hostname approach

gistfile1.txt

Here's an approach to ensure at least 2 things are sensible on the host: ${hostname} and ${fqdn} 

if ${hostname} is not specified via api, it could be set to the same as the node's name

in private clouds, ${fqdn} may need to come from a property or a conversion fn (ex. = ${hostname}.mydomain.com)
in public clouds, ${fqdn} can be set via api data (ec2.publicDnsName), dns resolution, or x-x-x-x.static.cloud-ips.com

on (centos|fedora|rhel|amzn_linux)-based operating systems
  /etc/sysconfig/network: replace line HOSTNAME=${fqdn}
  /proc/sys/kernel/hostname: replace w/${fqdn}

on (debian|ubuntu)-based operating systems
  /etc/hostname: replace w/${hostname}
  exec hostname ${hostname}

on all
  /etc/hosts: add or replace line ^127.0.0.1 localhost.localdomain localhost ${hostname}
  /etc/hosts: add or replace line ^${public_ip} ${fqdn} ${hostname}
  /etc/hosts: add or replace line ^${private_ip} ${hostname}

before attempting to run this script, the input data should be checked to ensure it is valid:
ex. run InternetDomainName.isValid on ${fqdn}

A test could be to logon to the machine and make sure ${fqdn} resolves to ${public_ip} and ${hostname} to ${private_ip}

On the yakkier bit, I'm going to quiz openstack-infra a bit about how they handle this for their jenkins stuff right now. They use puppet, which is pretty fqdn sensitive (ssl certificates and all). Maybe there's an option we can make that doesn't presume tools like whirr know about all machines (ex the puppetmaster) who also need to resolve the new nodes.

On the less yakkier bit, I'll start on it tonight :)