Charms define how services are to be deployed and integrated and how they react to events. Juju orchestrates all of this based on the instructions in charms. Charms are created using plain text metadata files. These files, with the extension .yaml, describe the details needed for deployment. These are the supported fields in a charm:
name—The name of the charm.
summary—A one line description.
maintainer—This must include an email address ...