expand_volume_en.md

Dogu volumes

Usually, a volume with a default size is created during the installation of a Dogu. The size of the volume is two gigabytes. The dataVolumeSize field can be used to specify a custom size for a volume. However, for some dogus it may be useful to edit the volume size later on.

Increasing the size of volumes

The Dogu CR provides a configuration option for this in the spec attribute:

Example:

spec:
  resources:
    dataVolumeSize: 2Gi

The sizes of the volumes must be specified in binary format (e.g. Mi or Gi).

Setting dataVolumeSize and updating the Dogu resource will start the process to increase the volume size.

Note that the value of dataVolumeSize must match the norm of Kubernetes Quantities.

In Kubernetes, however, a true increase in volume size is only possible if all pods using the volume, are shut down. As a first step, the k8s-dogu-operator scales the deployment of the Dogus to 0 and shuts down all pods of the Dogus shut down. Then the process to scale up the volume starts. The k8s-dogu-operator updates the desired size in the persistentVolumeClaim of the Dogus. Then it waits until the storage controller enlarges the volume and the desired size is reached. After that, the k8s-dogu-operator scales the deployment of the Dogus back to the original number of replicas.

Info

• Enlarging volumes can take several minutes to hours.
• Volumes cannot be scaled down.