PCA Cheat Sheet 2026

The 30 highest-yield PCA facts, distilled from real exam questions. Print it, save it as a PDF, or study it here — free, no sign-up.

1. What is the Prometheus exposition format, and which content type does it use? → A text-based line format exposed over HTTP with Content-Type: text/plain; version=0.0.4
2. What content type must a Prometheus metrics endpoint return for the text exposition format? → text/plain; version=0.0.4
3. What happens to 'job' and 'instance' labels when metrics are federated from one Prometheus server to another? → They are preserved as-is from the originating Prometheus server
4. In Prometheus web configuration, what does the `http2` field control? → Whether Prometheus serves its own API over HTTP/2
5. Which flag controls how long Prometheus retains data when using time-based retention? → --storage.tsdb.retention.time
6. What is the role of Grafana in Prometheus? → To visualize data in dashboards
7. How are Prometheus metrics structured? → As logs and alerts
8. Which exporter is the standard choice for exposing Linux host-level metrics such as CPU, memory, and disk? → node_exporter
9. What does the `remote_read` configuration in Prometheus enable? → Querying historical data from a remote storage backend when local data is unavailable
10. How does Prometheus handle a bearer token stored in a file for scrape authentication? → It reads the token file on each scrape, automatically picking up rotated tokens
11. Which Prometheus configuration option allows scraping a target that uses a self-signed TLS certificate without verification? → insecure_skip_verify: true
12. What OAuth2 configuration capability does Prometheus support natively in scrape_configs? → Client credentials flow to obtain a bearer token before scraping
13. What is the main purpose of metrics in Prometheus? → To provide quantitative data on system performance
14. Which exporter is the standard choice for exposing Linux/Unix OS-level metrics like CPU, memory, and disk to Prometheus? → node_exporter
15. What is the primary role of a Prometheus exporter? → Translating third-party system metrics into Prometheus exposition format
16. What is the purpose of `ca_file` in a Prometheus tls_config block? → It specifies the CA certificate used to verify the target's TLS certificate
17. In Prometheus, what is the role of `source_labels` in a relabel_configs entry? → They specify which existing labels are read as input for the relabeling action
18. Why is it important to set up proper alerting in Prometheus? → To detect and address issues proactively
19. What does the `labelmap` action in relabel_configs do? → Copies all labels matching a regex into new labels with transformed names
20. In Prometheus file-based service discovery, which file format is used to define static targets? → JSON or YAML
21. Which mutual TLS (mTLS) configuration field in Prometheus scrape_config specifies the client certificate to present to the target? → cert_file under tls_config
22. When using Kubernetes service discovery, which role discovers individual pod endpoints rather than services? → pod
23. How can Prometheus data be exported for external analysis? → By exporting to CSV
24. What is the Prometheus pushgateway used for? → Accepting metrics pushed by short-lived jobs that cannot be scraped
25. What naming convention does Prometheus recommend for recording rule metric names? → level:metric:operations (e.g., job:http_requests_total:rate5m)
26. What is a key drawback of using the Prometheus Pushgateway for all metrics collection? → It can serve stale metrics from jobs that have already finished, masking failures
27. What is the primary role of Prometheus in monitoring? → To visualize data
28. What is the security benefit of using Prometheus's `--storage.tsdb.no-lockfile` flag in specific deployments? → It allows multiple read-only Prometheus instances to share the same TSDB directory safely
29. Which Prometheus configuration block allows per-target scrape parameter overrides such as custom query params? → params
30. How does Prometheus scrape the blackbox_exporter to probe a specific target URL? → The target URL is passed as a query parameter (?target=) in the scrape URL