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 (28)
✍️ Sample PCA Questions & Answers
1. 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.
2. 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.
3. 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.
4. 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.
5. 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.
6. What are histograms used for in Prometheus?
Prometheus typically uses a pull model, but short-lived jobs (like batch scripts or cron jobs) may not exist long enough for Prometheus to scrape them directly. The Pushgateway acts as an intermediary, allowing these ephemeral jobs to push their metrics to it. Prometheus then scrapes the Pushgateway, ensuring that metrics from short-lived processes are collected and stored for monitoring.