What happened was about a month ago, I created a new instance, re-configured everything, and mounted the old instances drive to the new one. I then detached the old drive from the instance, but it was still mounted, so it errored out. Now, come the outage last month, and when the instance boots back up - the drive isn't there, because in the downtime, it dismounted. It hangs because the fstab is looking for it. I get word that the server's not up today, I check the logs, re-attach the drive and restart. Now I'm getting "Waiting for network configuration..." and it doesn't seem to be doing anything. Some googling told me that I'm going to need to start from zero again, which I don't think is right.
I created a new instance, which booted no problem, then I stopped it and swapped the two old drives into the new instance. Still the same error. Using the fresh AMI, it worked.
I figure it's just a misconfigured Amazon file. I can attach the drive to a functioning instance on the same AMI and copy some files over, then try again - but I don't know where to even start or what files to check.