Prometheus is an open-source systems monitoring and alerting toolkit originally built at SoundCloud. Since its inception in 2012, Prometheus has become a standalone open-source project and maintained independently by the Prometheus community.
To run Prometheus in a Docker container, you can use either of the following methods:
docker run -p 9090:9090 -v ./prometheus.yml:/etc/prometheus/prometheus.yml prom/prometheusdocker-compose up- Single Machine Operation:
- Prometheus is designed to run on a single machine.
- It is not distributed in nature, meaning it cannot be horizontally scaled across multiple machines.
- Prometheus operates on a single load process.
Prometheus offers robust monitoring and alerting features, including:
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Multi-Dimensional Data Model:
- Time series data is identified by metric name and key-value pairs.
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PromQL:
- A flexible query language designed to leverage the multi-dimensional data model.
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Autonomous Nodes:
- Prometheus servers do not rely on distributed storage; each server node operates independently.
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Pull-Based Data Collection:
- Time series collection is performed via a pull model over HTTP.
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Push Support:
- Time series data can also be pushed using an intermediary gateway.
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Service Discovery:
- Targets are discovered dynamically using service discovery or static configuration.
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Graphing and Dashboarding:
- Prometheus supports multiple modes for graphing and creating dashboards.
A counter is a cumulative metric that only increases. It is typically used to count events or conditions over time.
- Example: Counting the number of HTTP requests.
A gauge is a metric that can go up and down. It is often used to measure values that fluctuate.
- Example: Measuring the current memory usage or the current number of active users.
A histogram samples observations (usually things like request durations or response sizes) and counts them in configurable buckets. It also provides a sum of all observed values. It's a cummulative type.
- Example: Measuring the duration of HTTP requests.
- No Horizontal Scaling:
- Prometheus cannot run on multiple machines simultaneously for a single data load process.
For more information, visit the official Prometheus documentation.