Introduction to docker

Docker overview, building blocks and tutorial.

Transcript

1. Introduction to Introduction to docker 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
5. Easy to learn
6. - Easy to learn - Easy to learn - Cool whale - Cool whale - Written in go - Written in go
7. But seriously? But seriously?
8. Architecture changes http://martinfowler.com/articles/microservices/images/decentralised-data.png
9. Features - images • Package every app in the same box (dependencies, working everywhere) • Isolate things from each other • Standarized build procedure (Dockerfile)
10. Containers 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. Works on Works on everyone's everyone's machine machine
13. Isolation Isolation
14. Portability Portability
15. Features - workflow • Docker deamon and cli • Docker hub and registry • Image versioning (pull, commit, pull, layers)
16. Docker building Docker building blocks blocks
17. How it's How it's cooked? cooked?
18. Namespaces Namespaces http://blog.dotcloud.com/under-the-hood-linux-kernels-on- http://blog.dotcloud.com/under-the-hood-linux-kernels-on- dotcloud-part dotcloud-part
19. One of the overall goals of namespaces is to support the implementation of containers, a tool for lightweight virtualization. Namespaces - GOAL
20. 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 Namespaces - HOW
21. Processes 'think' that they are the only processes on the system Namespaces - Result
22. - pid - numbering - hierarchy - cannot kill / ptrace in other namespaces - net - 20 apaches at 80 - mount Namespaces - Examples
23. Control Control groups groups http://blog.dotcloud.com/kernel-secrets-from-the-paas-garage- http://blog.dotcloud.com/kernel-secrets-from-the-paas-garage- part-24-c part-24-c
24. Measure and limit resource usage for groups of processes Control groups
25. Docker vs VM Docker vs VM
26. Overhead http://www.zdnet.com/what-is-docker-and-why-is-it-so-darn-popular-7000032269/
27. Lightweight Lightweight And And fast fast
28. Sharing OS Sharing OS
29. Higher density Higher density
30. Not really a VM Not really a VM
31. Why docker? Why docker? Why not lxc? Why not lxc?
32. Why docker? Why docker? Why not lxc? Why not lxc?
33. Why docker? Why docker? Why not lxc? Why not lxc?
34. Why docker? Why docker? Why not lxc? Why not lxc? http://stackoverflow.com/questions/17989306/what-does-docker-add-to-just-plain-lxc
35. Docker tutorial Docker tutorial
36. Pull it! Pull it! $ docker pull busybox • Search docker registry for repository of given name • Downloads the repository • Pulls only changes next time
37. Pull it! Pull it! $ docker pull busybox • Search docker registry for repository of given name • Downloads the repository • Pulls only changes next time
38. Pull it! Pull it! $ docker pull busybox • Search docker registry for repository of given name • Downloads the repository • Pulls only changes next time
40. Run it! Run it! $ 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. Run it! Run it! $ 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. Run it! Run it! $ 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. Run it! Run it! $ 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. Run it! Run it! $ 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. Watch it! Watch it! $ docker ps Prints out information about docker containers
47. Watch it! Watch it! $ docker ps -a Prints out information about all docker containers: • Running • Exited
48. Watch it! Watch it! $ docker logs -t --follow romantic_enstein Get logs from stdin/stdout of container • -t → show timestamp • --follow → similar to tail -f
49. Watch it! Watch it! $ docker inspect romantic_enstein Get info about container • Environment variables • Ports • Links
50. Enter Enter inside! inside! - nsenter - ssh • nsenter uses namespaces • Ssh needs ssh server inside
51. Tidy up Tidy up - 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. Tidy up Tidy up $ docker ps -a | grep 'Exited' | awk '{print $1}' | xargs docker rm • Get ids of exited containers • Remove containers with given ids
53. Repository Repository workflow workflow • docker diff <container_id> • docker commit <contaner_id> attero/stuff:my-tag • Versioning! • Tags • Multiple versions • Push & pull
54. What we learned so far What we learned so far Repository workflow – Pull – Commit – Push Tidying up after containers – Rm – Rmi Monitoring – Ps – Logs – Inspect – Top Running containers – Interactive – Deamon – Mounting – Forwarding
55. Containers are nice
56. How about automation?
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