UI はローカライズ済みです。スキルの紹介と説明文書は選択した言語へ AI が自動翻訳し、コード・コマンド・パス・専門用語は原文のままです。原作者の文書が優先されます。
スキルを探す
運用・デプロイ · SKILL.md

create-multistage-dockerfile

create-multistage-dockerfile

Create multi-stage Dockerfiles that separate build and runtime environments for minimal production images. Covers builder/runtime stage separation, artifact copying, scratch/distroless/alpine targets, and size comparison. Use when production images are too large, when build tools are included in the final image, when you need separate dev and prod images fr…

Independent GitHub snapshot · Automated classification · Original documentation governs

スキルの説明

GitHub

name: create-multistage-dockerfile locale: caveman source_locale: en source_commit: 82c77053 fence_basis_commit: 82c77053 translator: "Julius Brussee homage — caveman" translation_date: "2026-04-19" description: > Create multi-stage Dockerfiles that separate build and runtime environments for minimal production images. Covers builder/runtime stage separation, artifact copying, scratch/distroless/alpine targets, and size comparison. Use when production images are too large, when build tools are included in the final image, when you need separate dev and prod images from one Dockerfile, or when deploying to constrained environments like edge or serverless. license: MIT allowed-tools: Read Write Edit Bash Grep Glob metadata: author: Philipp Thoss version: "1.0" domain: containerization complexity: intermediate language: Docker tags: docker, multi-stage, distroless, alpine, scratch, optimization

Create Multi-Stage Dockerfile

Build multi-stage Dockerfiles producing minimal production images. Separate build tooling from runtime.

When Use

  • Production images too large (>500MB for compiled languages)
  • Build tools (compilers, dev headers) in final image
  • Need separate images for dev and prod from one Dockerfile
  • Deploying to constrained environments (edge, serverless)

Inputs

  • Required: Existing Dockerfile or project to containerize
  • Required: Language and build system (npm, pip, go build, cargo, maven)
  • Optional: Target runtime base (slim, alpine, distroless, scratch)
  • Optional: Size budget for final image

Steps

Step 1: Identify Build vs Runtime Dependencies

CategoryBuild StageRuntime Stage
Compilersgcc, g++, rustcNot needed
Package managersnpm, pip, cargoSometimes (interpreted langs)
Dev headers-dev packagesNot needed
Source codeFull source treeOnly compiled output
Test frameworksjest, pytestNot needed

Step 2: Structure the Multi-Stage Build

Core pattern: build in fat image, copy artifacts to slim image.

# ---- Build Stage ----
FROM <build-image> AS builder
WORKDIR /src
COPY <dependency-manifest> .
RUN <install-dependencies>
COPY . .
RUN <build-command>

# ---- Runtime Stage ----
FROM <runtime-image>
COPY --from=builder /src/<artifact> /<dest>
EXPOSE <port>
CMD [<entrypoint>]

Step 3: Apply Language-Specific Patterns

Node.js (pruned node_modules)

FROM node:22-bookworm AS builder
WORKDIR /src
COPY package.json package-lock.json ./
RUN npm ci
COPY . .
RUN npm run build && npm prune --omit=dev

FROM node:22-bookworm-slim
RUN groupadd -r app && useradd -r -g app app
WORKDIR /app
COPY --from=builder /src/dist ./dist
COPY --from=builder /src/node_modules ./node_modules
COPY --from=builder /src/package.json .
USER app
EXPOSE 3000
CMD ["node", "dist/index.js"]

Python (virtualenv copy)

FROM python:3.12-bookworm AS builder
WORKDIR /src
RUN python -m venv /opt/venv
ENV PATH="/opt/venv/bin:$PATH"
COPY requirements.txt .
RUN pip install --no-cache-dir -r requirements.txt
COPY . .

