There were once a lot of things in this file: https://gerrit.wikimedia.org/r/plugins/gitiles/operations/puppet/+/refs/heads/production/modules/toollabs/templates/hosts.erb

Now it appears that it only exists to ensure that tools-redis has a name and that we can never leave ubuntu.

Please move the redis names into DNS and add a more consistent redis.svc.eqiad.wmflabs name in there as well.