Comment 3 for bug 1674649

I've found the root cause (actually my bad :) ), fix is on review https://review.openstack.org/#/c/449125/

This however highlights a problem with bifrost testing - we basically are only testing roles, but not the playbooks we advise users to use.

Ideally we should should somehow just include the install.yaml (and other playbooks) into the test-bifrost.yaml one to actually test them on gates.