FROM python:3.12-slim-bookworm
COPY --from=builder /opt/venv /opt/venv
ENV PATH="/opt/venv/bin:$PATH"
WORKDIR /app
COPY --from=builder /src .
RUN groupadd -r app && useradd -r -g app app
USER app
EXPOSE 8000
CMD ["python", "app.py"]

Go (static binary to scratch)

FROM golang:1.23-bookworm AS builder
WORKDIR /src
COPY go.mod go.sum ./
RUN go mod download
COPY . .
RUN CGO_ENABLED=0 GOOS=linux go build -ldflags="-s -w" -o /server ./cmd/server

FROM scratch
COPY --from=builder /etc/ssl/certs/ca-certificates.crt /etc/ssl/certs/
COPY --from=builder /server /server
EXPOSE 8080
ENTRYPOINT ["/server"]

Rust (static musl binary)

FROM rust:1.82-bookworm AS builder
RUN apt-get update && apt-get install -y musl-tools && rm -rf /var/lib/apt/lists/*
RUN rustup target add x86_64-unknown-linux-musl
WORKDIR /src
COPY Cargo.toml Cargo.lock ./
RUN mkdir src && echo "fn main() {}" > src/main.rs \
    && cargo build --release --target x86_64-unknown-linux-musl \
    && rm -rf src
COPY . .
RUN touch src/main.rs && cargo build --release --target x86_64-unknown-linux-musl

FROM scratch
COPY --from=builder /src/target/x86_64-unknown-linux-musl/release/myapp /myapp
EXPOSE 8080
ENTRYPOINT ["/myapp"]

Got: Final image has only runtime and compiled artifacts.

If fail: Check COPY --from=builder paths. Use docker build --target builder to debug build stage.

Step 4: Choose Runtime Base

BaseSizeShellUse Case
scratch0 MBNoStatic Go/Rust binaries
gcr.io/distroless/static~2 MBNoStatic binaries + CA certs
gcr.io/distroless/base~20 MBNoDynamic binaries (libc)
*-slim50-150 MBYesInterpreted languages
alpine~7 MBYesWhen shell access needed

Note: Alpine uses musl libc. Some Python wheels and Node native modules may not work. Prefer -slim (glibc) for interpreted languages.

Step 5: Build Args Across Stages

ARG APP_VERSION=0.0.0

FROM golang:1.23 AS builder
ARG APP_VERSION
RUN go build -ldflags="-X main.version=${APP_VERSION}" -o /server .

FROM gcr.io/distroless/static
COPY --from=builder /server /server
ENTRYPOINT ["/server"]

Build with: docker build --build-arg APP_VERSION=1.2.3 .

Note: ARG before FROM is global. Each stage must re-declare ARG to use it.

Step 6: Compare Image Sizes

# Build both variants
docker build -t myapp:fat --target builder .
docker build -t myapp:slim .

# Compare sizes
docker images --format "table {{.Repository}}\t{{.Tag}}\t{{.Size}}" | grep myapp

Got: Production image 50-90% smaller than build stage.

Checks

  • docker build finishes for all stages
  • Final image has no build tools (compilers, dev headers)
  • docker run works from slim image
  • Image size significantly smaller vs single-stage
  • COPY --from=builder paths right
  • No source code leaks into production image

Pitfalls

  • Missing runtime libraries: Compiled code may need shared libraries (libc, libssl). Test slim image thoroughly.
  • Broken COPY --from paths: Artifact path must match exactly. Use docker build --target builder then docker run --rm builder ls /path to debug.
  • Alpine musl issues: Native Node.js addons and some Python packages fail on Alpine. Use -slim instead.
  • Global ARG scope: ARG declared before FROM is available to FROM lines only. Re-declare inside each stage that needs it.
  • Forgetting CA certificates: scratch has no certificates. Copy /etc/ssl/certs/ca-certificates.crt from builder or use distroless.

See Also

  • create-dockerfile - single-stage general Dockerfiles
  • create-r-dockerfile - R-specific Dockerfiles with rocker images
  • optimize-docker-build-cache - layer caching and BuildKit features
  • setup-compose-stack - compose configurations using multi-stage images
保存したスキル