The correct answer is D: Metrics. Metrics are numeric time-series measurements collected at regular intervals, making them ideal for plotting resource consumption over time and forecasting future exhaustion. In Kubernetes, this includes CPU usage, memory usage, disk I/O, network throughput, filesystem usage, Pod restarts, and node allocatable vs requested resources. Because metrics are structured and queryable (often with Prometheus), you can compute rates, aggregates, percentiles, and trends, and then apply forecasting methods to predict when a resource will run out.
Logs and traces have different purposes. Logs are event records (strings) that are great for debugging and auditing, but they are not naturally suited to continuous quantitative plotting unless you transform them into metrics (log-based metrics). Traces capture end-to-end request paths and latency breakdowns; they help you find slow spans and dependency bottlenecks, not forecast CPU/memory exhaustion. stdout is just a stream where logs might be written; by itself it’s not an observability data type used for capacity trending.
In Kubernetes observability stacks, metrics are typically scraped from components and workloads: kubelet/cAdvisor exports container metrics, node exporters expose host metrics, and applications expose business/system metrics. The metrics pipeline (Prometheus, OpenTelemetry metrics, managed monitoring) enables dashboards and alerting. For resource exhaustion, you often alert on “time to fill” (e.g., predicted disk fill in < N hours), high sustained utilization, or rapidly increasing error rates due to throttling.
Therefore, the most appropriate data stream for plotting consumption and predicting exhaustion is Metrics, option D.
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