In this guide we show how to customize your cluster installation, i.e. if you want to install additional applications, or change the configuration of extisting apps installed by OAS this is the right place. Customizing other parts of your cluster is possible but not yet covered by this guide. This guide is written for users with advanced knowledge of the tools behind Openappstack, most importantly: Kubernetes, Helm, Ansible and Flux 2.


Customizing your OAS cluster could break your cluster in a way that it’s not easy to recover. Please be aware of the potential risk when proceeding.


Customize OAS applications

Apps deployed by OAS are configured using helm values from templates in flux2/apps/<application>/release.yaml. It is possible to override values from the helmrelease by adding a custom ConfigMap or Secret to the cluster. The secret or configmap name is specified in the valuesFrom section of the release.yaml file. Read more in the Flux documentation

Example: Customize Nextcloud to work with staging certificates

Our CI pipeline works with staging certificates from Let’s Encrypt, for that reason we need to allow insecure connections for the integration with ONLYOFFICE. You can find the file at install/overrides/oas-nextcloud-override.yaml.

To apply it, run the following commands:

# If you want to run this on your provisioning machine, tell kubectl to use
# your cluster:
export KUBECONFIG=$PWD/clusters/
# Check the current state of the helmrelease you want to modify:
flux get helmrelease -A
# If all is OK, make sure to apply your override configmap or secret in the
# same namespace as your helmrelease with the '-n' argument
kubectl apply \
  -n oas-apps \
  -f ./install/overrides/oas-nextcloud-override.yaml

Adding custom apps to the cluster

OpenAppStack uses Flux 2 to install and auto-update applications. If you want to install extra applications or other things into the Kubernetes cluster, our advice would be to set up your own GitRepository and add it to the Flux system.

When you do this, you are fully responsible for keeping those applications secure and updated. If any of those applications is insecure, that can also invalidate the security of your OpenAppStack applications, because they are part of the same cluster and VPS.

Refer to the Flux 2 documentation for more information.