/etc/sysimage.conf centrally manages the behavior of
every node booting into that image. The directives are few and
simple with clear functions. The directives are used to define role
abstractions for all the nodes and express the desired
behavior of each role.
With the exception of the NODECLASS* directives, any directive in the configuration can be overridden by directives further down in the configuration. Additionally, any directive (except for NODECLASS* directives) can be limited to apply to only one or more classes of nodes or to individual nodes.