Optionally mount storage as non-root user and group

[Ian M. Jones]

I have a charm that currently runs a daemon as a specific user.

The daemon writes out config files that could be shared across a cluster. Using juju storage for this would be ideal, especially as the shared config includes certificates etc that should not diverge across units of the app.

However, from what I can see, if I specify storage of type “filesystem”, it’s always owned by root/root and the daemon would not be able to write to it.

I have yet to try adding storage of type "block", but I assume it too is mounted as root.

Rather than run the daemon as root, it would be very useful if juju had an option to mount the storage with a specific user/group ownership so that a daemon running as a non-root user could write to the path.

Original discussion: https://discourse.charmhub.io/t/can-storage-be-mounted-with-specific-user-group-ownership/