Bits of .NET

❤️ Is Your Container Actually Working?

Container running but app crashed? Health checks test app responsiveness. Automatically restart unhealthy containers.

📝 Health Check in Dockerfile

# Web app
HEALTHCHECK --interval=30s --timeout=3s --start-period=5s --retries=3 \
  CMD curl -f http://localhost/ || exit 1

# Database
HEALTHCHECK --interval=30s --timeout=10s --retries=5 \
  CMD pg_isready -U postgres || exit 1

# Redis
HEALTHCHECK --interval=30s --timeout=3s --retries=3 \
  CMD redis-cli ping || exit 1

🎯 Docker Compose Healthcheck

services:
  app:
    image: myapp
    healthcheck:
      test: ["CMD", "curl", "-f", "http://localhost:8080/health"]
      interval: 30s
      timeout: 5s
      retries: 3
      start_period: 10s

depends_on:
  postgres:
    condition: service_healthy

💡 Commands

• docker ps (shows health status)
• docker inspect –format='{{json .State.Health}}’ container_name
• docker events (see health events)
• Kubernetes liveness probes (alternative)