If you’re new to Tracer or want a conceptual overview, see How Tracer fits in your stack.
What Prometheus does well
Prometheus is designed for metric collection and querying. It provides:- Time-series storage for reported metrics
- Pull-based scraping from exporters and instrumented services
- Label-based querying and aggregation
- Integration with alerting systems
What Prometheus does not observe
Prometheus records metrics that are emitted and scraped at intervals. It does not observe execution directly and does not have inherent awareness of pipeline or task structure. It does not show:- Execution behavior inside processes or containers
- CPU vs I/O vs memory contention during task execution
- Short-lived processes that start and finish between scrapes
- Idle time hidden by aggregated utilization
- How metrics relate to pipeline runs, tasks, or tools
- How cost maps to actual execution rather than to resource uptime
Why this gap matters
Scientific pipelines often involve heterogeneous tools, nested execution, and short-lived subprocesses. When relying on scraped metrics alone, teams can see that resources were used, but not how work progressed. As a result:- Performance bottlenecks must be inferred from aggregates
- Idle or blocked execution may appear as normal utilization
- Cost is attributed to infrastructure time, not execution units
- Custom metrics and labels accumulate assumptions about runtime behavior
What Tracer adds
Tracer observes execution directly from the host and container runtime and adds:- Observed CPU, memory, disk, and network behavior
- Visibility into short-lived processes and nested tools
- Attribution by pipeline, run, task, or execution unit
- Cost mapping aligned with observed runtime activity
Example: scraped metrics versus observed execution
Prometheus shows sustained CPU utilization during a pipeline run. Tracer reveals that:- CPU usage remains low for most tasks
- Execution is dominated by disk I/O wait
- Short-lived helper processes consume significant time
Observability comparison
This comparison highlights the difference between scraped metrics and execution-level observation.
What Tracer does not replace
Tracer is not a general-purpose metrics backend.- It does not replace Prometheus for collecting arbitrary application metrics
- It does not replace long-term storage for unrelated or user-defined metrics
- It does not replace metric-based alerting outside execution behavior
- It does not replace dashboards built from non-execution telemetry
When to use Tracer with Prometheus
Tracer is most useful alongside Prometheus when teams need to:- Understand pipeline behavior beyond scraped metrics
- Diagnose performance issues involving short-lived tasks
- Attribute resource usage and cost to workflows or tools
- Reduce manual metric instrumentation and correlation

