OpenCost

What OpenCost is

OpenCost is an open source project for measuring and allocating cloud infrastructure and container costs in real time. It was created by Kubecost and is now a Cloud Native Computing Foundation (CNCF) incubating project, maintained by a community of Kubernetes practitioners. You install it into a cluster, it reads what each pod requests and uses, and it prices that against your cloud provider's rates.

Why it matters for FinOps

A Kubernetes cluster shows up on the cloud bill as a handful of virtual machines, disks and load balancers. The bill cannot tell you that the payments team used 40% of those machines and the search team 10%. OpenCost fills that gap: it splits node, storage and network cost across namespaces, deployments, labels and teams, so shared clusters can be shown back or charged back fairly. It also reports idle capacity, the part of the cluster nobody requested, which is often the biggest saving.

What it covers

• Allocation by container, pod, namespace, controller and label, with CPU, memory, storage and network split out.
• Live pricing through the AWS, Azure and Google Cloud billing APIs, or custom prices for on-premises clusters.
• Out-of-cluster costs such as managed databases and object storage, so a team sees more than its pods.
• Open interfaces: a UI, an API and Prometheus metrics you can chart in Grafana.

Microsoft's AKS cost analysis add-on is built on OpenCost, which is a good sign of how widely its model of allocation is accepted.

How to learn with it

Install it on a local cluster (kind or minikube) or a small cloud cluster, deploy two sample apps in different namespaces with different requests, and compare the allocation report with what you expected. Then change the requests and watch idle cost move. That exercise teaches more about Kubernetes cost than any slide.

Prerequisites and time

You need basic Kubernetes (pods, namespaces, requests and limits) and Helm. Installing it takes an hour or two; learning to read allocation and idle cost well takes a few weeks of real use.

Free or paid

OpenCost is free and open source. Commercial tools such as Kubecost (now part of IBM) build on the same ideas with extra features, but you do not need them to learn.

Best for: platform and FinOps engineers who must answer "which team is this cluster cost for?"