Introduction to Docker
What is Docker?
An open platform for distributed applications
It's based on Linux containers
A configurable Lightweight and Fast Virtual Machine Like environment
Linux Containers
Allows you to pack an application along with its stack
Abstract application from the guest OS
Prevents dependency hell
Big companies use containers to deploy applications many time a day
Why are containers popular now?
Docker makes it easy for everyone to work with containers
Provides a simple workflow around containers
Docker in detail
Docker separates applications from infrastructure using container technology
Similar to how Virtual Machines separates OS from the hardware it runs in
Docker vs VM
Benefits of Docker
Run apps locally in two steps
Easy to setup
Have a consistent environment across different machines
Consistency
Docker apps can be run anywhere, on any machine
Portable
Docker components
Docker daemon
Docker CLI
Workflow
From: https://speakerdeck.com/asm89/docker
Usual setup
Now
FROM ruby:2.3.1
RUN apt-get update
RUN apt-get install nodejs
RUN mkdir /myapp
WORKDIR /myapp
ADD Gemfile /myapp/Gemfile
ADD Gemfile.lock /myapp/Gemfile.lock# FROM: Get image from docker index
# RUN: Run commands inside container
Dockerfile
db:
image: postgres:9.5.0
volumes:
- .:/tmp/data/
web:
build: .
command: bundle exec rails s -p 3000 -b '0.0.0.0'
volumes:
- .:/code
ports:
- "3000:3000"
links:
- db# Rails server
# Share this folder
# Get Postgres image
docker-compose.yml
# Build project
docker-compose build
Docker commands
# Run project
docker-compose up
Docker hub
Demo
https://30k.co/1of
What's Docker
By pablovallejo
What's Docker
Introduction to Docker
