Show List
Tutorials > Docker > Docker Coding Questions

Docker Coding Questions


  • Create a Dockerfile for a Python web application that runs on port 8080 and uses Flask as the web framework. Answer:
sql
Copy code
FROM python:3.8-slim-buster

WORKDIR /app

COPY requirements.txt .
RUN pip install --no-cache-dir -r requirements.txt

COPY . .

EXPOSE 8080

CMD ["python", "app.py"]
  • Create a Docker Compose file that sets up a WordPress site with a MySQL database. Answer:
yaml
Copy code
version: "3"

services:
  db:
    image: mysql:5.7
    volumes:
      - db_data:/var/lib/mysql
    restart: always
    environment:
      MYSQL_ROOT_PASSWORD: example_password
      MYSQL_DATABASE: wordpress
      MYSQL_USER: wordpress
      MYSQL_PASSWORD: example_password

  wordpress:
    depends_on:
      - db
    image: wordpress:latest
    ports:
      - "8000:80"
    restart: always
    environment:
      WORDPRESS_DB_HOST: db
      WORDPRESS_DB_USER: wordpress
      WORDPRESS_DB_PASSWORD: example_password
      WORDPRESS_DB_NAME: wordpress

volumes:
  db_data:
  • Write a Dockerfile for a Java application that uses Gradle to build the application. Answer:
bash
Copy code
FROM gradle:6.9.0-jdk11 AS builder

WORKDIR /app

COPY build.gradle settings.gradle gradlew ./
COPY gradle ./gradle
RUN ./gradlew build -x test --no-daemon

COPY src ./src
RUN ./gradlew build -x test --no-daemon

FROM openjdk:11.0.11-jre-slim-buster

WORKDIR /app

COPY --from=builder /app/build/libs/*.jar ./app.jar

EXPOSE 8080

CMD ["java", "-jar", "app.jar"]
  • Create a Dockerfile for a Node.js application that uses Yarn to install dependencies. Answer:
sql
Copy code
FROM node:14.17.4-alpine3.14

WORKDIR /app

COPY package.json yarn.lock ./

RUN yarn install --frozen-lockfile

COPY . .

EXPOSE 3000

CMD ["yarn", "start"]


  • Create a Docker Compose file for a multi-container application that includes a web server and a database. Answer:
yaml
Copy code
version: "3"

services:
  web:
    build: .
    ports:
      - "8000:8000"
    depends_on:
      - db
    environment:
      DATABASE_URL: postgresql://user:password@db:5432/dbname

  db:
    image: postgres:12
    volumes:
      - db_data:/var/lib/postgresql/data
    environment:
      POSTGRES_USER: user
      POSTGRES_PASSWORD: password
      POSTGRES_DB: dbname

volumes:
  db_data:
  • Write a Dockerfile for a Go application that compiles the binary during the build process. Answer:
sql
Copy code
FROM golang:1.17.2-alpine AS builder

WORKDIR /app

COPY . .

RUN go build -o app .

FROM alpine:3.14

WORKDIR /app

COPY --from=builder /app/app .

EXPOSE 8080

CMD ["./app"]
  • Create a Dockerfile for a Ruby on Rails application that uses PostgreSQL as the database. Answer:
sql
Copy code
FROM ruby:3.0.2-alpine

WORKDIR /app

COPY Gemfile Gemfile.lock ./
RUN bundle install

COPY . .

RUN apk add --no-cache postgresql-dev && \
    bundle exec rake assets:precompile

EXPOSE 3000

CMD ["rails", "server", "-b", "0.0.0.0"]
  • Write a Dockerfile for a .NET Core application that uses the SDK image to build the application. Answer:
sql
Copy code
FROM mcr.microsoft.com/dotnet/sdk:5.0 AS builder

WORKDIR /app

COPY . .

RUN dotnet publish -c Release -o out

FROM mcr.microsoft.com/dotnet/aspnet:5.0-alpine3.14

WORKDIR /app

COPY --from=builder /app/out .

EXPOSE 80

CMD ["dotnet", "app.dll"]


  • Write a Dockerfile for a Python Flask application that uses the Alpine Linux base image. Answer:
sql
Copy code
FROM python:3.9.7-alpine

WORKDIR /app

COPY requirements.txt .

RUN apk add --no-cache gcc musl-dev libffi-dev openssl-dev && \
    pip install -r requirements.txt

COPY . .

