Volumes

Configuring volumes at runtime

Acorn images can define volumes. To see which volumes are available for an Acorn image you can run --help on the image.

acorn run [IMAGE] --help
# ...
Volumes: my-data

The Volumes line shows the volumes that will be created as part of the Acorn app deployment. Unless otherwise specified in the Acorn image and if no default volume class is specified, each volume will be created using the following default values:

Field	Default Value
size	10G
class	default
accessMode	readWriteOnce

These values can be customized at runtime by passing -v arguments. For example, the following command will cause the "my-data" volume to be created with 5G of storage and using the fast volume class:

acorn run -v my-data,size=5G,class=fast [IMAGE]

The volume class used, including the default, may have restrictions on the size of volumes created or the access modes available. If your volume uses a class that is not available or uses class settings that violate its rules, then will not run. A descriptive error will be produced to explain any failures.

You can see a list of available volume classes and their restrictions, if any, with the acorn offerings volumeclasses command.

Using precreated volumes

You can use a precreated volumes by binding the volume at runtime.

acorn run -v db-data:my-data [IMAGE]

This Acorn app will use the volume named db-data as its my-data volume.

The volume will match the size and class of the pre-created PV db-data.