Build from Dockerfile
Build an image from the Dockerfile in the current directory.
bashANYdockerfilebuild
bash
docker build -t myapp:dev .Notes
By default Docker reads `./Dockerfile` and sends the current directory as build context.
Dockerfile Cheat Sheet
High-value Dockerfile instructions, patterns, and build flags for reproducible and efficient image builds.
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Dockerfile Basics
Core build invocation and essential Dockerfile instructions.
bash
docker build -f Dockerfile.prod -t myapp:prod .Notes
Common for environment-specific builds.
Use FROM instruction
Set the base image for a Dockerfile stage.
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dockerfile
FROM node:20-alpineNotes
Every stage starts from a `FROM` instruction.
Use WORKDIR instruction
Set the working directory for subsequent instructions.
dockerfileANYdockerfileinstruction
dockerfile
WORKDIR /appNotes
Avoid repetitive `cd` logic and make paths explicit.
Copy files into image
Copy files from the build context into the image.
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dockerfile
COPY package*.json ./Notes
Use `.dockerignore` to keep build contexts lean.
dockerfile
RUN npm ciNotes
Common for dependency installation and image preparation.
Set default command
Set the default command when the container starts.
dockerfileANYdockerfileinstructionruntime
dockerfile
CMD ["node", "server.js"]Notes
Can be overridden at runtime.
dockerfile
ENTRYPOINT ["/usr/local/bin/app"]Notes
Often paired with `CMD` for default arguments.
Document a listening port
Document the port the application listens on.
dockerfileANYdockerfileinstructionnetwork
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EXPOSE 3000Notes
This does not publish ports by itself.
Set environment variable
Set environment variables in the image.
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ENV NODE_ENV=productionNotes
Values become defaults at runtime unless overridden.
dockerfile
ARG NODE_VERSION=20Notes
Build args are available only during build unless copied into `ENV`.
Set image metadata label
Attach metadata labels to the image.
dockerfileANYdockerfileinstructionlabels
dockerfile
LABEL org.opencontainers.image.source="https://github.com/acme/myapp"Notes
Useful for provenance, ownership, and automation.
Common Patterns
Repeatable Dockerfile patterns for efficient, secure images.
Use multi-stage build
Build artifacts in one stage and copy only runtime output into the final stage.
dockerfileANYdockerfilemultistagepatterns
dockerfile
FROM node:20-alpine AS build
WORKDIR /app
COPY package*.json ./
RUN npm ci
COPY . .
RUN npm run build
FROM nginx:alpine
COPY /app/dist /usr/share/nginx/htmlNotes
Multi-stage builds keep runtime images smaller and cleaner.
dockerfile
RUN addgroup -S app && adduser -S app -G app
USER appNotes
A common hardening practice for production images.
Add health check
Define a health check command for the container.
dockerfileANYdockerfilehealthcheckpatterns
dockerfile
HEALTHCHECK CMD wget -qO- http://localhost:3000/health || exit 1Notes
Useful with orchestrators and compose health status.
dockerfile
COPY . /appNotes
Avoids extra `chown` layers in many images.
Cache dependencies effectively
Copy dependency manifests before application code to maximize layer cache reuse.
dockerfileANYdockerfilecachepatterns
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COPY package*.json ./
RUN npm ci
COPY . .Notes
A classic Dockerfile optimization for JS apps.
Use .dockerignore
Exclude unnecessary files from build context.
gitignoreANYdockerfiledockerignorepatterns
gitignore
node_modules
dist
.git
.env
coverageNotes
Reducing context size speeds up builds and avoids leaking sensitive files.
Build Flags and Targets
Common build options used with Dockerfiles.
bash
docker build --target build -t myapp:build .Notes
Useful for debugging or exporting builder-only images.
bash
docker build --build-arg NODE_VERSION=20 -t myapp:dev .Notes
Great for version pinning and parameterized builds.
bash
docker build --no-cache -t myapp:clean .Notes
Useful when cache corruption or stale dependencies are suspected.
Always pull newer base image
Attempt to pull a newer base image before build.
bashANYdockerfilebuildbase-image
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docker build --pull -t myapp:dev .Notes
Good for CI pipelines that want refreshed base layers.
Build for specific platform
Build for a target platform when supported.
bashANYdockerfilebuildplatform
bash
docker build --platform linux/amd64 -t myapp:amd64 .Notes
Often used together with Buildx or multi-platform workflows.
bash
docker build --progress=plain -t myapp:dev .Notes
Helpful when debugging failing builds in CI.
More in Docker
Docker Swarm Cheat Sheet
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Docker Buildx Cheat Sheet
Modern BuildKit and Buildx reference for multi-platform builds, cache, secrets, and remote outputs.
Docker Cheat Sheet
Comprehensive Docker Engine CLI reference for images, containers, networks, volumes, registries, contexts, and cleanup.
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