ressourcerequests

Resource requests are a specification of the minimum compute resources that a workload requires to run. In modern containerized and cloud environments, resource requests inform schedulers about how to place work on available hardware and how much capacity to reserve for each task. They help ensure that workloads have enough resources to operate and that resources are not overcommitted to the point of starvation for other tasks.

In Kubernetes and many orchestration systems, resource requests are defined for each container, typically specifying CPU and memory, and sometimes other resources such as storage or GPUs. The scheduler uses these requests to determine which node can accommodate a pod without exceeding the node’s capacity. The total of all requested resources on a node should be within the node’s allocatable resources to avoid contention.

Resource requests are usually paired with resource limits, which cap the maximum a container may use. If a container’s usage exceeds its limit, it may be throttled or terminated depending on the resource type. If no requests are set, a workload may be classified as BestEffort, and scheduling becomes riskier. The relationship between requests and limits also affects the pod’s Quality of Service class, influencing behavior under pressure.

Beyond Kubernetes, resource requests appear in other scheduling and batch systems such as Hadoop YARN, Apache Mesos, Slurm, and cloud autoscalers. They enable capacity planning, fair sharing, and autoscaling by providing a predictable baseline of resource needs.

Best practices include profiling typical workload usage, setting requests to realistic baselines, and using limits to prevent resource hogging. Regular monitoring and adjustment help maintain efficient and stable cluster operation.