OpenCost: what it is, what it fixes, and where it stands today

A practical rundown for platform engineers building cloud-native apps

If your team runs workloads on Kubernetes and you still treat cloud spend as a vague line item on an invoice, OpenCost is worth a quick, serious look.

Money is important, more and more every day, and when you are in the cloud, holding the money is a real challenge 💸.

That’s why, in today’s issue, I will give you an overview of OpenCost, a CNCF project.

But first things first, what OpenCost is?

It’s an open-source, vendor-neutral project that brings real-time cost visibility and allocation to Kubernetes and cloud infrastructure so engineering teams and platform teams can make data-driven decisions about efficiency and showback/chargeback.

Nice definition, right? For me, that kind of definition are okeysh, but I really need to understand what it does.

🤔 What OpenCost actually does

• Measures & allocates cloud and Kubernetes costs in near real-time (CPU, memory, storage, network, GPU, etc.).

• Maps cloud billing to Kubernetes concepts, so you can answer “how much did team X spend last week?” or “which deployment is causing the spike?”

• Supports multi-cloud and on-prem via integrations with AWS/Azure/GCP billing APIs and customizable pricing models.

Another thing I see super useful for real life is that OpenCost can give you the money you burn by namespace. Why is it important for me? Because, usually, the resources from the different dev teams are deployed in separate namespaces, hence, each dev team can see how much their stuff costs.

From there, the next step is obvious. Having namespace costs allows you to:

• Allocate expenses directly to teams or products (if each team uses its own namespace).

• Quickly identify which namespace is consuming the most resources or money.

• Integrate with showback/chargeback processes within your platform.

Last but not least, I think it’s important to mention that OpenCost is Kubernetes-native: you typically deploy it into your cluster(s) (Helm charts available), and it relies on existing metrics sources (Prometheus) and cloud billing data for price lookups.

🎯 Problems it solves

When you start deploying your SaaS product into a Kubernetes clusters you face many challenges. Some of the ones related to costs are:

• Opaque Kubernetes spend. Kubernetes abstracts resources, but that abstraction hides who/what is actually driving costs. OpenCost restores accountability.

• Ownership breaks down in shared Kubernetes platforms. Kubernetes clusters are shared by design. Cloud providers bill at the account or subscription level, but teams think in terms of services and products. Without a clear ownership model, questions like “which team is driving this cost?” are hard to answer. Manual mappings and spreadsheets 😱 appear as workarounds.

• Kubernetes hides the true cost of “idle”. Over-provisioning, shared nodes, and autoscaling make it hard to understand idle capacity and inefficiencies. OpenCost surfaces these hidden costs, allowing platform teams to reason about efficiency in concrete, measurable terms.

🧐 State of the project

OpenCost is a CNCF project that progressed from Sandbox into Incubating. It was accepted into CNCF in mid-2022 and promoted to Incubating in October 2024, reflecting growing community adoption and governance maturity.

The project is actively maintained (GitHub repo, releases, and community contributors) and has continued to publish roadmaps and year-in-review notes describing frequent releases and expanding integrations.

Recent public updates indicate priorities around refining cost models, improving supply-chain security for cost data, and adding features to better track emerging workloads (for example: AI/ML usage costs).

✨ Summary

Many companies include the cost assessment before implementing the solution. Others (lucky you) just jump into implementation, and then the problem of understanding the cost comes.

In any case, whether you made an estimation, or you just don’t know, nowadays (always?), you must have visibility on the costs of the applications and resources deployed in your Kubernetes, and OpenCost is one of the options available.

That’s all for today!

I would love to hear about your experiences using OpenCost or any other tool for measuring the costs of cloud applications. Drop me a comment or reply to this email; I will read it and come back to you!

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