ENV FLASK_APP=app.py

EXPOSE 5000

CMD ["flask", "run", "--host", "0.0.0.0"]
  • Create a Docker Compose file for a multi-container application that includes a web server, a database, and a worker. Answer:
yaml
Copy code
version: "3"

services:
  web:
    build: .
    ports:
      - "8000:8000"
    depends_on:
      - db
      - worker
    environment:
      DATABASE_URL: postgresql://user:password@db:5432/dbname
      REDIS_URL: redis://cache:6379

  db:
    image: postgres:12
    volumes:
      - db_data:/var/lib/postgresql/data
    environment:
      POSTGRES_USER: user
      POSTGRES_PASSWORD: password
      POSTGRES_DB: dbname

  cache:
    image: redis:6

  worker:
    build: worker
    depends_on:
      - db
      - cache
    environment:
      DATABASE_URL: postgresql://user:password@db:5432/dbname
      REDIS_URL: redis://cache:6379

volumes:
  db_data:
  • Write a Dockerfile for a Node.js application that uses the official Node.js base image. Answer:
sql
Copy code
FROM node:16.13.0-alpine3.14

WORKDIR /app

COPY package.json package-lock.json ./

RUN npm install

COPY . .

EXPOSE 3000

CMD ["npm", "start"]
  • Create a Docker Compose file for a multi-container application that includes a web server, a database, and a message broker. Answer:
yaml
Copy code
version: "3"

services:
  web:
    build: .
    ports:
      - "8000:8000"
    depends_on:
      - db
      - broker
    environment:
      DATABASE_URL: postgresql://user:password@db:5432/dbname
      BROKER_URL: amqp://user:password@broker:5672/

  db:
    image: postgres:12
    volumes:
      - db_data:/var/lib/postgresql/data
    environment:
      POSTGRES_USER: user
      POSTGRES_PASSWORD: password
      POSTGRES_DB: dbname

  broker:
    image: rabbitmq:3.9-alpine
    environment:
      RABBITMQ_DEFAULT_USER: user
      RABBITMQ_DEFAULT_PASS: password

volumes:
  db_data:


  • Write a Dockerfile for a Ruby on Rails application that uses the Alpine Linux base image. Answer:
sql
Copy code
FROM ruby:3.1.0-alpine3.14

WORKDIR /app

COPY Gemfile Gemfile.lock ./

RUN apk add --no-cache build-base postgresql-dev tzdata && \
    bundle install --jobs 4

COPY . .

ENV RAILS_ENV=production
ENV RAILS_SERVE_STATIC_FILES=true
ENV RAILS_LOG_TO_STDOUT=true
ENV RAILS_MAX_THREADS=5

EXPOSE 3000

CMD ["bundle", "exec", "rails", "server", "-b", "0.0.0.0"]
  • Create a Docker Compose file for a multi-container application that includes a web server, a database, and a Redis cache. Answer:
yaml
Copy code
version: "3"

services:
  web:
    build: .
    ports:
      - "8000:8000"
    depends_on:
      - db
      - cache
    environment:
      DATABASE_URL: postgresql://user:password@db:5432/dbname
      REDIS_URL: redis://cache:6379

  db:
    image: postgres:12
    volumes:
      - db_data:/var/lib/postgresql/data
    environment:
      POSTGRES_USER: user
      POSTGRES_PASSWORD: password
      POSTGRES_DB: dbname

  cache:
    image: redis:6

volumes:
  db_data:
  • Write a Dockerfile for a PHP application that uses the Apache web server. Answer:
less
Copy code
FROM php:8.1.0-apache

WORKDIR /var/www/html

COPY . .

RUN docker-php-ext-install pdo_mysql

EXPOSE 80

CMD ["apache2-foreground"]
  • Create a Docker Compose file for a multi-container application that includes a web server, a database, and a background worker. Answer:
yaml
Copy code
version: "3"

services:
  web:
    build: .
    ports:
      - "8000:8000"
    depends_on:
      - db
      - worker
    environment:
      DATABASE_URL: postgresql://user:password@db:5432/dbname
      WORKER_URL: amqp://user:password@worker:5672/

  db:
    image: postgres:12
    volumes:
      - db_data:/var/lib/postgresql/data
    environment:
      POSTGRES_USER: user
      POSTGRES_PASSWORD: password
      POSTGRES_DB: dbname

  worker:
    build: worker
    depends_on:
      - db
      - broker
    environment:
      DATABASE_URL: postgresql://user:password@db:5432/dbname
      BROKER_URL: amqp://user:password@broker:5672/

volumes:
  db_data:
    Leave a Comment

  • captcha text