Confined snaps cannot write to /var/tmp by design.
But juju-db can write to ~/snap/juju-db/common and /var/snap/juju-db/common/
So you need to mount a filesystem at a mount point under /var/snap/juju-db/common/ and things should work.
Confined snaps cannot write to /var/tmp by design.
But juju-db can write to ~/snap/ juju-db/ common and /var/snap/ juju-db/ common/
So you need to mount a filesystem at a mount point under /var/snap/ juju-db/ common/ and things should work.