That’s a common problem. We solved it by using Chef, which we have setup to detect which drives are mounted/used for OS and which are used for Aerospike directly - then we sort by serial and ‘hand out’ the drives to write the config file and other scripts.
This might be worth looking at, but I’m not sure if it works in AWS. How to configure storage device to use the disk WWID you should probably test first by taking note of the wwid of the disks before a full stop and see if they still appear as same wwid after start… Another thing I’m unsure of in this situation is if the WWID will change if the instance migrates to a new physical host - perhaps AWS support might help? Anyway, to reiterate, the way we solve it is by just excluding anything that is mounted while chef runs before starting up Aerospike. After a stop/start the ephemeral disks are empty anyway, so its fine if it chooses a new order and we don’t care about namespace mixing since they’re all empty.
If you’re using EBS volumes, oof, you probably will only need to do the WWID thing once per EBS vol unless it has to be recreated for some reason.