Topology key
A topology key is a Kubernetes node-label key whose values define the topology domains used to constrain or spread workload placement.
Google Anthos in Action
A topology key is a Kubernetes pod-affinity field that identifies the node-label domain, such as a hostname or zone, used for comparing placement.
- How it is used
- Defines the node-label domain for comparing placement under Pod affinity and anti-affinity rules.
- How deep it goes
- Explains the field through required hostname affinity and preferred zone anti-affinity, without detailing scheduler internals.
- Examples
- Uses a per-node software license and manifests with hostname and zone topology keys.
- What you can do after
- Operate/configure it to group matching Pods on one node or prefer separation across zones.
Kubernetes for Developers
A topology key is a node-label key whose values define the topology domains considered equivalent for spreading workloads.
- How it is used
- Defines equivalent topology domains for spreading workload Pods across nodes.
- How deep it goes
- Explains node-level placement, label verification, imbalance limits, and unsatisfied-constraint behavior.
- Examples
- Uses kubernetes.io/hostname in a three-replica timeserver Deployment and verifies placement with kubectl.
- What you can do after
- Configure node-level workload spreading and verify the required node labels before deployment.
Related concepts
- anti-affinityused by · Anti-affinity is a scheduling constraint that discourages or prevents selected workloads from sharing a node or topology domain with matching workloads.
- spread topologyconfigures · A spread topology is a scheduling constraint that distributes Pods across specified topology domains such as zones or nodes.
- affinitypart of · Node affinity is a Kubernetes scheduling constraint that requires or prefers placing a pod on nodes whose labels match specified expressions.
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