Images

• Build

  docker build -t img_x .

  • By using . it will look for Dockerfile in the pwd, override this by specifying your own Dockerfile

• Remove

  docker image rm img_x

• List

  docker image ls

Define Dockerfile

• Extend alpine image

  FROM alpine
  
  RUN apk add --update --no-cache -q \
      bash \
      curl

• Extend debian image

  FROM debian
  
  RUN apt-get update && apt-get install -y \
      bash \
      curl

• Multi-stage builds

  1. Use tooling to build an artifact

  2. Copy that artifact into a minimal runtime

     FROM golang:1.7.3
     WORKDIR /go/src/github.com/alexellis/href-counter/
     RUN go get -d -v golang.org/x/net/html  
     COPY app.go .
     RUN CGO_ENABLED=0 GOOS=linux go build -a -installsuffimg_x cgo -o app .
     
     FROM alpine:latest  
     RUN apk --no-cache add ca-certificates
     WORKDIR /root/
     COPY --from=0 /go/src/github.com/alexellis/href-counter/app .
     CMD ["./app"]

Containers

• Run

  docker run -d --name cntr_x tag img_x

• Execute

  docker run img_x echo "hello world!"
  
  # interactive session for debugging
  docker run -it img_x /bin/bash

• List

  docker ps

• Logs

  docker logs -f cntr_x

• Remove

  docker rm -f cntr_x

docker-compose

A useful tool for defining how to build and orchestrate multiple containers.

• Build

  # all
  docker-compose build
  
  # single service
  docker-compose build svc_x

• Run

  # all
  docker-compose up -d
  
  # single service
  docker-compose run svc_x

• Stop

  docker-compose down
  
  # remove volumes (e.g. wipe database)
  docker-compose down --volumes

• Execute

  docker-compose run svc_x echo "hello world!"
  
  # interactive session for debugging
  docker-compose run -it svc_x /bin/bash

• Logs

  # all
  docker-compose logs -f
  
  # single service
  docker-compose logs -f svc_x

• Run commands against compose file with different name

  docker-compose run -f ../../pew.yml

Define docker-compose.yml

• Build from Dockerfile

  version: '3'
  services:
  svc_x:
      build:
      context: .
      dockerfile: svc_x.Dockerfile

• Dependent containers

  version: '3'
  services:
  pg:
      image: postgres:12-alpine
      environment:
          POSTGRES_PASSWORD: postgres
      networks: 
          - integration
  pg_migration:
      image: flyway/flyway
      command: -url=jdbc:postgresql://pg:5432/postgres -user=postgres -password=postgres -connectRetries=60 migrate
      volumes:
          - ./flyway/sql:/flyway/sql
      networks: 
          - integration
      depends_on:
          - pg