Controller

See also: How to manage controllers

In software design, a controller is an architectural component responsible for managing the flow of data and interactions within a system, and for mediating between different parts of the system. In Juju, it is defined in the same way, with the mention that:

• It is set up via the boostrap process.

• It refers to the initial controller unit as well as any units added later on (for machine clouds, for the purpose of high-availability).

• It is responsible for implementing all the changes defined by a Juju user via a Juju client post-bootstrap.

• It stores state in an internal MongoDB database.