Building Containerized Applications with Docker

A high-level introduction to containers, Docker, and how you might use them within an application. Video here: https://www.youtube.com/watch?v=SGyLjrY3LJo

Transcript

1. Building Containerized Applications with Docker Laura Frank rheinwein @rhein_wein
2. Containerization: what is it? Using containers in your project Docker basics
4. Docker != containers
5. A tool for managing containers • Managing code to run inside • Executing and running code Docker
6. • Run in a self-contained execution environment • Share the kernel of host system • Are isolated from other containers • Have fast boot times & low overhead Containers
7. A container is a virtualization layer — sort of like a VM — but with some fundamental differences If you deploy your applications in virtual machines, you can instead deploy them in containers.
8. hardware host OS hypervisor $ guest OS libraries web $ guest OS $ guest OS libraries DB libraries web
9. hardware host OS libraries web libraries DB libraries web
10. hardware host OS container runtime engine libraries libraries web web DB
11. Containers have slightly more complexity but They reduce the amount of time/space resources needed to run your application
12. • It’s fast! • It’s cheap! • It’s portable! • It’s safe! Benefits of Containerization
13. Docker Basics
14. A tool for managing containers • Managing code to run inside • Executing and running code Docker
15. Engine Hub docker.com
16. registry.hub.docker.com
17. Interacting with the Registry • Push and pull —just like GitHub • Two types of images • Services • Project base images
18. Private Registries • Get image from Docker Registry • Can have authentication • Push and pull just like with Docker Hub
19. A tool for managing containers • Managing code to run inside • Executing and running code Docker
20. hardware host OS container runtime engine libraries libraries app 1 app 1 app 2
21. • docker run my_image • docker pull your_image • docker images • docker ps Docker CLI
22. Using Containers in Your Application
23. • A computer • Application code • Coffee (if you’d like) Things you need Installing Docker
24. Anything else? You need to use a lightweight VM. Pro Tip: Boot2Docker (OSX and Windows) Linux? Install Docker with official packages. A Computer
25. To run your application in a container, you must first create an image Application Code All containers are based on images An image is controlled by a Dockerfile
26. Application Code Two ways to get images: docker pull foo/bar or docker run foo/bar 1. Pull down from Docker Hub docker build -t foo/bar . 2. Build from your own Dockerfile
27. • Available on Docker Hub • Maintained by other people (laziness++) • Repositories includes instructions for bootstrapping • Images can be base images or actually run services Application Code: Official Images
28. Application Code • Static: all files and code are contained in image • Dynamic: link folders to modify code (development only)
29. Application Code • Static: all files and code are contained in image • Dynamic: link folders to modify code (development only)
30. Application Code Using static images from the Docker Hub, you can create a containerized application without having to write your own code docker run mysql (…) docker run wordpress (…)
31. Application Code You can also package your own code and run it. docker run mysql (…) docker run my_image (…) docker build -t my_image .
32. FROM centurylink/ruby-base:2.1.2 MAINTAINER Laura Frank <ljfrank@gmail.com> EXPOSE 4567 RUN mkdir -p /usr/src/app ADD . /usr/src/app WORKDIR /usr/src/app RUN bundle install CMD “ruby hello_world.rb" Dockerfile
33. FROM centurylink/ruby-base:2.1.2 MAINTAINER Laura Frank <ljfrank@gmail.com> EXPOSE 4567 RUN mkdir -p /usr/src/app ADD . /usr/src/app WORKDIR /usr/src/app RUN bundle install CMD “ruby hello_world.rb" Dockerfile
34. FROM centurylink/ruby-base:2.1.2 MAINTAINER Laura Frank <ljfrank@gmail.com> EXPOSE 4567 RUN mkdir -p /usr/src/app ADD . /usr/src/app WORKDIR /usr/src/app RUN bundle install CMD “ruby hello_world.rb" Dockerfile This copies code into the container STATIC! Not for apps under active development Great for dependencies and production applications
35. FROM centurylink/ruby-base:2.1.2 MAINTAINER Laura Frank <ljfrank@gmail.com> EXPOSE 4567 RUN mkdir -p /usr/src/app ADD . /usr/src/app WORKDIR /usr/src/app RUN bundle install CMD “ruby hello_world.rb" Dockerfile This makes things happen to your code
36. FROM centurylink/ruby-base:2.1.2 MAINTAINER Laura Frank <ljfrank@gmail.com> EXPOSE 4567 RUN mkdir -p /usr/src/app ADD . /usr/src/app WORKDIR /usr/src/app RUN bundle install CMD “ruby hello_world.rb" Dockerfile This makes the code happen
37. But this seems like a lot of tedious work, and I am very lazy.
38. Application Templating • Use your own images, or images from the Docker Registry • Specify config options beforehand • Run applications with one or two simple commands
39. Text-only templating tool fig.sh Dump requirements into fig.yml and run with fig up Fig aka Docker Compose
40. Templating language similar to Fig/Docker Compose Supports remote deployments panamax.io/get-panamax
41. --- name: Rails with PostgreSQL description: Rails with PostgreSQL images: - category: Web Tier name: Rails source: rheinwein/rails:latest description: Rails App type: Default expose: [] ports: - host_port: '8080' container_port: '3000' links: - service: Database alias: DB_1 environment: [] volumes: []
42. –Johnny Appleseed “Type a quote here.”
43. Docker Hub: registry.hub.docker.com Boot2Docker: boot2docker.io Panamax: panamax.io Rails Girls Summer of Code!: railsgirlssummerofcode.org rheinwein/hello-world-container-demo
44. Thanks! Laura Frank rheinwein @rhein_wein