Bases¶
A charm runs on a baseline software system, known as its base. The systems are most commonly Ubuntu releases.
The base is declared in the project file by the
base or platforms keys.
LTS and interim bases¶
Ubuntu bases are divided into LTS and interim bases. An LTS base contains an Ubuntu LTS release and has a 10-year support window. An interim base contains an interim Ubuntu release and is supported for nine months.
Interim bases have shorter lifespans and contain upcoming or experimental features. For charms, they are most suitable for compatibility testing for the next Ubuntu LTS release. As such, they have special limitations:
Between minor releases of Charmcraft, repacking a charm might produce differences in the artifact because of changes to the charmcraft.yaml schema. These differences are an accurate preview of how Charmcraft will pack the project in the next Ubuntu LTS release.
The
build-basekey is mandatory.