When running CloudFormation, all the resources are being created with no problem. However it seems to be getting stuck at creating or mounting a volume. The CloudFormation fails and initiates a rollback. This is the error I am getting.

Volume attachment between volume-id vol-xxxxxxxx and instance-id i-xxxxxxx at device /dev/xvda is attaching

This turned out to be a conflict on HVM EC2 instances because /dev/sda1 is being remapped to /dev/xvda. My second drive is also mapped to /dev/xvda. The fix was to simply to map it slightly different to avoid mapping conflict.

Here’s the original mapping.

Boot:   /dev/xvda
Device: /dev/xvda
Device: /dev/xvdb

Here’s the fix.

Boot:   /dev/xvda
Device: /dev/xvdb
Device: /dev/xvdc