cd terraform/

create secret.tfvars file with similar content:

variable_a=aaaa
variable_b=bbb

with not very sesitive parameters, for sensible like passwords, pass them by command line after doing:

terraform apply -var-file="secret.tfvars"

Ansible can use dynamic inventory based on terraform openstack output. In main directory:

ansible-playbook site.yaml

or

ansible-playbook site.yml -i inventories/production