Dockerfile Generator - Build Docker Images

Generate optimized Dockerfiles for Node.js, Python, Go, and static sites. Multi-stage builds, security best practices, and production-ready configs.

Project Type

Node.js Version

Application Port

Entry Point / Command

Options

Multi-stage build

Non-root user

Health check

OCI labels

Dockerfile

.dockerignore

node_modules
npm-debug.log
.git
.gitignore
.env
.env.*
Dockerfile
.dockerignore
README.md
.github
coverage
.nyc_output
*.log

Build & Run

# Build image
docker build -t myapp .

# Run container
docker run -p 3000:3000 myapp

# Run with env file
docker run --env-file .env -p 3000:3000 myapp

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Frequently Asked Questions

A Dockerfile is a text file with instructions to build a Docker image. Each instruction creates a layer. Docker executes them in order to create a reproducible container image.

Multi-stage builds use multiple FROM statements. Build in one stage (with compilers, dev tools), copy only artifacts to final stage. Results in smaller, secure images.

Alpine Linux is ~5MB vs ~100MB+ for Ubuntu/Debian. Smaller images mean faster pulls, less storage, reduced attack surface. Use -alpine tags when available.

.dockerignore excludes files from build context (like .gitignore). Exclude node_modules, .git, logs, etc. Speeds up builds and reduces image size.

Running as root in containers is a security risk. If an attacker escapes the container, they have root on the host. Create a non-root user with USER instruction.

COPY just copies files. ADD can extract tars and fetch URLs. Prefer COPY for clarity unless you need ADD's features. COPY is more predictable.

Use multi-stage builds, Alpine base images, combine RUN commands, remove cache after install, use .dockerignore, don't install unnecessary packages.

ENTRYPOINT is the main executable, CMD provides default arguments. ENTRYPOINT ["node"] CMD ["app.js"] lets users override args but keeps node as entrypoint.

Never bake secrets into images. Use environment variables, Docker secrets, or mount secrets at runtime. ARG values appear in image history.

Order instructions by change frequency. COPY package.json before code so npm install is cached. Changes invalidate that layer and all following layers.

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