Cloud-Native Microservices With Kubernetes - 2nd Edition

White-Box Monitoring vs. Black-Box Monitoring

To understand observability and its connection to monitoring, it helps to look at two main perspectives: white-box monitoring and black-box monitoring.

Black-box monitoring looks from the outside. It checks the overall health of servers and resources like CPU usage, memory consumption, disk space, and system load. It answers the question: "Is the service up and responding as expected?" rather than "Why is it behaving this way?"

White-box monitoring, in contrast, focuses on what happens inside the system. It tracks internal application metrics such as HTTP requests handled by a web server, database query counts, or cache hit ratios. These metrics offer direct insight into how the application behaves under different conditions.