Comment 0 for bug 1855179

Added this section to a dummy k8s charm:

storage:
  database:
    type: filesystem
    location: /srv/mysql
  backup:
    type: filesystem
    location: /srv/backup

juju deploy ./<charm-dir> --storage 'database=tmpfs,100M backup=tmpfs,100M'

juju run --unit dummy/0 'storage-add backup=2'

juju status
Model Controller Cloud/Region Version SLA Timestamp
controller microk8s-localhost microk8s/localhost 2.7.0 unsupported 23:25:58+03:00

App Version Status Scale Charm Store Rev OS Address Notes
dummy dummy:7.3 active 0/1 dummy local 0 kubernetes 10.152.183.123

Unit Workload Agent Address Ports Message
dummy/0 active failed 10.1.75.101 80/TCP

application-dummy: 23:23:10 ERROR juju.worker.uniter.context cannot add storage: adding storage backup for unit-dummy-0: adding "backup" storage to dummy/0: cannot attach, storage is singular
application-dummy: 23:23:10 ERROR juju.worker.uniter resolver loop error: executing operation "run action 5": running action "juju-run": cannot add storage: adding storage backup for unit-dummy-0: adding "backup" storage to dummy/0: cannot attach, storage is singular

Resolving a unit does not work because it's not in the error state:

juju resolved dummy/0
ERROR unit "dummy/0" is not in an error state