Resource request

As explained in Acing the Certified Kubernetes Administrator Exam, Second Edition

A CPU request is the amount of CPU capacity that a container requires for scheduling and resource-utilization calculations.

A resource request specifies the minimum CPU or memory a pod requires. The scheduler uses these values to place the pod on a node with adequate capacity. section 4.2 section 4.2.1

Apply requests with these Kubernetes configuration rules:

• Define requests under a container's resources field in the pod YAML. section 4.2.1
• Set CPU and memory independently; either request can be omitted. section 4.2.1
• Use requests without limits, or limits without requests; Kubernetes copies limit values into requests when requests are absent. section 4.2.1
• Provide CPU requests before using CPU-utilization targets with the Horizontal Pod Autoscaler, because they establish the utilization baseline. section 5.1.5

Add a CPU request to a Deployment

Generate editable YAML with `kubectl run nginx2 --image=nginx --dry-run=client -o yaml > nginx2.yaml`, then place the request under the container's resources field: `resources:\n requests:\n cpu: 10m`. Apply a Deployment update with `kubectl apply -f deploy.yaml`, and verify the configured request with `kubectl get deploy nginx -o yaml`. section 4.2.1 section 5.1.5

Figure 4.13 Where to insert the resource requests for pods within the pod YAML

Use the YAML placement figure to locate the resources and requests fields inside a pod container specification. section 4.2.1

How Acing the Certified Kubernetes Administrator Exam, Second Edition covers it

How deep it goes

Defines CPU and memory minimums, YAML placement, optional limits, automatic defaults, and HPA baseline behavior.

Examples

Uses nginx YAML, a 10m CPU request, kubectl apply, and kubectl output verification.

What it assumes

Assumes basic Kubernetes pod scheduling and YAML indentation while teaching request and limit configuration explicitly.

What you can do after

Operate/configure pods by editing resource requests, applying YAML with kubectl, and verifying scheduling-related configuration.

How it connects

Connects resource requests with the scheduler, resource limits, pods, Deployments, and the Horizontal Pod Autoscaler.

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Also explained in

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  Kubernetes for DevelopersA resource request is the amount of a particular compute resource that a Kubernetes container is expected to need for scheduling and resource accounting.

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Related concepts

• resource limitcontrasts with · A resource limit is an enforced or configured maximum on the amount or rate of resource consumption or service activity within a specified scope.
• resource overcommitmentused by · Resource overcommitment is allocating or accepting resource demands whose aggregate exceeds available capacity, relying on demands not reaching their peaks simultaneously.
• Kubernetes scheduleruses · The Kubernetes scheduler is a control-plane component that assigns unscheduled Pods to suitable nodes according to resource requirements and scheduling constraints.
• schedulinguses · Scheduling is the planning and coordination of when and in what order activities or computational work occur, potentially assigning them to available resources subject to constraints.
• pod evictionused by · Pod eviction is the removal of a Pod from its node, typically to respond to resource pressure, maintenance, or other cluster-management conditions.
• Kubernetesused by · Kubernetes is an open-source platform for orchestrating and automating the deployment, scaling, and management of containerized workloads across computing clusters.

This explainer was generated by Manning's knowledge graph from the text of Acing the Certified Kubernetes Administrator Exam, Second Edition. The section links point to the parts of the book it draws on.