Metrics, Health Checks, and Monitoring
Imagine you're running an e-commerce application built with microservices. One afternoon, customers start complaining that checkout is unusually slow. Some payments are failing, and a few users cannot place orders at all.
You check the application logs, but there are thousands of entries across different services. Nothing immediately explains the problem. How do you know which service is unhealthy? How many users are affected? Is the problem getting worse?
This is where metrics, health checks, and monitoring become essential. These three concepts work together to help engineers understand the health and performance of a distributed application.
- Metrics measure how services behave over time.
- Health checks determine whether service instances are running and capable of handling requests.
- Monitoring continuously observes these signals and alerts engineers when something goes wrong.
In a microservices architecture, where dozens of independently deployed services communicate over a network, these capabilities are fundamental to operating a reliable system.