How do you clean a juju disk or make it larger?

[Daniel Bidwell]

My juju controllers appear to be defaulting to a 10GB root disk. I am
running out of disk space on the controller. I have 6.7GB in
/var/lib/juju/db. Is there a way to reduce the disk usage on this? If
not, can I make the root disk larger? What are my options?

I have already cleared out kernel updates.
-- 
Daniel Bidwell <drbidwell at gmail.com>