Prometheus vs Thanos
A side-by-side comparison of two self-hosted monitoring & status options — licensing, setup difficulty, resource needs, and what each one replaces.
Prometheus
Metrics-based monitoring and alerting toolkit
VS
Thanos
Highly available Prometheus setup with long-term storage
| Feature | Prometheus | Thanos |
|---|---|---|
| Deploy effort | ≈5-minute setup | Under-an-hour setup |
| Health score | 100 · Excellent | 94 · Excellent |
| Category | Monitoring & Status | Monitoring & Status |
| License | Apache-2.0 | Apache-2.0 |
| Language | Go | Go |
| Setup difficulty | Medium | Hard |
| Min. RAM | 512 MB | 1,024 MB |
| Deployment | docker, binary, helm | docker, kubernetes, helm |
| GitHub stars | ★ 66,196 | ★ 14,214 |
| First released | 2015 | 2018 |
| Replaces | Datadog | Datadog, Grafana Cloud |
What are Prometheus and Thanos?
Prometheus
Prometheus is a metrics-based monitoring system and time-series database with a powerful query language and alerting. It targets engineers monitoring cloud-native infrastructure. It is deployed via Docker, binaries, or Helm.
- Pull-based metrics collection
- PromQL query language
- Built-in alerting rules
- Cloud-native standard
Thanos
Thanos extends Prometheus with global query view, unlimited retention, and high availability. It uses object storage to keep metrics cheaply for years while presenting a single query endpoint across many Prometheus instances.
- Global query view
- Unlimited metric retention
- Object storage backend
- Downsampling for fast queries
Prometheus vs Thanos: key differences
Both projects are written in Go. Prometheus is the lighter option, starting around 512 MB of RAM against 1,024 MB for Thanos. Prometheus is the more established project (first released 2015), while Thanos arrived in 2018. Prometheus has the considerably larger community, at 66,196 GitHub stars versus 14,214.
Why pick each one
Choose Prometheus if…
- Powerful query language
- Reliable and scalable
- Huge ecosystem
Watch out for
- No long-term storage by default
- Dashboards need Grafana
Choose Thanos if…
- Scales Prometheus to massive deployments
- Cheap long-term storage
Watch out for
- Complex multi-component architecture
- Steep learning curve
Frequently asked questions
Is Prometheus or Thanos better?
Prometheus is the stronger all-round pick: it has both the larger community and the simpler medium setup. Consider Thanos if its specific feature set fits your needs better.
Are Prometheus and Thanos free and open-source?
Yes. Prometheus is licensed under Apache-2.0 and Thanos under Apache-2.0. Both can be self-hosted at no software cost.
Can I run Prometheus and Thanos with Docker?
Prometheus: yes. Thanos: yes.
Which is lighter on resources, Prometheus or Thanos?
Prometheus has the smaller minimum footprint at 512 MB of RAM, compared to about 1,024 MB for Thanos. Real-world usage depends on library size, user count, and enabled features.