How to create a self-signed certificate request for a domain and all its subdomains with OpenSSL.
The certificate.conf can be used to create a configuration for a certificate. Its content can look as follows:
[req]
default_bits = 2048
default_md = sha256
prompt = no # configuration for openssl command to not prompt, it will take req_distinguished_name instead
distinguished_name = req_distinguished_name # the information required to generate a self-signed certificate