Recently, some external dependency broke nodepool's ability to launch VMs on an openstack provider.
If you haven't run into this yet, it's probably because you haven't restarted nodepool.
When you do, you might get an error similar to 
I couldn't find the issue, but regardless, there's a fix to nodepool that's been merged .
However, you do need to update your nodepool.yaml configurations to use 'project-name' instead of 'project-id'.
Here's an example 
I don't know the solution if you're using cloud.yaml, but it should be similar.
OpenStack Development Mailing List (not for usage questions)