Docker

command

• CMD
  • container시작시 수행 명령
  • docker file당 1개
  • 시작시 override 가능
• ENTRYPOINT
  • container시작시
  • override불가 . 즉 변경없이 무조건 실행되어야 할 내용.
  • run image arg 로 argument받을수 있음
• CMD vs ENTRYPOINT
  • runtime에 override될 default argument가 있다면 CMD 좋음
  • excutable을 실행하거나, 매번 변경없이 실행하고자 하면 ENTRYPOINT가 좋음
• WORKDIR
  • cd와 같음
• COPY/ADD
  • ADD는 tar를 풀어서 올림

유용한 cli command

• Containers
  • Use docker container my_command

  create — Create a container from an image. 
  start — Start an existing container. 
  run — Create a new container and start it. 
  ls — List running containers. 
  inspect — See lots of info about a container.
  logs — Print logs. 
  stop — Gracefully stop running container. 
  kill —Stop main process in container abruptly. 
  rm— Delete a stopped container.
  

• Images
  • Use docker image my_command

  build — Build an image.
  push — Push an image to a remote registry.
  ls — List images. 
  history — See intermediate image info.
  inspect — See lots of info about an image, including the layers. 
  rm — Delete an image.
  

• Misc

  docker version — List info about your Docker Client and Server versions.
  docker login — Log in to a Docker registry.
  docker system prune — Delete all unused containers, unused networks, and dangling images.
  

tip

• image size
  • docker image ls

multistage

• 이전 stage의 결과만 재사용
  • COPY --from=

FROM golang:1.7.3 AS build
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 -installsuffix cgo -o app .

FROM alpine:latest  
RUN apk --no-cache add ca-certificates
WORKDIR /root/
COPY --from=build /go/src/github.com/alexellis/href-counter/app .
CMD ["./app"]

image 사이즈 줄이기

• 되도록 RUN에서 여러 command 실행. 각 run마다 layer가 생성되기 때문

RUN apt-get update && apt-get install -y \
    package-one \
    package-two 
 && rm -rf /var/lib/apt/lists/*

copy 파일

• https://stackoverflow.com/questions/22907231/copying-files-from-host-to-docker-container

docker cp foo.txt mycontainer:/foo.txt
docker cp mycontainer:/foo.txt .