Manage charm resources

When you deploy / update an application from a charm, that automatically deploys / updates any charm resources, using the defaults specified by the charm author. However, you can also specify resources manually (e.g., to try a resource released only to edge or to specify a non-Charmhub resource). This document shows you how.

Specify the resources to be deployed with a charm

To specify the resource(s) to be deployed with your charm, in your Terraform plan, in the definition of the resource for the application specify a resources block with key-value pairs listing resource names and their revision number. For example:

resource "juju_application" "application_one" {
  name = "my-application"
  model_uuid = juju_model.testmodel.uuid

  charm {
    name = "juju-qa-test"
    channel = "2.0/edge"
  }
  resources = {
    "foo-file" = 4
  }
}

Tip

About charm > revision and resources:

  • If you specify only charm > revision: This is equivalent to juju deploy <charm> --revision or juju refresh <charm> --revision – that is, the resource revision is automatically the latest.

  • If you specify only resources: This is equivalent to juju attach-resource – that is, the resource revision is whatever you’ve specified.

Note: While juju refresh <charm> --resource allows you to update a resource even if no update is available for the charm, this is not possible with terraform juju.