---
title: Automatic rolling of Pods due to configuration changes
url: https://devopstales.github.io/kubernetes/k8s-rolling-upgrade/
date: 2023-05-29
keywords: Kubernetes Scheduler, Deployment controller, Rolling Update, Rolling Upgrade, Config change
---


In this post I will show you how you can for pod upgrade at config changes in helm charts.
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Alongside the deployment of containers, we often ship configuration via `ConfigMap` and/or `Secret` resources. A common challenge is the need to restart the `Pod` resources when there is a change in the associated configuration.

By default, if the `Pod` itself didn’t change, the `Deployment` or `StatefulSet` resource will not trigger a new rollout.

### Roll when Secret or ConfigMap resources changes

So to rol the Pod we need to change something in the spec when the config is changing. But what? and how to realize the change of the `ConfigMap` and/or `Secret`? The solution is to store the checksum of the  `ConfigMap` and/or `Secret` in the annotation of the Deployment, so when the file is changing the checksum is changing too, and with this we gat a new version from the `Deployment`.

```yaml
kind: Deployment
[...]
spec:
  template:
    metadata:
      annotations:
        checksum/config: {{ include (print $.Template.BasePath "/configmap.yaml") . | sha256sum }}
[...]
```

For resources defined as part of a `library` chart:

```yaml
kind: Deployment
[...]
spec:
  template:
    metadata:
      annotations:
        checksum/config: {{ include ("mylibchart.configmap") . | sha256sum }}
[...]
```