Yep, we use the integrated vault backend.

In our case, we use lets encrypt to get certificates for vault and then bootstrap a vault cluster with internal storage. Then you have vault and you can use terraform to configure a consul TLS backend.

And then there is a little hitch, because consul-template cannot easily create multiple files from a single vault API call, so you cannot use consul-template directly to create the necessary certificate files. We've written a small messy tool there. But once you have that, it's fairly straight forward to generate consul + nomad TLS certs for the trust and then you're set.

So I actually do this today, and I use Vault. This sounds weird, but I spin up a "bootstrap PKI" Vault that is local-only, and produces, e.g.: "consul.service.dc.consul" certs with the issuer labeled as "bootstrap PKI intermediate" or some such. I generate a full suite of these for everything in a space, get it all up and running, then there's a 2nd layer of automation where self-certs are issued.

That said, I'm moving to a central distributed Vault that is mostly going to exist as a PKI so I'll only really need to repeat this process once more! Going to be using the raft internal engine for this one, and spread it physically across the globe so performance is going to be pretty terrible by design, but it should be quite resilient!