Manage relations

Add a relation

Add a same-model relation

To add a same-model relation, create a resource of the juju_integration type, give it a label (below, this), and in its body add:

  • a model attribute specifying the name of the model where you want to create the relation;

  • two application blocks, specifying the names of the applications that you want to integrate (and, if necessary, their endpoints_;

  • a lifecycle block with the replace_triggered_by argument specifying the list of application attributes (always the name, model, constraints, placement, and charm name) for which, if they are changed = destroyed and recreated, the relation must be recreated as well.

Caution

To avoid complications (e.g., race conditions) related to how Terraform works:

Make sure to always specify resources and data sources by reference rather than directly by name.

For example, for a resource / data source of type juju_model with label development and name mymodel, do not specify it as mymodel but rather as juju_model.development.name / data.juju_model.development.name.

resource "juju_integration" "this" {
  model = juju_model.development.name
  via   = "10.0.0.0/24,10.0.1.0/24"

  application {
    name     = juju_application.wordpress.name
    endpoint = "db"
  }

  application {
    name     = juju_application.percona-cluster.name
    endpoint = "server"
  }

  # Add any RequiresReplace schema attributes of
  # an application in this integration to ensure
  # it is recreated if one of the applications
  # is Destroyed and Recreated by terraform. E.G.:
  lifecycle {
    replace_triggered_by = [
      juju_application.wordpress.name,
      juju_application.wordpress.model,
      juju_application.wordpress.constraints,
      juju_application.wordpress.placement,
      juju_application.wordpress.charm.name,
      juju_application.percona-cluster.name,
      juju_application.percona-cluster.model,
      juju_application.percona-cluster.constraints,
      juju_application.percona-cluster.placement,
      juju_application.percona-cluster.charm.name,
    ]
  }
}

Add a cross-model relation

In a cross-model relation there is also an ‘offering’ model and a ‘consuming’ model. The admin of the ‘offering’ model ‘offers’ an application for consumption outside of the model and grants an external user access to it. The user on the ‘consuming’ model can then find an offer to use, consume the offer, and integrate an application on their model with the ‘offer’ via the same integrate command as in the same-model case (just that the offer must be specified in terms of its offer URL or its consume alias). This creates a local proxy for the offer in the consuming model, and the application is subsequently treated as any other application in the model.

Warning

The Juju provider does not currently support the creation of cross-controller relations. A workaround is to use the Juju CLI to create the cross-controller relation.

Remove a relation

To remove a relation, in your Terraform plan, remove its resource definition.