Updates documentation

cloud-config

 #cloud-config
 
+hostname: k1
 coreos:
   update:
     reboot-strategy: best-effort
@@ -15,3 +16,19 @@ write_files:
     owner: root
     content: |
       core@backup.dev
+write_files:
+  - path: /etc/hosts
+    permissions: 0644
+    owner: root
+    content: |
+      127.0.0.1 localhost
+      255.255.255.255 broadcasthost
+      ::1 localhost
+      10.0.0.xx mybackupserver
+      10.0.0.yy myotherserver
+ssh_authorized_keys:
+  - ssh-rsa AAAAB3NzaC1yc2EAAAABIwAAAQEA6NF8iallvQVp22WDkTkyrtvp9eWW6A8YVr+kz4TjGYe7gHzIw+niNltGEFHzD8+v1I2YJ6oXevct1YeS0o9HZyN1Q9qgCgzUFtdOKLv6IedplqoPkcmF0aYet2PkEDo3MlTBckFXPITAMzF8dJSIFo9D8HfdOV0IAdx4O7PtixWKn5y2hMNG0zQPyUecp4pzC6kivAIhyfHilFR61RGL+GPXQ2MWZWFYbAGjyiYJnAmCP3NOTd0jMZEnDkbUvxhMmBYSdETk1rRgm+R4LOzFUGaHqHDLKLX+FIPKcF96hrucXzcWyLbIbEgE98OHlnVYCzRdK8jlqm8tehUc9c9WhQ== vagrant insecure public key
+users:
+  - name: backup
+    ssh-authorized-keys:
+      - ssh-rsa AAAAB3NzaC1yc2EAAAABIwAAAQEA6NF8iallvQVp22WDkTkyrtvp9eWW6A8YVr+kz4TjGYe7gHzIw+niNltGEFHzD8+v1I2YJ6oXevct1YeS0o9HZyN1Q9qgCgzUFtdOKLv6IedplqoPkcmF0aYet2PkEDo3MlTBckFXPITAMzF8dJSIFo9D8HfdOV0IAdx4O7PtixWKn5y2hMNG0zQPyUecp4pzC6kivAIhyfHilFR61RGL+GPXQ2MWZWFYbAGjyiYJnAmCP3NOTd0jMZEnDkbUvxhMmBYSdETk1rRgm+R4LOzFUGaHqHDLKLX+FIPKcF96hrucXzcWyLbIbEgE98OHlnVYCzRdK8jlqm8tehUc9c9WhQ== vagrant insecure public key (this should be ssh key of the root user of the other server)

doc/deploying-a-server.md

@@ -3,9 +3,18 @@
 ## Before you start
 Make sure you read [getting started](getting-started-as-a-hoster.md) first.
 
-### Prepare your orchestration data
-* Get a CoreOS server, for instance from [RackSpace](rackspace.com), [Vultr](vultr.com), or [Hetzner](http://serverboerse.de/).
-* If you prefer another operating system, you can also run our Docker images [using just Docker and bash](using-just-docker-and-bash.md).
+### Prepare your servers
+
+#### with CoreOS
+
+* Get 2 CoreOS server, for instance from [RackSpace](rackspace.com), [Vultr](vultr.com), or [Hetzner](http://serverboerse.de/).
+ * let's call them k1 and k2
+ * they will be backup of each other
+* Modify the cloud-config according to your needs
+ * make sure the backup user get the ssh public key of the root of the other server
+
+#### other linuxes
+* * If you prefer another operating system, you can also run our Docker images [using just Docker and bash](using-just-docker-and-bash.md).
 * If you didn't add your public ssh key during the order process (e.g. through your IaaS control panel or a cloud-config file),
   scp your laptop's public ssh key (probably in `~/.ssh/id_rsa.pub`) to `.ssh/authorized_keys` for the remote user
   you will be ssh-ing and scp-ing as (the default remote user of our deploy scripts is 'core').