overview of docker features - Overview of docker building blocks - Comparison to other solutions - Quick docker tutorial - Dockerfile tips
- 4. What will not be in this talk - Exploiting docker - Details of deploying docker infrastructure - Deep technical descriptions
- 6. -- EEaassyy ttoo lleeaarrnn -- CCooooll wwhhaallee -- WWrriitttteenn iinn ggoo
- 9. Features - images ● Package every app in the same box (dependencies, working everywhere) ● Isolate things from each other ● Standarized build procedure (Dockerfile)
- 10. Containers
- 11. Features - containers ● Managing containers – Running & stopping – Inspect, logs, top, ps – Save & load (from files) – Diff & commit ● Mounting volumens – Share data – Persistency ● Easy networking and linking containers
- 12. WWoorrkkss oonn eevveerryyoonnee''ss mmaacchhiinnee
- 15. Features - workflow ● Docker deamon and cli ● Docker hub and registry ● Image versioning (pull, commit, pull, layers)
- 19. Namespaces - GOAL One of the overall goals of namespaces is to support the implementation of containers, a tool for lightweight virtualization.
- 20. Namespaces - HOW Wrap a particular global system resource in an abstraction that makes it appear to the processes within the namespace that they have their own isolated instance of the global resource
- 21. Namespaces - Result Processes 'think' that they are the only processes on the system
- 22. Namespaces - Examples - pid - numbering - hierarchy - cannot kill / ptrace in other namespaces - net - 20 apaches at 80 - mount
- 23. CCoonnttrrooll ggrroouuppss hhttttpp::////bblloogg..ddoottcclloouudd..ccoomm//kkeerrnneell--sseeccrreettss--ffrroomm--tthhee--ppaaaass--ggaarraaggee-- ppaarrtt--2244--cc
- 24. Control groups Measure and limit resource usage for groups of processes
- 30. NNoott rreeaallllyy aa VVMM
- 31. WWhhyy ddoocckkeerr?? WWhhyy nnoott llxxcc??
- 32. WWhhyy ddoocckkeerr?? WWhhyy nnoott llxxcc??
- 33. WWhhyy ddoocckkeerr?? WWhhyy nnoott llxxcc??
- 34. WWhhyy ddoocckkeerr?? WWhhyy nnoott llxxcc?? http://stackoverflow.com/questions/17989306/what-does-docker-add-to-just-plain-lxc
- 36. PPuullll iitt!! $ docker pull busybox ● Search docker registry for repository of given name ● Downloads the repository ● Pulls only changes next time
- 37. PPuullll iitt!! $ docker pull busybox ● Search docker registry for repository of given name ● Downloads the repository ● Pulls only changes next time
- 38. PPuullll iitt!! $ docker pull busybox ● Search docker registry for repository of given name ● Downloads the repository ● Pulls only changes next time
- 40. RRuunn iitt!! $ docker run busybox:ubuntu- 14.04 echo "hello" ● Make sure that image is available (downloads if not found) ● Create a container ● Run a command
- 41. RRuunn iitt!! $ docker run -it busybox:ubuntu- 14.04 sh ● -it → makes container interactive ● Create a container ● Give you a shell access
- 42. More complicated example ● Run redis in a container ● Run it as a deamon ● Bind it to network ● Make storage persistent
- 43. RRuunn iitt!! $ docker run -d -v /var/docker/redis:/da ta -p 6379:6379 --name=redis dockerfile/redis ● -d → launch as deamon ● -v /var/docker/redi s:/data → mount directories ● -p 6379:6379 → forward ports
- 44. RRuunn iitt!! $ docker run -d -v /var/docker/redis:/d ata -p 6379:6379 --name=redis dockerfile/redis ● -d → launch as deamon ● -v /var/docker/red is:/data → mount directories ● -p 6379:6379 → forward ports
- 45. RRuunn iitt!! $ docker run -d -v /var/docker/redis:/da ta -p 6379:6379 --name=redis dockerfile/redis ● -d → launch as deamon ● -v /var/docker/redi s:/data → mount directories ● -p 6379:6379 → forward ports
- 46. WWaattcchh iitt!! $ docker ps Prints out information about docker containers
- 47. WWaattcchh iitt!! $ docker ps -a Prints out information about all docker containers: ● Running ● Exited
- 48. WWaattcchh iitt!! $ docker logs -t --follow romantic_enstein Get logs from stdin/stdout of container ● -t → show timestamp ● --follow → similar to tail -f
- 49. WWaattcchh iitt!! $ docker inspect romantic_enstein Get info about container ● Environment variables ● Ports ● Links
- 50. EEnntteerr iinnssiiddee!! - nsenter - ssh ● nsenter uses namespaces ● Ssh needs ssh server inside
- 51. TTiiddyy uupp - docker rm <container_id> - docker rmi <image_id> ● Docker images use lots of space ● Docker images can clog all your available space on server (no more pulling from registry)
- 52. TTiiddyy uupp $ docker ps -a | grep 'Exited' | awk '{print $1}' | xargs docker rm ● Get ids of exited containers ● Remove containers with given ids
- 53. RReeppoossiittoorryy wwoorrkkffllooww ● docker diff <container_id> ● docker commit <contaner_id> attero/stuff:my-tag ● Versioning! ● Tags ● Multiple versions ● Push & pull
- 54. WWhhaatt wwee lleeaarrnneedd ssoo ffaarr Repository workflow – Pull – Commit – Push Tidying up after containers – Rm – Rmi Monitoring – Ps – Logs – Inspect – Top Running containers – Interactive – Deamon – Mounting – Forwarding
- 57. DOCKERFILE
- 58. DOCKERFILE - Version control - Automation - Portability
- 59. DOCKERFILE FROM ubuntu MAINTAINER me@me.me # Install tmux RUN apt-get update && apt-get install tmux RUN mkdir /home/hello # Define working directory. WORKDIR /home/hello # Define default command. CMD ["/bin/bash"]
- 60. DOCKERFILE FROM ubuntu ← defines base imag MAINTAINER me@me.me ← who is reponsible # Install tmux RUN apt-get update && apt-get install tmux RUN mkdir /home/hello ← let's run some commands # Define working directory. WORKDIR /home/hello ← let's start here # Define default command. CMD ["/bin/bash"] ← default command to run without arguments in run
- 61. DOCKERFILE Every command in Dockerfile is run on a different container
- 62. DOCKERFILE Don't start services in dockerfile.
- 63. DOCKERFILE Cache! - use it - save lots of time - not changed layers are reused
- 64. DOCKERFILE - short - good base image - most changing things at the bottom
- 65. DOCKERFILE Every command in Dockerfile is run on a different container
- 66. Learning resources ● http://docs.docker.com/#installation-guides ● http://docs.docker.com/reference/builder/ ● http://docs.docker.com/reference/commandline/cli / ● https://crosbymichael.com/dockerfile-best-practic es.html ● http://docs.docker.com/articles/basics/ ● https://www.youtube.com/watch?v=XCVOxht34H s ● https://www.youtube.com/watch?v=9bvdc55xYdo
- 67. More Learning resources ● https://www.digitalocean.com/community/tutoria ls/docker-explained-how-to-containerize-python -web-applications ● http://phusion.github.io/baseimage-docker/ ● https://circleci.com/docs/docker ● http://docs.docker.com/userguide/usingdocker/
- 68. Q&A