A host type is distinguished by its name and its attributes. An attribute is a name-value pair.
Host-Type Attribute Characteristics
Each attribute can have a default value.
Attributes names must begin with a letter and cannot include spaces.
Attribute names must be unique within a particular host type.
Adding new attributes to the host type results in the attributes and their defaults being added to every host of that type.
Removing attributes from a host type permanently deletes those attributes from every host of that type.
Attributes cannot be renamed. Attributes can only be deleted and added again with a new name, which results in the attribute value being reset to the default on all hosts of that type.
Attribute values can be literal values or can represent variables determined by your configuration.
These variables are called substitution variables. One of the most common substitution variables is :[container:installPath].
When you define a host, you can selectively override the host type's default attribute values. Default values that are not overwritten will be applied to the host. If a host-type attribute's default value is changed after hosts are created, all hosts that did not override the default value are updated to reflect the new attribute value.