I know that the title seems to be completely contradictory, but allow me to elaborate. Reading Bruce Schneier's recent article on data deletion got me thinking that every server should have full-disk encryption, if only for the fact that knowing
rm file securely deletes the file and as long as it's not anywhere else, it's gone forever.
If I found a way to, say, run one "really secure" server which served as the key server for the LUKS filesystem decryption keys and all other servers simply did some kind of net-boot in which they reached out to this "really secure" server for the keys, could I achieve full-automation on these machines? Since I have to assume that Amazon could (if they wanted) easily extract encryption keys, do I realistically lose any security with this setup? By full-automation, I mean being able to add and remove machines at will without any manual intervention on my behalf or physical access. Additionally, machines should be able to restart on their own and not choke waiting for a decryption passphrase.
Also, is this possible? I thought that there was a way to do something like this, but I'm a little hazy on the subject at the moment.