* gRPC API server requires a CA certificate to verify
and authenticate clients (passed via -ca-file)
* gRPC clients must authenticate with a client certificate
and key (passed via -cert-file and -key-file)
* A CA certificate (e.g. ca.crt) should be used to sign a server
certificate (server.crt for a private key server.key)
* gRPC API server requires a server certificate and key to be enabled
(passed via -cert-file and -key-file)
* gRPC client bootcmd tool must verify the server identity using a
known CA (passed to bootcmd via -ca-file)
* This provides transport security, it does not provide client
authentication
