CoreDNS Pod Anti-Affinity Violations

warning

reliabilityUpdated Jan 19, 2026

Multiple CoreDNS pods scheduled on the same node create single points of failure and uneven query load distribution, reducing reliability and causing localized performance issues.

Sources

How to Troubleshoot Kubernetes DNS Issues (CoreDNS) - OneUptimeoneuptime.com

Technologies:

CoreDNSSymptoms of this issue are visible in CoreDNS metrics and logs

KubernetesThe root cause of this issue originates in Kubernetes

How to detect:

Verify CoreDNS pod distribution across nodes using kubectl get pods -n kube-system -l k8s-app=kube-dns -o wide. Alert if multiple CoreDNS pods are co-located on the same node. Monitor per-node query distribution for imbalance.

Recommended action:

Configure pod anti-affinity in CoreDNS deployment to spread replicas across nodes. Use preferredDuringSchedulingIgnoredDuringExecution with topologyKey kubernetes.io/hostname. Increase CoreDNS replicas to match or exceed number of nodes for clusters with 50+ nodes. Monitor pod distribution after each scaling event.