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Networking · head to head

Prometheus vs Rook

Prometheus logo

Prometheus

Networking

Open source monitoring and alerting toolkit for cloud native environments

From
Free
Rated
-
Full reviewWebsite
Rook logo

Rook

Cloud

Kubernetes operator that deploys and manages Ceph storage clusters

From
Free
Rated
-
Full reviewWebsite

The short version

  • Each has a real cost: Prometheus not suitable for per-request billing as collected data lacks 100% accuracy; Rook rook automates Ceph but does not abstract it, so an incident still demands Ceph expertise, and organisations without it end up hiring consultants at exactly the wrong moment.
  • They diverge on capability: Prometheus covers Multi-dimensional Data Model, Rook covers Ceph operator.
  • Prices and features above were last checked on 1 September 2026.

Where they differ

Only the attributes on which Prometheus and Rook actually diverge.

Attributes where Prometheus and Rook differ
AttributePrometheusRook
Pricing modelopen-sourceOpen source, no licence fee
PlatformsLinux, macOS, WindowsLinux, Kubernetes
CategoryNetworkingCloud
Founded2015Unknown

Identical on both: starting price (Free), free tier (Yes), user rating (Not yet rated).

What each one covers

Drawn from each product's published feature list. An absence here means we hold no record of it - not that the product lacks it.

Only in Prometheus

  • Multi-dimensional Data Model
  • PromQL Query Language
  • Pull-based Collection
  • Service Discovery
  • Alerting Rules
  • Federation
  • Local Storage
  • Grafana

Only in Rook

  • Ceph operator
  • Block, file and object
  • Erasure coding
  • CSI driver
  • Automated upgrades
  • Multi-cluster mirroring

What people use each for

The jobs each tool is most often brought in to do.

Prometheus

  • Monitoring and alerting systemnot Rook
  • Time-series databasenot Rook
  • Infrastructure metrics collectionnot Rook

Rook

  • An on-premises Kubernetes platform needing block, shared filesystem and S3 storage without buying three productsnot Prometheus
  • A team that already runs Ceph and wants its lifecycle managed declaratively inside Kubernetesnot Prometheus
  • A large cluster where three-way replication overhead is unaffordable and erasure coding is requirednot Prometheus
  • An organisation building a private cloud that cannot use managed cloud storage services for residency reasonsnot Prometheus

Where each one falls short

Documented limitations, not opinions. Every one is a constraint you would hit in normal use.

Prometheus

  • Not suitable for per-request billing as collected data lacks 100% accuracy
  • Hard limit on scrape body size; large responses cause scrape failure
  • Per-scrape sample limit enforced; exceeding limit marks targets as failed
  • Not designed for long-term durable storage; optimised for metrics collection

Rook

  • Rook automates Ceph but does not abstract it, so an incident still demands Ceph expertise, and organisations without it end up hiring consultants at exactly the wrong moment.
  • There is no vendor and no SLA; the realistic commercial support routes are IBM Red Hat OpenShift Data Foundation or an independent Ceph consultancy, both of which change the cost picture entirely.
  • Ceph is resource hungry, needing substantial memory and dedicated disks per OSD, so the hardware cost of a properly sized cluster is often underestimated.
  • Recovery and rebalancing after a disk or node failure generates heavy background input and output that can degrade application performance for hours, which surprises teams sizing for steady state.
  • Minimum viable clusters require several nodes with several disks each, so it is impractical at small scale and the entry hardware cost exceeds simpler alternatives.

Pricing, plan by plan

Prometheus

Free
  • Prometheus (Open Source)Free
    • 100% open source
    • Community-driven project
    • Apache 2 License

Rook

Free
  • RookFree
    • Apache 2.0 licensed, no licence fee
    • Graduated CNCF project
    • Community support via GitHub and Slack only

Which should you pick?

Choose Prometheus if

  • You need multi-dimensional data model.
  • You want to start without paying.
  • You work on Linux, macOS, Windows.
  • You also want promql query language.
Prometheus review

Choose Rook if

  • You need ceph operator.
  • You want to start without paying.
  • You work on Linux, Kubernetes.
  • You also want block, file and object.
Rook review

Questions people ask

Is Prometheus or Rook better?
Neither clearly leads. Prometheus starts at Free and Rook at Free, and user ratings are close enough to be indistinguishable. Choose on capability and platform support.
Which is cheaper, Prometheus or Rook?
Prometheus starts at Free and Rook at Free.
Does Prometheus or Rook run on more platforms?
Prometheus runs on Linux, macOS, Windows. Rook runs on Linux, Kubernetes.
Can I use Prometheus for free?
Both have a free tier, so you can try either at no cost before committing.
What is Prometheus best used for?
Prometheus is most often used for monitoring and alerting system, time-series database, infrastructure metrics collection. Of those, monitoring and alerting system and time-series database are not what Rook is typically brought in for.
What can Prometheus do that Rook cannot?
Prometheus covers Multi-dimensional Data Model, PromQL Query Language, Pull-based Collection, Service Discovery. Rook covers Ceph operator, Block, file and object, Erasure coding, CSI driver.

Answered from the vendors’ own pages

Prometheus: What does Prometheus cost?

Prometheus is completely free and open source. There are no pricing tiers or paid plans. The entire project is licensed under Apache 2 and hosted on GitHub.

Source
Rook: Who supports it in production?

Nobody by default. IBM sells Red Hat OpenShift Data Foundation, which is supported Rook and Ceph, and independent consultancies sell Ceph support. Decide this before deployment.

Prometheus: Is Prometheus commercial software or free?

Prometheus is 100% open source and community-driven. It is a CNCF graduated project with no commercial restrictions or licensing fees.

Source
Rook: Does it need Ceph knowledge?

Yes. Rook handles deployment and routine operations, but troubleshooting a degraded cluster is a Ceph skill and there is no way around it.

Prometheus: How is Prometheus licensed?

Prometheus is licensed under the Apache 2 License, which permits free use, modification, and distribution for commercial and non-commercial purposes.

Source
Rook: Can it replace an object storage appliance?

Functionally yes, through the RADOS gateway, but you take on the operations that an appliance vendor would otherwise carry.

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