> For the complete documentation index, see [llms.txt](https://platform9.com/kb/llms.txt). Markdown versions of documentation pages are available by appending `.md` to page URLs; this page is available as [Markdown](https://platform9.com/kb/pmk/how-to/replica-of-coredns-pod-being-scaled-down-continuous.md).

# CoreDNS Pod Replica Gets Continuously Scaled Down by the Deployment-Controller

## Problem

* One replica of the ***CoreDNS*** **pod** is getting scaled down continuously by the ***Deployment-Controller*** and the ***Kube-DNS***\_\_\_\_\_**Autoscaler**\_ scaling up the replica at the same time.

{% tabs %}
{% tab title="Replica Set" %}

```c
NewReplicaSet: coredns-8dd49b79d (2/2 replicas created) Events: Type Reason Age From Message ---- ------ ---- ---- ------- Normal ScalingReplicaSet 3m1s (x698 over 2d10h) deployment-controller Scaled down replica set coredns-8dd49b79d to 1
```

{% endtab %}
{% endtabs %}

* ***Kube-DNS***\_\_\_\_\_**Autoscaler**\_ keep scaling the replica back up to 2

{% tabs %}
{% tab title="Kube-DNSAutoscaler" %}

```javascript
I0614 15:10:50.259106 1 k8sclient.go:272] Cluster status: SchedulableNodes[6], SchedulableCores[360] I0614 15:10:50.259140 1 k8sclient.go:273] Replicas are not as expected: updating replicas from 1 to 2
```

{% endtab %}
{% endtabs %}

## Environment

* Platform9 Managed Kubernetes - v5.6.4 and Higher.

## Cause

* This is as expected from an ***AutoScaler*** perspective because `**preventSinglePointFailure**` is default set to true.

{% tabs %}
{% tab title="Autoscaler default value" %}

```javascript
{ "coresPerReplica": 256, "nodesPerReplica": 16, "min": 1, "max": 10, "preventSinglePointFailure": true, "includeUnschedulableNodes": true }
```

{% endtab %}
{% endtabs %}

* The ***Addon-Operator*** show the log that it was updating the ***CoreDNS-Addon*** continuously.

{% tabs %}
{% tab title="Addon operator log" %}

```javascript
{"level":"info","msg":"Applying ConfigMap name: coredns (namespace: kube-system, api: v1)","time":"2023-06-14T15:20:22Z"} {"level":"info","msg":"No change from existing state (/v1, Kind=ConfigMap) kube-system/coredns","time":"2023-06-14T15:20:22Z"} {"level":"info","msg":"Applying Deployment name: coredns (namespace: kube-system, api: apps/v1)","time":"2023-06-14T15:20:22Z"} {"level":"info","msg":"Update was successful","time":"2023-06-14T15:20:22Z"} ........... {"level":"info","msg":"Installed pkg: 1c4f2564-f433-4177-93e2-8d56521b46be-coredns-1.8.6","time":"2023-06-14T15:20:22Z"} {"level":"info","msg":"Updating finalizer for addon: 1c4f2564-f433-4177-93e2-8d56521b46be-coredns","time":"2023-06-14T15:20:22Z"} {"level":"info","msg":"Adding finalizer for addon: 1c4f2564-f433-4177-93e2-8d56521b46be-coredns","time":"2023-06-14T15:20:22Z"} {"level":"info","msg":"Updated addon: 1c4f2564-f433-4177-93e2-8d56521b46be-coredns","time":"2023-06-14T15:20:22Z"} {"level":"info","msg":"Ignoring reconcile due to previous status update: 1c4f2564-f433-4177-93e2-8d56521b46be-coredns","time":"2023-06-14T15:20:22Z"} {"level":"info","msg":"Watch: Addon 1c4f2564-f433-4177-93e2-8d56521b46be-coredns converged after triggering it","time":"2023-06-14T15:20:27Z"}
```

{% endtab %}
{% endtabs %}

* Users may also see ***DNS*** resolution failures.

## Resolution

* This issue has been fixed in **PMK v5.9.1**. Upgrade the environment to **v5.9.1+** to fix the issue.


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