What are telemetry and monitoring used for? What technologies have you worked with?

Telemetry and monitoring are needed for collecting, analyzing, and visualizing data about the operation of applications and infrastructure. This helps quickly detect and resolve issues, optimize performance, and ensure service stability.

Telemetry collects metrics, logs, and traces, which provide a comprehensive view of the system's state.

In my experience, I have used:

• Prometheus for collecting and storing metrics;
• Grafana for data visualization;
• Jaeger for distributed tracing;
• ELK Stack (Elasticsearch, Logstash, Kibana) for log analysis.

For example, with Prometheus, you can set up collection of response time metrics for APIs, and with Grafana, you can build dashboards to monitor these metrics in real-time.