---
name: containers-ts-network-iks-coredns-restart
title: Why does DNS resolution fail when CoreDNS pods are restarted?
description: '[Virtual Private Cloud] [Classic infrastructure]'
last-updated: 2026-04-08
---

> ## Documentation Index
> The table of contents for this documentation set is at https://cloud.ibm.com/docs/containers?format=markdown
> The index for all IBM Cloud docs is at: https://cloud.ibm.com/docs/llms.txt
> Use these files to discover more information as needed.

# Why does DNS resolution fail when CoreDNS pods are restarted?
{: #coredns_lameduck}
{: support}

[Virtual Private Cloud]{: tag-vpc} [Classic infrastructure]{: tag-classic-inf}


Your app sometimes fails to resolve DNS names for cluster services around the same time that one or more CoreDNS pods are restarted, such as during a worker reload or patch update.
{: tsSymptoms}


Your app's DNS request was sent to a CoreDNS pod that was in the process of terminating.
{: tsCauses}


To help the CoreDNS pods terminate without disruption, you can edit the `coredns` configmap in the `kube-system` namespace.
{: tsResolve}

In the `health` plug-in configuration of the main Corefile, add `lameduck 10s`. For more information on customizing CoreDNS, see [Customizing the cluster DNS provider](https://cloud.ibm.com/docs/containers?topic=containers-cluster_dns&format=markdown#dns_customize). The resulting customization looks like the following example.

```txt
health {
    lameduck 10s
}
```
{: screen}