Create a simple CoreOS cluster on 4 machines

I'd like to try out coreos on our little cluster (4 machines). I’d like to install coreos on each machine’s disk.

I’ve got a trusty64 live cd that I will use to run the coreos-install script. Is there a default cloud-config file I could use to set this up ?

I want to give each machine the private ip 192.168.5.i

Would this file be enough to init my cluster when installing coreos on disk on my first machine (192.168.5.1) ? http://pastie.org/private/njub0e4nahb10enh9nnw

#cloud-config
ssh_authorized_keys:
  - ssh-rsa MYKEY
coreos:
  etcd:
    discovery: https://discovery.etcd.io/MYTOKEN
    addr: 192.168.5.1:4001
    peer-addr: 192.168.5.1:7001
  fleet:
    public-ip: 192.168.5.1
  units:
    - name: etcd.service
      command: start
    - name: fleet.service
      command: start

Seems like when installing on disk $private_ipv4 is not interpreted (do I have to enter the ip then ?)