docker-containerization-skill

What I do

I help you create, optimize, and secure Docker containers:

1. Dockerfile Authoring: Write production-grade Dockerfiles with multi-stage builds
2. Image Optimization: Reduce image size with distroless, Alpine, and layer strategies
3. Docker Compose: Design development and production compose configurations
4. Layer Caching: Structure builds for maximum cache efficiency
5. Health Checks: Implement proper health check endpoints and probes
6. Security Scanning: Scan images with hadolint (linting) and docker scout (vulnerabilities)

When to use me

Use this skill when:

• Writing or optimizing a Dockerfile for a new or existing project
• Setting up docker-compose for local development or production deployment
• Reducing Docker image size
• Debugging container build failures or slow builds
• Implementing health checks and graceful shutdown
• Setting up multi-container architectures
• Scanning containers for security issues
• Creating .dockerignore files

Related Skills

• opentofu-provisioning-workflow-skill: Handles infrastructure provisioning. This skill handles container image building and composition.
• security-audit-skill: Handles application-level security auditing. This skill handles container-specific security (image scanning, hadolint).

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Step 1: Dockerfile Templates

Node.js (Next.js)

FROM node:20-alpine AS base
RUN apk add --no-cache libc6-compat
WORKDIR /app

FROM base AS deps
COPY package.json pnpm-lock.yaml ./
RUN corepack enable pnpm && pnpm install --frozen-lockfile

FROM base AS builder
COPY --from=deps /app/node_modules ./node_modules
COPY . .
RUN corepack enable pnpm && pnpm build

FROM base AS runner
ENV NODE_ENV=production
RUN addgroup --system --gid 1001 nodejs && adduser --system --uid 1001 nextjs

COPY --from=builder /app/public ./public
COPY --from=builder --chown=nextjs:nodejs /app/.next/standalone ./
COPY --from=builder --chown=nextjs:nodejs /app/.next/static ./.next/static

USER nextjs
EXPOSE 3000
ENV PORT=3000 HOSTNAME="0.0.0.0"
CMD ["node", "server.js"]