Docker: What It Is and Why You Should Care

Transcript

1. Docker What It Is and Why You Should Care

2. My Story

3. What is Docker? Virtualization

4. None
5. None

6. = Virtual Machines Guest Host

7. = Docker Containers

8. That’s all great. Why should I care?

9. • Install Homebrew • brew install several packages - SQL,

   Imagemagick • Install RVM or Rbenv • Install one or more versions of Ruby • Clone one or more Git repos • Run bundle/npm/bower/etc install for each repo

10. • Start the db server (unless it’s always running) •

    Start the rails app • Background workers? Sidekiq and Redis • SoA? Need to start those up too on the right port • iTerm or Tmux setup to run all this? Foreman? • Foreman requires same directory. Subcontractor.
11. None

12. • Install Docker • Clone your Git repos • Place

    your docker-compose.yml file

13. • docker-compose up

14. = Dev Dev

15. = Dev CI

16. ≈ Dev Prod

17. Where do I start?

18. Background: Building Blocks

19. Background Tools

20. • Dockerfile • docker-compose.yml

21. Docker Engine - Dockerfile

22. FROM ruby:2.3.1-slim RUN apt-get update -qq && apt-get install -y

    \ build-essential libpq-dev postgresql-client ENV RAILS_ROOT /var/www/myapp RUN mkdir -p $RAILS_ROOT/tmp/pids WORKDIR $RAILS_ROOT COPY Gemfile Gemfile COPY Gemfile.lock Gemfile.lock RUN gem install bundler RUN bundle install

23. Docker Compose YAML

24. app: build: . command: rails server --port 3000 --binding 0.0.0.0

    environment: RAILS_ENV: development DATABASE_HOST: db links: - db ports: - 3000:3000 volumes: - .:/var/www/myapp db: image: postgres:9.5.3 environment: POSTGRES_USER: username POSTGRES_PASSWORD: password volumes: - myapp-db:/var/lib/postgresql/data

25. sidekiq: build: . command: bundle exec sidekiq environment: REDIS_URL: redis://redis:6379

    links: - db - redis volumes: - .:/var/www/myapp redis: image: redis

26. Dockerfile docker-compose.yml

27. Other Ways To Get Started

28. None

29. Takeaways • Docker reduces dev dependencies • It adds parity

    where it is used (Dev-CI-Production) • Easy to get started

30. Questions?

31. • Alexander Clark • Twitter @atheclark • Blog http://alexander-clark.com/blog •

    Github alexander-clark • Slack alexander-clark

32. Thanks for listening.