Kubernetes scheduler
The Kubernetes scheduler is a control-plane component that assigns unscheduled Pods to suitable nodes according to resource requirements and scheduling constraints.
Acing the Certified Kubernetes Administrator Exam, Second Edition
The Kubernetes control-plane component that selects suitable nodes for running pods according to resources and placement rules.
- How it is used
- Assigns application pods to nodes and guides node-placement tasks and Pending-pod troubleshooting.
- How deep it goes
- Explains resource-aware placement through a node-selector exercise and failure diagnosis, without detailing the scheduler’s selection algorithm.
- Examples
- Uses an SSD-labeled worker-node exercise and a scaled Deployment whose new pods remain Pending after scheduler failure.
- What you can do after
- Practice/perform label-based pod placement, verify the assigned node with kubectl, and diagnose scheduler failures using logs and manifests.
Google Anthos in Action
The Kubernetes scheduler selects suitable nodes for newly created pods according to resource availability and scheduling constraints.
- How it is used
- Explains how Kubernetes places Pods on worker nodes and how deployments constrain that placement.
- How deep it goes
- Describes API-server interaction, node filtering, scoring, and failure conditions, but defers custom-scheduler implementation.
- Examples
- Uses an nginx Pod manifest naming custom-scheduler1 and discusses unschedulable Pods caused by unmet resources or constraints.
- What you can do after
- Operate/configure workloads with selectors, affinity, taints, tolerations, anti-affinity, or a named custom scheduler.
Read how Google Anthos in Action explains Kubernetes scheduler →
Related concepts
- affinityused by · Node affinity is a Kubernetes scheduling constraint that requires or prefers placing a pod on nodes whose labels match specified expressions.
- resource requestused by · A resource request is a Kubernetes container setting that specifies the amount of compute or memory resource required for scheduling and resource accounting.
- static podcontrasts with · A static pod is a Kubernetes pod created and managed directly by the kubelet from a local manifest rather than scheduled by the Kubernetes scheduler.
- control plane nodepart of · A control plane node is a Kubernetes cluster machine that hosts components managing cluster state, exposing the cluster API, scheduling workloads, and coordinating operations.
- schedulerkind of · A scheduler is a system component that selects, orders, dispatches, or assigns execution resources to tasks according to timing, dependency, placement, or other scheduling criteria.
- kube-scheduler.yamlconfigured by · A Kubernetes static-pod manifest that configures the scheduler process and its referenced settings and credentials.
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