Production Docker Hardening

This skill transforms demo-quality Docker setups into production-grade container infrastructure. Every recommendation here comes from real incidents: breached containers running as root, 2GB images that take 8 minutes to deploy, secrets leaked into image layers. Follow this guide and none of that happens on your watch.

1. Multi-Stage Builds

Single-stage builds ship compilers, build tools, and source code to production. Multi-stage builds fix this by separating the build environment from the runtime environment.

Python example (builder + distroless):

# syntax=docker/dockerfile:1

FROM python:3.12-slim AS builder
WORKDIR /build
COPY requirements.txt .
RUN pip install --no-cache-dir --no-compile --prefix=/install -r requirements.txt