The Bitbucket AMI has a block device mapping for /dev/xvdf containing an empty 100 GByte EBS volume. It should be possible to simply specify a snapshot ID for this block device mapping when launching the instance, to get a new instance with the same data.

Unfortunately simply specifying a snapshot ID in the AWS Console or CLI does not work. The error is: "Launch failed: snapshotId can only be modified on EBS devices". This is due to a bug in AWS reported in AWS support case number 1370496281.

Workaround

See https://confluence.atlassian.com/bitbucketserver/launching-bitbucket-server-in-aws-manually-776640204.html#LaunchingBitbucketServerinAWSmanually-Addstorage. "To attach an existing EBS volume, within the Device field, change the EBS volume device to /dev/sdf and enter the Snapshot ID of the snapshot."