Eestr stands for Ec2 -> Ebs -> Snapshot Tag Replicator.
EBS and Snapshots are usually not tagged when an EC2 instance are created. Eestr is a Lambda function which ensure EBSs and Snapshots are tagged with the same than its corresponding EC2 instance
By now, this function has been tested with Ec2FullAccess Managed Policy (don't kill me yet, plz!). More fine grained permissions will be added in a near future.