Container Orchestration

Docker and Kubernetes patterns for containerized applications.

Dockerfile Best Practices

# Use specific version, not :latest
FROM python:3.11-slim AS builder

# Set working directory
WORKDIR /app

# Copy dependency files first (better caching)
COPY requirements.txt .
RUN pip install --no-cache-dir -r requirements.txt

# Copy application code
COPY src/ ./src/

# Production stage (multi-stage build)
FROM python:3.11-slim

WORKDIR /app

# Create non-root user
RUN useradd --create-home appuser
USER appuser

# Copy from builder
COPY --from=builder /app /app

# Set environment
ENV PYTHONUNBUFFERED=1

# Health check
HEALTHCHECK --interval=30s --timeout=3s \
  CMD curl -f http://localhost:8000/health || exit 1

EXPOSE 8000
CMD ["python", "-m", "uvicorn", "src.main:app", "--host", "0.0.0.0"]

Dockerfile Rules

DO:
- Use specific base image versions
- Use multi-stage builds
- Run as non-root user
- Order commands by change frequency
- Use .dockerignore
- Add health checks

DON'T:
- Use :latest tag
- Run as root
- Copy unnecessary files
- Store secrets in image
- Install dev dependencies in production