Support TLS authentication to HashiCorp Vault secrets

We have a customer that recently attempted to use mTLS configuration for their HashiCorp Vault when using it as a backend for Spring Cloud Services (SCS) Config Server. Here is what they provided as information about the attempted configuration:

Here is a link to cert auth at Vault:

https://www.vaultproject.io/docs/auth/cert.html

The bottom of the page has the link to the API.

I have gone through most of the process but am having MTLS issues as our dev vault instance currently has a self-signed cert.  Disabling the check also essentially disables the MTLS handshake.  The internal Vault team is going through the process right now to install a real cert.  They say they can successfully get tokens from Cert auth.

We don't currently support this option that I know of (please let me know if I'm incorrect?). Could we add configuration options that would setup the mTLS handshake and then Config Server would be able to access the Vault API once authorized?

Start by locating the Config Server Vault backend and its existing connection configuration, then review the Vault cert-auth API linked in the issue. Done means configurable client certificates and trust settings establish the requested mTLS connection to the Vault API, including the self-signed-certificate case.