$ GOPATH/bin/cfssl gencert -initca ca_csr_rsa.json | GOPATH/bin/cfssljson -bare 5min-rsa
$ GOPATH/bin/cfssl gencert -initca ca_csr_ecdsa.json | GOPATH/bin/cfssljson -bare 5min-ecdsa
The above commands will generate 5min-rsa.csr and 5min-ecdsa.csr as well, but those files can be ignored.