We can define an attribute in a role or an environment and use it to override the default settings on a node. When a role or an environment is applied during a chef-client run, the attributes defined in them are compared against those already present on the node. Finally, depending on the precedence order, the right attributes are applied to the node.
A role or environment attribute can be either a default attribute or an override attribute. It can't be a normal attribute.
A default attribute is automatically reset at every start of chef-client runs and has the lowest attribute precedence. Any cookbook should be authored to make the most of default attributes.
An override attribute, on the other hand, has higher attribute precedence over the default, force_default, and normal attributes. A cookbook should be authored to make use of override_attribute only when required.
