This is a very simple sign-signed certificate generator that gives no options except the dns name(s).
package main
import (
"io/ioutil"
"github.com/isaaguilar/selfsigned"
)
func main() {
dnsName := []string{"foo.bar.svc.cluster.local", "foo.bar.svc", "foo.bar"}
selfSignedCert := selfsigned.NewSelfSignedCertOrDie(dnsNames)
ioutil.WriteFile("ca.crt", selfSignedCert.CACert, 0600)
ioutil.WriteFile("tls.crt", selfSignedCert.TLSCert, 0600)
ioutil.WriteFile("tls.key", selfSignedCert.TLSKey, 0600)
}