Docker - Lightweight Virtualization
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This document discusses Docker, a tool that allows applications to be isolated and run in lightweight containers. It introduces key Docker concepts like images, containers, repositories and registries. It provides examples of using Docker commands like docker run, docker pull, docker push and docker build. It compares containers to virtual machines and explains how Docker utilizes namespaces and cgroups to provide isolation. Finally, it outlines a Docker workflow and references additional Docker resources.
![Docker Vocabulary
• Registry $ docker pull ubuntu:12.04
Pulling repository ubuntu
c0fe63f9a4c1: Pulling dependent layers
511136ea3c5a: Download complete
6170bb7b0ad1: Download complete
79fdb1362c84: Downloading [===> ]56 MB/66.64 MB 10m9s](https://image.slidesharecdn.com/docker-140514103531-phpapp02/85/Docker-Lightweight-Virtualization-12-320.jpg)
![Docker Vocabulary
• Dockerfile $ cat Dockerfile
FROM ubuntu:12.04!
!
MAINTAINER Mehdi Hasan "mehdi@team.okdo.it"!
!
RUN apt-get -y install python-software-properties!
RUN add-apt-repository ppa:chris-lea/node.js!
RUN apt-get update!
RUN apt-get -y install python g++ make nodejs!
$ docker build -t mehdi/nodejs .
There is a
trailing dot
$ docker push mehdi/nodejs
Image c0fe63f9a4c1 already pushed, skipping
Image 5ff6986cd174 already pushed, skipping
Image 3867fae91348 already pushed, skipping
Image 4574f80c91e4 already pushed, skipping
Image 37c2cc34fa4e already pushed, skipping
757db77867dd: Image successfully pushed
Pushing tag for rev [757db77867dd] on {https://
registry-1.docker.io/v1/repositories/mehdi/nodejs/tags/
latest}
Any idea
why these
images are
skipped?](https://image.slidesharecdn.com/docker-140514103531-phpapp02/85/Docker-Lightweight-Virtualization-15-320.jpg)
Docker - Lightweight Virtualization
- 2. Why?
- 3. That eternal crap…! (i.e Having no idea what’s wrong)
- 4. Passing on the headache! Not the solution
- 5. Some use cases • Solving dependency hell • Configure once, run anywhere • Continuous integration • Create sandboxed app • Run your own PaaS
- 7. Isolation Portability Provisioning Hypervisors/VM Chef, Puppet, Ansible Your app, libraries Docker
- 8. Docker vs. VM Hardware Linux/Kernel Container Container Container Container Container Container Hardware Linux/Kernel VM Linux/Kernel VM Linux/Kernel VM Linux/Kernel VM Linux/Kernel Shared Resource, Lightweight, Portable, Fast to boot Dedicated Resource, Heavy, Not portable, Comparatively slower boot
- 9. Under the Hood LXC Dream inside dream inside dream…. (The Inception in Linux) Namespaces & cgroups Isolated pid, net, uid…. Copy-on- write Filesystem AUFS, btrfs, ZFS….
- 11. Docker Vocabulary • Repository • Image • Tag $ docker images ubuntu REPOSITORY TAG IMAGE ID ubuntu 10.04 9cc9ea5ea540 ubuntu 12.04 9cd978db300e ubuntu 12.10 5ac751e8d623 ubuntu 13.04 eb601b8965b8 ubuntu 13.10 9f676bd305a4 ubuntu latest 9cd978db300e ubuntu lucid 9cc9ea5ea540 ubuntu precise 9cd978db300e ubuntu quantal 5ac751e8d623 ubuntu raring eb601b8965b8 ubuntu saucy 9f676bd305a4
- 12. Docker Vocabulary • Registry $ docker pull ubuntu:12.04 Pulling repository ubuntu c0fe63f9a4c1: Pulling dependent layers 511136ea3c5a: Download complete 6170bb7b0ad1: Download complete 79fdb1362c84: Downloading [===> ]56 MB/66.64 MB 10m9s
- 13. Docker Vocabulary • Index $ docker login Username: mehdi Password: Email: mehdi@team.okdo.it Login Succeeded
- 14. Docker Vocabulary • Container $ docker run ubuntu:12.04 echo Hello World Hello World $ docker run -i -t ubuntu:12.04 /bin/bash root@a09d485c9a9f:/# uname -a Linux a09d485c9a9f 3.13.3-tinycore64 #1 SMP Wed Mar 26 03:16:13 UTC 2014 x86_64 x86_64 x86_64 GNU/Linux ! root@a09d485c9a9f:/# $ docker ps CONTAINER ID IMAGE COMMAND CREATED STATUS ! f0638f0a1c7a ubuntu:12.04 /bin/bash 46 minutes ago Up 4 seconds Tip: Press Ctrl+P and Ctrl+Q to detach running containers
- 15. Docker Vocabulary • Dockerfile $ cat Dockerfile FROM ubuntu:12.04! ! MAINTAINER Mehdi Hasan "mehdi@team.okdo.it"! ! RUN apt-get -y install python-software-properties! RUN add-apt-repository ppa:chris-lea/node.js! RUN apt-get update! RUN apt-get -y install python g++ make nodejs! $ docker build -t mehdi/nodejs . There is a trailing dot $ docker push mehdi/nodejs Image c0fe63f9a4c1 already pushed, skipping Image 5ff6986cd174 already pushed, skipping Image 3867fae91348 already pushed, skipping Image 4574f80c91e4 already pushed, skipping Image 37c2cc34fa4e already pushed, skipping 757db77867dd: Image successfully pushed Pushing tag for rev [757db77867dd] on {https:// registry-1.docker.io/v1/repositories/mehdi/nodejs/tags/ latest} Any idea why these images are skipped?
- 16. Container vs. Image! Still Puzzled? Running container from an image: Creating image from a container: $ docker ps -a! $ docker commit -m “Image description" <CONTAINER_ID> <USERNAME>/<REPO> $ docker run -i -t ubuntu:12.04 /bin/bash Lets see a Demo
- 18. Demo Deploying a sample app on the cloud using Docker
- 19. Your Next Weekend Fun Project: Deploy something with Dokku Dokku Docker powered mini-Heroku in around 100 lines of Bash See the demo here: http://vimeo.com/68631325 https://github.com/progrium/dokku
- 20. The rabbit hole goes deeper than that… • How to deal with data, logs, file uploads? Where to store? Inside container? Inside host? Inside another container? Hint: Read http://docs.docker.io/en/latest/use/ working_with_volumes/ • How to deal with distributed systems? Hint: Follow http://www.centurylinklabs.com/category/ docker-posts/
- 21. Keep following… • https://coreos.com/ • http://www.confd.io/ • http://www.serfdom.io/ • http://www.dockerbook.com/ (Not yet released)* * As of May, 2014
- 22. Docker cheat sheet • https://gist.github.com/wsargent/7049221 • https://coderwall.com/p/2es5jw
- 23. Questions?