A long while ago I published my solution for automated L3VPN provisioning… and I’m really glad I can point you to a much better one ;)
Håkon Rørvik Aune decided to tackle the same challenge as his hands-on assignment in the Building Network Automation Solutions course and created a nicely-structured and well-documented solution (after creating a playbook that creates network diagrams from OSPF neighbor information).
Want to be able to do something similar? You missed the Spring 2019 online course, but you can get the mentored self-paced version with Expert Subscription.
Thanks to Ivan Pepelnjak (see source)