containerization

Containerization & Orchestration

Build, ship, and run applications with Docker and Kubernetes following production best practices.

When to Use

• Building Docker images for applications
• Writing Docker Compose for multi-service local development
• Deploying to Kubernetes clusters
• Creating CI/CD pipelines that build and push container images
• Migrating from VMs to containers

Decision Tree

Containerizing an application?
+- Single service, local dev?
| - Dockerfile only
+- Multi-service, local dev?
| - Docker Compose
+- Production deployment?
| +- Simple (1-3 services)?
| | - Docker Compose + managed hosting (Azure Container Apps, ECS)
| - Complex (many services, scaling)?
| - Kubernetes (AKS, EKS, GKE)
- CI/CD pipeline?
 - Multi-stage Dockerfile + registry push

Quick Start

# Build image
docker build -t myapp:1.0 .

# Run container
docker run -d -p 3000:3000 myapp:1.0

# Multi-service (Docker Compose)
docker compose up -d

# Scan for vulnerabilities
docker scout quickview myapp:1.0

Dockerfile Best Practices

Multi-Stage Builds (Recommended)

# Stage 1: Build
FROM node:24-alpine AS build
WORKDIR /app
COPY package*.json ./
RUN npm ci --production=false
COPY . .
RUN npm run build

# Stage 2: Production
FROM node:24-alpine AS production
WORKDIR /app
RUN addgroup -g 1001 appgroup && adduser -u 1001 -G appgroup -s /bin/sh -D appuser
COPY --from=build /app/dist ./dist
COPY --from=build /app/node_modules ./node_modules
COPY --from=build /app/package.json ./
USER appuser
EXPOSE 3000
HEALTHCHECK --interval=30s --timeout=3s CMD wget -qO- http://localhost:3000/health || exit 1
CMD ["node", "dist/server.js"]

.NET Multi-Stage

FROM mcr.microsoft.com/dotnet/sdk:9.0 AS build
WORKDIR /src
COPY *.csproj ./
RUN dotnet restore
COPY . .
RUN dotnet publish -c Release -o /app/publish --no-restore

FROM mcr.microsoft.com/dotnet/aspnet:9.0
WORKDIR /app
RUN adduser --disabled-password --gecos '' appuser
COPY --from=build /app/publish .
USER appuser
EXPOSE 8080
HEALTHCHECK --interval=30s --timeout=3s CMD curl -f http://localhost:8080/health || exit 1
ENTRYPOINT ["dotnet", "MyApp.dll"]