FinOps in Kubernetes - 20 Answers

1. Why is the standard cloud bill for Kubernetes costs unusable? Cloud providers issue bills for instances (VMs). However, Kubernetes distributes these instances across many teams and apps. Without K8s-native tools, you only see the total sum, but not which service is causing the costs.

2. What is the difference between “Showback” and “Chargeback”? Showback makes costs visible to teams (raising awareness). Chargeback actually bills these costs to the teams or departments (financial responsibility).

3. How are costs fairly distributed in a shared cluster? By analyzing “Resource Requests.” Tools like Kubecost or OpenCost calculate a team’s share of the total costs based on CPU and RAM reservations within their namespaces.

4. What are “Idle Costs”? Costs for resources that are reserved but not used. If a cluster is 80% idle, you still pay for the full instances. FinOps aims to minimize this “slack.”

5. Why are “Resource Requests” more important for costs than actual consumption? Cloud providers charge based on the capacity of the nodes. Since Kubernetes schedules pods based on their requests, they occupy space on the nodes—regardless of whether the app actually uses the power or not.

6. What is “Bin Packing” and how does it save money? Bin Packing is a strategy where pods are packed as densely as possible onto as few nodes as possible to avoid unused fragments and to be able to shut down surplus nodes.

7. How does “Scale-to-Zero” help with cost optimization? Tools like KEDA can completely shut down workloads during no-load times (0 pods). This saves a lot of money, especially in dev/test environments and with asynchronous workers.

8. What is meant by “Rightsizing”? The process of adjusting a container’s resource requests and limits to its actual historical consumption. Oversized requests lead to waste, while undersized requests lead to performance issues.

9. What role do labels play in FinOps? Labels (e.g., team: marketing or env: prod) are the foundation for cost attribution. Without proper labeling, automated cost allocation to cost centers is impossible.

10. How do you handle “Shared Resources” like the load balancer or monitoring? These costs are recorded as “Unallocated Costs” and are usually distributed proportionally to total consumption or as a fixed amount across all teams.

11. What is “Spot Instance Orchestration”? The use of unused cloud capacity (Spot Instances), which can be up to 90% cheaper. Tools like Karpenter can safely use unstable spot instances for non-critical or fault-tolerant workloads.

12. How do you detect cost anomalies in real-time? Through monitoring alerts that trigger when a service’s daily costs suddenly deviate by a defined percentage (e.g., 20%) from the average.

13. What is the “FinOps culture” in engineering? The shift from “performance at any cost” to “cost-efficient engineering.” Developers take responsibility for the financial impact of their code and architecture.

14. Can storage costs (Persistent Volumes) be optimized? Yes, by deleting unused snapshots and using different storage classes for different workloads (e.g., standard HDD for backups, SSD for databases).

15. Why is “Egress Traffic” often a hidden cost driver? Data traffic between different cloud regions or to the internet is often charged at a high rate. FinOps strategies try to keep traffic within a zone (Topology Awareness).

16. How does “Quality of Service” (QoS) affect stability and costs? Kubernetes distinguishes between Guaranteed, Burstable, and BestEffort. By choosing the right QoS class, unimportant pods can use cheap resources while critical apps remain protected.

17. What is a “Unit Metric” in FinOps? A business metric that is related to cloud costs, e.g., “cost per 1,000 invoices generated.” If costs rise but the unit count rises faster, efficiency has increased.

18. How often should rightsizing recommendations be implemented? Ideally automated or weekly as part of the sprint. Since application behavior changes due to code updates, rightsizing is not a one-time project but an ongoing process.

19. What are the “Crawl, Walk, Run” phases in FinOps? Crawl: Manual reports and visibility. Walk: Initial optimizations and team responsibility. Run: Fully automated scaling, real-time cost attribution, and precise forecasts.

20. Why is a central FinOps team beneficial? It consolidates knowledge about provider discounts (Reserved Instances, Savings Plans) and supports decentralized engineering teams with the right tools and best practices.

FinOps in Kubernetes - 20 Answers