Could you explain the main metrics used to assess the health of services in monitoring, known as the 4 golden signals?

4 golden signals are key metrics for monitoring the health of services:

1. Latency — the response time of the service. It is important to track not only the average time but also percentiles (e.g., 95th, 99th) to see rare but significant delays.

2. Traffic — the number of requests or operations processed by the service per unit of time. Helps understand the load on the system.

3. Errors — the number of failed requests or operations. A high error rate indicates problems in the service.

4. Saturation — the degree of resource utilization (CPU, memory, disk, network). Shows how close the system is to its capacity limits.

These metrics help quickly identify and respond to issues in service operation.