It appears the clustername that is passed through to ds2_configure.py, ends up being commented out and unused.

Example scylla config after ds2_configure.py has completed:

# The name of the cluster. This is mainly used to prevent machines in
# one logical cluster from joining another.
# It is recommended to change the default value when creating a new cluster.
# You can NOT modify this value for an existing cluster
#cluster_name: example_cluster_name

From the system table:
 cluster_name | host_id
--------------+--------------------------------------
              | 257865d9-446f-42d3-a362-3a714a29806d

The worrisome part is there is no failure, and my cluster ends up starting up fine, and had I not been fighting with getting the ec2snitch to work ( Restrictive Security groups ), I would not have been looking.

I believe we just need to ensure that # is replaced. I will put up a PR shortly. But I wanted to make sure there was no sane reason to leave it alone.