I view Ansible and Terraform as complementary tools; I can imagine performing rolling upgrades by using Ansible to shoot down a node and then have Terraform reb

I view Ansible and Terraform as complementary tools; I can imagine performing rolling upgrades by using Ansible to shoot down a node and then have Terraform rebuild it; and Terraform could use Ansible to configure the nodes, if you're not using images. For smaller systems one could use Ansible to create the infrastructure too, but I don't think it scales very well.