Client authentication against a reference OpenStack installation requires the following.

1. Create an instance of CloudIdentityWithProject and initialize its properties with the desired authentication credentials. The CloudIdentityWithProject credentials class allows the tenantName and tenantId properties described in the OpenStack documentation to be defined.

2. Create an instance of OpenStackIdentityProvider, and pass the previously created credentials to the constructor.

3. When creating a service provider instance, such as CloudFilesProvider or CloudQueuesProvider, pass null for the CloudIdentity parameter and the identity provider from the previous step as the IIdentityProvider parameter.

The OpenStackIdentityProvider only supports authentication using username and password credentials, along with optionally specifying the tenant name and/or tenant ID (referred to as the project name and ID starting with the Identity Service API v3).

Reference