Start with an ebs root based instance to begin with.
I've converted most of mine to these.
I did try to convert some existing ones to ebs only,but after 3 or 4 hours, I found out
I could just re-install all the needed binary packages, and copy across our folks code,data,etc
(the launch instance button),
click the "Viewing" drop-down that defaults to all images and pick EBS images.
Many Fedora,Ubuntu, Amazon-Linux, to pick from. Note: on all these it shows
"Root Device: EBS"...
Boot it with your other choices, certs, region, architecture,etc.
login to it,customize it, fix it up as you see fit.
stop it. NOT TERMINATE
start it again, and everything on root is as you left it.
There are some startup scripts amazon or somebody supplies that re-init /mnt each time,
but I just have separate EBS backups of our base software.
This setup is ideal for us, where we do not have huge load spikes,but instead have
occasional tasks that take 2 x our regular hosts, and so I've got half a dozen instances
that are "STOPPED" and not getting any CPU charges (but they do take up minuscule S3
So this leaves you with permanent root stuff,not transient,and you stop,start,as you
Any of the EBS instances, you can "boot more like this", if you need 20 in a hurry.
Note2: If you attach big EBS volumes, to an EBS based AMI and pick Boot more like this
it makes copies of those attached volumes. and that can take a while to have it boot,
as well as unexpected storage charges with all these funky snapshots laying about.
You can probably do this thru the cli tools also,but I found the console easy enough.