> For the complete documentation index, see [llms.txt](https://docs.ionos.com/cloud/llms.txt). Markdown versions of documentation pages are available by appending `.md` to page URLs; this page is available as [Markdown](https://docs.ionos.com/cloud/containers/managed-kubernetes/use-cases/add-custom-core-dns-config.md).

# Add Custom CoreDNS Configuration

Add custom CoreDNS configuration in IONOS CLOUD Managed Kubernetes: extend CoreDNS with a ConfigMap to persist changes across control plane maintenance.

It is desirable to extend CoreDNS with additional configuration to make changes that survive control plane maintenance. It is possible to create a ConfigMap in the `kube-system` namespace. The ConfigMap must be named `coredns-additional-conf` and contain a data entry with the key `extra.conf`. The value of the entry must be a string containing the additional configuration.

The following example shows how to add a custom DNS entry for `example.abc`:

```yaml
apiVersion: v1
kind: ConfigMap
metadata:
  name: coredns-additional-conf
  namespace: kube-system
data:
    extra.conf: |
      example.abc:53 {
        hosts {
          1.2.3.4 example.abc
          2.3.4.5 server.example.abc
          fallthrough
        }
      }
```


---

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