Defining node classes (functional roles)

Nodes must be configured to belong to a single class, although that class can be a derived subclass. Class names are completely arbitrary. oneSIS defines the class a node belongs to based solely on the node's hostname.

Node classes can be defined by perl-style regular expressions or by using a syntax to describe range expressions. A combination of multiple NODECLASS* directives can be used to describe a single class. For nodes with more than one matching NODECLASS* directive, but different class names, later directives will override earlier ones.

A classname may also be passed in on the kernel command line vie the classname$=$ parameter. This can be used to set or override the oneSIS class for the given node.

Once a class is defined, the class name can be used in other directives to define behavior specific to that class.