---
title: Autoscale the DNS Service in a Cluster
content_type: task
weight: 80
---

<!-- overview -->
This page shows how to enable and configure autoscaling of the DNS service in
your Kubernetes cluster.


## {{% heading "prerequisites" %}}


* {{< include "task-tutorial-prereqs.md" >}} {{< version-check >}}

* This guide assumes your nodes use the AMD64 or Intel 64 CPU architecture.

* Make sure [Kubernetes DNS](/docs/concepts/services-networking/dns-pod-service/) is enabled.



<!-- steps -->

## Determine whether DNS horizontal autoscaling is already enabled {#determining-whether-dns-horizontal-autoscaling-is-already-enabled}

List the {{< glossary_tooltip text="Deployments" term_id="deployment" >}}
in your cluster in the kube-system {{< glossary_tooltip text="namespace" term_id="namespace" >}}:

```shell
kubectl get deployment --namespace=kube-system
```

The output is similar to this:

    NAME                   READY   UP-TO-DATE   AVAILABLE   AGE
    ...
    kube-dns-autoscaler    1/1     1            1           ...
    ...

If you see "kube-dns-autoscaler" in the output, DNS horizontal autoscaling is
already enabled, and you can skip to
[Tuning autoscaling parameters](#tuning-autoscaling-parameters).

## Get the name of your DNS Deployment {#find-scaling-target}

List the DNS deployments in your cluster in the kube-system namespace:

```shell
kubectl get deployment -l k8s-app=kube-dns --namespace=kube-system
```

The output is similar to this:

    NAME      READY   UP-TO-DATE   AVAILABLE   AGE
    ...
    coredns   2/2     2            2           ...
    ...

If you don't see a Deployment for DNS services, you can also look for it by name:

```shell
kubectl get deployment --namespace=kube-system
```

and look for a deployment named `coredns` or `kube-dns`.


Your scale target is

    Deployment/<your-deployment-name>

where `<your-deployment-name>` is the name of your DNS Deployment. For example, if
the name of your Deployment for DNS is coredns, your scale target is Deployment/coredns.

{{< note >}}
CoreDNS is the default DNS service for Kubernetes. CoreDNS sets the label
`k8s-app=kube-dns` so that it can work in clusters that originally used
kube-dns.
{{< /note >}}

## Enable DNS horizontal autoscaling {#enablng-dns-horizontal-autoscaling}

In this section, you create a new Deployment. The Pods in the Deployment run a
container based on the `cluster-proportional-autoscaler-amd64` image.

Create a file named `dns-horizontal-autoscaler.yaml` with this content:

{{% code_sample file="admin/dns/dns-horizontal-autoscaler.yaml" %}}

In the file, replace `<SCALE_TARGET>` with your scale target.

Go to the directory that contains your configuration file, and enter this
command to create the Deployment:

```shell
kubectl apply -f dns-horizontal-autoscaler.yaml
```

The output of a successful command is:

    deployment.apps/kube-dns-autoscaler created

DNS horizontal autoscaling is now enabled.

## Tune DNS autoscaling parameters {#tuning-autoscaling-parameters}

Verify that the kube-dns-autoscaler {{< glossary_tooltip text="ConfigMap" term_id="configmap" >}} exists:

```shell
kubectl get configmap --namespace=kube-system
```

The output is similar to this:

    NAME                  DATA      AGE
    ...
    kube-dns-autoscaler   1         ...
    ...

Modify the data in the ConfigMap:

```shell
kubectl edit configmap kube-dns-autoscaler --namespace=kube-system
```

Look for this line:

```yaml
linear: '{"coresPerReplica":256,"min":1,"nodesPerReplica":16}'
```

Modify the fields according to your needs. The "min" field indicates the