ok, so having read a bit more and done a few tests I have my head around this persistent (s3) and non-persistent (EC2) part. When you use an AMI, it comes with “disk RAM” you can reboot and install to your hearts content, but if it crashes or you shut it down it is GONE, all GONE!!!!
So what does this now leave us with? Well it is a pickle no doubt (matrix reloaded)
Solutions seem to be:
1) Build the image up to what you want and then rebundle it and run that image. (down time!)
2) Install software somehow not tied to the “disk RAM” part of the image (chroot??)
3) run multiple instances and hope they do not both fail
I’ll update later.