Have a self-signed CA certificate with a longish expiration and sign the actual keys the webservers use with that. Apply TOFU to that CA certificate (on a per-domain basis).
There's IIRC no mechanism for that, but for the single-domain CA key it'd make sense to sign the new one with the old one.
There's IIRC no mechanism for that, but for the single-domain CA key it'd make sense to sign the new one with the old one.