Support notes

This page describes supportability aspects within the OpenStack Charms project.

Cross model relations

Juju relations that are added between applications that reside in separate Juju models are called Cross model relations (CMR). For a Charmed OpenStack deployment, CMR support must also be present in terms of the manner in which the charms are combined. The OpenStack Charms do not generically support CMR.


It is recommended to exercise each new CMR scenario in a lab environment before committing to that topology in production.

The current list of supported CMR scenarios with regard to OpenStack Charms is as follows:

  1. The keystone application in one model, related to the vault application in a second model.

  2. The ceph-mon application in one model, related to the ceph-rbd-mirror application in a second model. This scenario is documented in Ceph RBD mirroring.

  3. A ceph-radosgw application in one model, related to another ceph-radosgw application in a second model. This scenario is documented in Ceph RADOS Gateway multi-site replication.

Other scenarios may work but are currently not supported. Distinct development and testing efforts are required in order to qualify each unique CMR scenario.

If you would like to help drive the development work towards implementing a supported CMR scenario file a Launchpad bug describing your use case. To assist in this effort kindly use the cross-model bug tag.

Breaking changes between Juju 2.9.x and 3.x

As this guide is written for Juju 3.x, users of 2.9.x will encounter noteworthy changes when following the instructions. This section explains those changes.

Breaking changes have been introduced in the Juju client between versions 2.9.x and 3.x. These are caused by the renaming and re-purposing of several commands - functionality and command options remain unchanged.

In the context of this guide, the pertinent changes are shown here:







run-action --wait


See the Juju 3.0 release notes for the comprehensive list of changes.

The response is to therefore substitute the documented command with the equivalent 2.9.x command. For example:

Juju 3.x,

juju integrate keystone-hacluster:ha keystone:ha

Juju 2.9.x,

juju add-relation keystone-hacluster:ha keystone:ha


Pages in this guide impacted by these name changes have had an admonishment added to them that points back to this present page.