Adding a persistent volume to a Kubernetes deployment from Gitlab Auto Dev-ops
The answer is that all Auto Dev-Ops deployments at present use Helm to package and deploy your application.

In order to make changes to the deployment, such as adding a persistent volume claim, you should download and modify the Helm chart that GitLab uses.

The files in this repo should go into a new directory chart/, or you can link to another location by setting the AUTO_DEVOPS_CHART project variable to a URL.

This page has more details.