- What is the observability of a system?
It's the capacity of a system. It lets you know what its internal state is.
- What are the different severity levels that are available in logs by default?
In order of increasing severity, the different severity levels are DEBUG, INFO, WARNING, ERROR, and CRITICAL.
- What are metrics used for?
Metrics allow you to find out the aggregated statuses of the events that are occurring on the system and allow you to understand the general state of the system.
- Why do you need to add a request ID to the logs?
You need to add a request ID to the logs so that you can group all of the logs that correspond to the same request.
- What kinds of metrics are available in Prometheus?
Counters, which count a particular event; gauges, which keep track of a value that can go either up or down; and histograms (or summaries), which track events...