Comment 1 for bug 1638704

There was a recent change to do API version discovery. In some calls to OpenStack, Juju will look for an API version matching "v2", which will list all of the available API versions and select the most recent one matching the major version 2. The v2.1 comes from the version list endpoint (GET https://<hostname>:8774/).

It looks like your version of OpenStack supports a microversion >= 2.35, at which point the network API proxy endpoints have been removed. We'll need to update Juju 2.0.x to either force the use of v2.0 (probably simplest), or specify a microversion.

There is work underway to move us off using the deprecated network APIs, and use the Neutron service directly. I think this won't be landing until Juju 2.1.