PCA Study Guide 2026
Everything you need to pass the PCA exam in one place: the exam format, every topic to study, real practice questions with explanations, flashcards, and full-length practice tests. Free, no sign-up needed.
📋 PCA Exam Format at a Glance
📚 PCA Topics to Study (44)
✍️ Sample PCA Questions & Answers
1. Which TSDB concept represents a contiguous on-disk directory containing immutable compressed samples for a fixed time range?
A TSDB block is a directory (e.g., 01BX…) holding an index, chunks, and metadata for a specific time range, produced by compaction from the WAL.
2. Which relabeling action renames all labels matching a regex by applying a replacement pattern to their names?
`labelmap` applies the regex to all label *names* and renames matching labels according to the replacement pattern, useful for promoting meta-labels.
3. In a recording rule, what does the `labels` field allow you to do?
The labels field in a recording rule attaches additional static labels to all series written by that rule.
4. What does the `group_left` modifier do in a PromQL join, commonly used in recording rules?
group_left allows a many-to-one vector matching where multiple left-side series match one right-side series, copying right-side labels onto the result.
5. In a Prometheus scrape_config, what does `scheme: https` combined with an empty `tls_config` result in by default?
Without explicit `ca_file` or `insecure_skip_verify`, Prometheus validates the target's certificate against the host system's default CA bundle.
6. What does the `__address__` label represent in Prometheus target discovery?
`__address__` holds the `host:port` that Prometheus uses to construct the scrape URL for a target.