Diegolden

Topic 1: kube-scheduler

2 min read

Topic 1: kube-scheduler

Official baseline: (The Kubernetes Authors, 2026). My working version: The scheduler picks a node for Pods that do not already have one. It filters impossible nodes and scores the rest.

Mental Model

The scheduler picks a node for Pods that do not already have one. It filters impossible nodes and scores the rest.

Notes

  • Pending Pods are scheduling evidence, not just failed deployments.
  • Resource requests, node selectors, affinities, taints, and volumes all constrain placement.
  • Scheduler decisions are only as good as the constraints you declare.

Homelab Angle

Practice reading kubectl describe pod events until pending states feel mechanical.

Verify It

  • Read the object status before changing the manifest.
  • Check events for the controller or node that is actually complaining.
  • Confirm the official source linked below still matches the cluster version you run.

Common Failure Modes

  • Treating the YAML object as the system, instead of one input to a reconciliation loop.
  • Debugging from outside the cluster when the failure only exists inside cluster networking or node state.
  • Forgetting that Kubernetes version, addon version, and runtime behavior are linked.

Sources

  • Kubernetes Scheduler - source path: content/en/docs/concepts/scheduling-eviction/kube-scheduler.md, commit 8cc9e19b8eec8d5cf49eacd66f86a81648edb1a0.
  • Kubernetes documentation is licensed under CC BY 4.0; these notes are original commentary and link back to the official source.
The Kubernetes Authors. (2026). Kubernetes Scheduler. https://kubernetes.io/docs/concepts/scheduling-eviction/kube-scheduler/

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