Move disk-usage-alert to postfix_mandrill role.
README.
Reusing the ganglia roles was difficult in non-hadoop setups, fixed. Zookeepers are actually slaves, not masters. Update the apt cache before safe package upgrade.
Force install postgresql, it kept failing due to a warning prompt when I ran it.
Match real and ansible hostnames when bootstrapping fresh EC2 instances.

This changed the box hostnames from e.g. ip-<private-ip> to hslave01. Other
roles and plays seem to assume this is how things are set-up anyway, which is
not true of bog-standard machines from EC2.

Ansible v1.4 now required, since I use the new ‘hostname’ action.
Merge pull request #3 from amirhhz/match-hostnames

Match real and ansible hostnames when bootstrapping fresh EC2 instances.
Merge pull request #4 from amirhhz/force-postgresql

Force install postgresql
Add link to ubuntu-netboot-tftp.
Remove the safe upgrade. It fails with td-agent and it's too dangerous to run by default since it can break user's Hadoop installations.
Initial go at getting travis to deploy to DO.
Travis debugging.
Travis debugging.
Travis debugging.
Travis debugging.
Travis debugging.
Travis debugging.
Travis debugging.
Travis debugging. Fully functional it seems!
Fix destroy DO instances.
Reduce required nodes to 6+1.