variables.
1. AWS has issues with ext4 (use xfs instead for CentOS only)
2. Make sure all the centos config files are include in the systemd config
3. Make sure that network options are set in the correct file by os family
This allows downstream items like opencontrail and others change variables
in expected locations.
Each node can have 3 IPs.
1. ansible_default_ip4 - whatever ansible things is the first IPv4 address
usually with the default gw.
2. ip - An address to use on the local node to bind listeners and do local
communication. For example, Vagrant boxes have a first address that is the
NAT bridge and is common for all nodes. The second address/interface should
be used.
3. access_ip - An address to use for node-to-node access. This is assumed to
be used by other nodes to access the node and may not be actually assigned
on the node. For example, AWS public ip that is not assigned to node.
This updates the places addresses are used to use either ip or access_ip and walk
up the list to find an address.
