Node Selector - CI/CD Glossary Definition

A node selector limits a job to runners that carry matching labels.

A node selector is a set of key/value labels that constrains where a job can run, matching it only to runners (or nodes) that carry every required label.

A node selector is the simplest scheduling constraint: it filters candidate runners to those whose labels match, before any affinity or bin-packing decision is made.

In CI

GitHub Actions runs-on labels behave like a node selector: runs-on: [self-hosted, linux, arm64] restricts the job to runners with all three labels.

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