Common Failure Modes in Containerized Systems and Prevention

# docker-compose.yml
services:
  app:
    deploy:
      resources:
        limits:
          memory: 512M
        reservations:
          memory: 256M

services:
  app:
    deploy:
      resources:
        limits:
          cpus: '1.0'

# Dockerfile
HEALTHCHECK --interval=30s --timeout=3s --start-period=40s \
  CMD curl -f http://localhost:8080/health || exit 1

services:
  app:
    restart: unless-stopped
    # Options: no, always, on-failure, unless-stopped

services:
  app:
    ports:
      - "8080:8080"  # host:container

services:
  app:
    dns:
      - 8.8.8.8
      - 8.8.4.4

# Fix permissions
RUN chown -R appuser:appuser /app
USER appuser

services:
  app:
    volumes:
      - ./data:/app/data:ro  # Read-only
      - cache:/app/cache

# Bad: Changes invalidate cache
COPY . .
RUN npm install

# Good: Layer caching
COPY package*.json ./
RUN npm install
COPY . .

services:
  app:
    logging:
      driver: "json-file"
      options:
        max-size: "10m"
        max-file: "3"

RUN useradd -m appuser
USER appuser

services:
  app:
    secrets:
      - db_password
    environment:
      DB_PASSWORD_FILE: /run/secrets/db_password