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Docker Cheatsheet

Dockerfile, CLI commands, docker-compose, volumes, and networks

Dockerfile — Core Instructions

FROM golang:1.23-alpine AS builder
WORKDIR /app
COPY go.mod go.sum ./
RUN go mod download
COPY . .
RUN go build -o server .

FROM alpine:3.19
RUN adduser -D appuser
USER appuser
COPY --from=builder /app/server /server
EXPOSE 8080
CMD ["/server"]

Dockerfile — Common Instructions

FROM image:tag         # base image
WORKDIR /app          # set working directory
COPY src dest         # copy files from host
ADD src dest          # like COPY but also handles URLs & .tar
RUN command           # run during build
CMD ["cmd", "arg"]    # default command (can be overridden)
ENTRYPOINT ["cmd"]    # fixed executable
ENV KEY=value         # set environment variable
ARG NAME=default      # build-time variable
EXPOSE 8080           # document port (does not publish)
VOLUME ["/data"]      # create mount point
LABEL key="value"     # metadata

Container Lifecycle

docker run -d -p 8080:8080 --name api myimage   # run detached
docker run -it ubuntu bash                       # interactive shell
docker run --rm myimage                          # remove after exit
docker start/stop/restart container_name
docker pause/unpause container_name
docker rm container_name                         # remove stopped
docker rm -f container_name                     # force remove running
docker ps                                       # list running
docker ps -a                                    # list all

Images

docker build -t myapp:1.0 .              # build
docker build --no-cache -t myapp .       # build without cache
docker build --target builder -t myapp . # multi-stage: specific stage
docker images                            # list images
docker rmi image_id                      # remove image
docker pull nginx:alpine                 # pull from registry
docker push registry/myapp:tag           # push to registry
docker tag myapp registry/myapp:latest   # tag image
docker inspect image_id                  # full metadata

Logs & Debugging

docker logs container_name              # view logs
docker logs -f container_name           # follow (tail -f)
docker logs --tail 100 container_name   # last 100 lines
docker exec -it container_name bash     # shell into running container
docker exec container_name env          # run command in container
docker cp container:/path/file .        # copy file from container
docker stats                            # live resource usage
docker inspect container_name          # full details

Volumes & Networks

# Volumes
docker volume create mydata
docker volume ls
docker volume rm mydata
docker run -v mydata:/app/data myimage  # named volume
docker run -v $(pwd):/app myimage       # bind mount

# Networks
docker network create mynet
docker network ls
docker run --network mynet myimage
docker network connect mynet container_name
docker network inspect mynet

docker-compose

# docker-compose.yml
version: '3.9'
services:
  api:
    build: .
    ports: ["8080:8080"]
    environment:
      - DB_URL=postgres://user:pass@db:5432/mydb
    depends_on: [db]
    volumes: ["./config:/app/config"]

  db:
    image: postgres:16-alpine
    environment:
      POSTGRES_DB: mydb
      POSTGRES_USER: user
      POSTGRES_PASSWORD: pass
    volumes: ["pgdata:/var/lib/postgresql/data"]

volumes:
  pgdata:

docker-compose Commands

docker compose up -d          # start in background
docker compose up --build     # rebuild and start
docker compose down           # stop and remove containers
docker compose down -v        # also remove volumes
docker compose logs -f api    # follow service logs
docker compose exec api bash  # shell into service
docker compose ps             # list service status
docker compose restart api    # restart one service
docker compose pull           # pull latest images

Cleanup

docker system prune           # remove all stopped containers, unused images
docker system prune -a        # also remove unused images (not just dangling)
docker container prune        # remove stopped containers
docker image prune            # remove dangling images
docker volume prune           # remove unused volumes
docker network prune          # remove unused networks

Loading…

FROM golang:1.23-alpine AS builder WORKDIR /app COPY go.mod go.sum ./ RUN go mod download COPY . . RUN go build -o server . FROM alpine:3.19 RUN adduser -D appuser USER appuser COPY --from=builder /app/server /server EXPOSE 8080 CMD ["/server"]

Dockerfile — Common Instructions

FROM image:tag # base image WORKDIR /app # set working directory COPY src dest # copy files from host ADD src dest # like COPY but also handles URLs & .tar RUN command # run during build CMD ["cmd", "arg"] # default command (can be overridden) ENTRYPOINT ["cmd"] # fixed executable ENV KEY=value # set environment variable ARG NAME=default # build-time variable EXPOSE 8080 # document port (does not publish) VOLUME ["/data"] # create mount point LABEL key="value" # metadata

Container Lifecycle

docker run -d -p 8080:8080 --name api myimage # run detached docker run -it ubuntu bash # interactive shell docker run --rm myimage # remove after exit docker start/stop/restart container_name docker pause/unpause container_name docker rm container_name # remove stopped docker rm -f container_name # force remove running docker ps # list running docker ps -a # list all

Images

docker build -t myapp:1.0 . # build docker build --no-cache -t myapp . # build without cache docker build --target builder -t myapp . # multi-stage: specific stage docker images # list images docker rmi image_id # remove image docker pull nginx:alpine # pull from registry docker push registry/myapp:tag # push to registry docker tag myapp registry/myapp:latest # tag image docker inspect image_id # full metadata

Logs & Debugging

docker logs container_name # view logs docker logs -f container_name # follow (tail -f) docker logs --tail 100 container_name # last 100 lines docker exec -it container_name bash # shell into running container docker exec container_name env # run command in container docker cp container:/path/file . # copy file from container docker stats # live resource usage docker inspect container_name # full details

Volumes & Networks

# Volumes docker volume create mydata docker volume ls docker volume rm mydata docker run -v mydata:/app/data myimage # named volume docker run -v $(pwd):/app myimage # bind mount # Networks docker network create mynet docker network ls docker run --network mynet myimage docker network connect mynet container_name docker network inspect mynet

docker-compose

# docker-compose.yml version: '3.9' services: api: build: . ports: ["8080:8080"] environment: - DB_URL=postgres://user:pass@db:5432/mydb depends_on: [db] volumes: ["./config:/app/config"] db: image: postgres:16-alpine environment: POSTGRES_DB: mydb POSTGRES_USER: user POSTGRES_PASSWORD: pass volumes: ["pgdata:/var/lib/postgresql/data"] volumes: pgdata:

docker-compose Commands

docker compose up -d # start in background docker compose up --build # rebuild and start docker compose down # stop and remove containers docker compose down -v # also remove volumes docker compose logs -f api # follow service logs docker compose exec api bash # shell into service docker compose ps # list service status docker compose restart api # restart one service docker compose pull # pull latest images

Cleanup

docker system prune # remove all stopped containers, unused images docker system prune -a # also remove unused images (not just dangling) docker container prune # remove stopped containers docker image prune # remove dangling images docker volume prune # remove unused volumes docker network prune # remove unused networks