Explicit private/public nature of `*ip` vars (#10904)

docs/vars.md

@@ -34,10 +34,10 @@ Some variables of note include:
 
 ## Addressing variables
 
-* *ip* - IP to use for binding services (host var)
+* *ip* - IP to use for binding services (host var). This would **usually** be the public ip.
 * *access_ip* - IP for other hosts to use to connect to. Often required when
   deploying from a cloud, such as OpenStack or GCE and you have separate
-  public/floating and private IPs.
+  public/floating and private IPs. This would **usually** be the private ip.
 * *ansible_default_ipv4.address* - Not Kubespray-specific, but it is used if ip
   and access_ip are undefined
 * *ip6* - IPv6 address to use for binding services. (host var)