This demonstrates using Cloudflare's [cfssl](https://github.com/cloudflare/cfssl) to easily generate certificates for an etcd cluster.
Defaults generate an ECDSA-384 root and leaf certificates for `localhost`. etcd nodes will use the same certificates for both sides of mutual authentication, but won't require client certs for non-peer clients.
2. Amend https://github.com/coreos/etcd/blob/master/hack/tls-setup/config/req-csr.json - IP's currently in the config should be replaced/added with IP addresses of each cluster node, please note 127.0.0.1 is always required for loopback purposes: