Jaeger vs Prometheus: What are the differences?

Key Differences between Jaeger and Prometheus

Jaeger and Prometheus are both popular monitoring tools used in the field of observability. While they serve similar purposes, there are several key differences between the two:

1. Data Model: Jaeger focuses on distributed tracing, capturing and analyzing traces of requests as they propagate throughout a distributed system. On the other hand, Prometheus is a time-series-based monitoring system, collecting and storing metrics data over time.

2. Monitoring Approach: Jaeger provides a more detailed view of request flow in a distributed system, enabling deep performance analysis and troubleshooting. Prometheus, on the other hand, offers a broader scope of monitoring, focusing on metrics and alerting based on thresholds and rules.

3. Instrumentation: Jaeger requires explicit instrumentation in the code to capture and propagate trace information. Prometheus, on the other hand, relies on a pull-based model where it scrapes metrics from instrumented endpoints.

4. Data Storage: Jaeger uses a distributed storage backend like Elasticsearch or Cassandra to store highly detailed trace information. Prometheus comes with its own built-in time-series database designed for efficient storage and querying of metrics data.

5. Query Language: Jaeger provides a query language called Jaeger Query Language (JQL) for retrieving and analyzing trace data. Prometheus uses its own query language called PromQL, specifically designed for querying time-series metrics.

6. Alerting: Jaeger does not provide built-in support for alerting. Prometheus, on the other hand, has extensive alerting capabilities, supporting alert rules and notifications based on metric thresholds.

In Summary, Jaeger focuses on distributed tracing and provides in-depth analysis of request flow, while Prometheus is a more general monitoring system that collects and stores metrics data over time, with built-in alerting capabilities.