The backup files that get downloaded to the local client by means of the `create-backup` command should, by default, reflect the name of the corresponding controller. Otherwise, backups made on multi-controller setups become indistinguishable. Below, there are two backups for a controller named 'lxd' and one for a controller named 'aws':
-rw-rw-r-- 1 ubuntu ubuntu 56M May 15 19:20 juju-backup-20180515-191942.tar.gz
-rw-rw-r-- 1 ubuntu ubuntu 56M May 15 19:40 juju-backup-20180515-193724.tar.gz
-rw-rw-r-- 1 ubuntu ubuntu 56M May 15 19:58 juju-backup-20180515-195557.tar.gz
The user should not have to rely on the `--filename` option to overcome this confusion. I would expect to see, by default:
-rw-rw-r-- 1 ubuntu ubuntu 56M May 15 19:20 juju-backup-aws-20180515-191942.tar.gz
-rw-rw-r-- 1 ubuntu ubuntu 56M May 15 19:40 juju-backup-lxd-20180515-193724.tar.gz
-rw-rw-r-- 1 ubuntu ubuntu 56M May 15 19:58 juju-backup-lxd-20180515-195557.tar.gz
+1, I think that the name should include the controller name, the cloud, and the juju version in the backup file path. I'd not worry about the "juju" part since the it should be clear enough.
jaas-aws-