When you create an install service for the first time, a default manifest (default.xml) is automatically created and associated with that service. All clients of the same architecture for which the service was created will use the default manifest during installation.
With multiple and customized manifests, you would need to define criteria to associate manifests with the correct clients. Clients can use only one manifest in one installation instance. Thus, the criteria ensure that the correct clients use a specific manifest and that non-matching systems are excluded.
Keywords that define criteria form a hierarchy. If a client matches criteria defined for multiple manifests, the manifest with the higher priority keyword will be used. The installadm tool verifies that criteria of the same type do not overlap.
Suppose that for a SPARC service, two manifests are assigned. For ManifestA, SPARC M8 servers constitute a platform criterion. ManifestB specifies an address for a MAC criterion, which has a higher priority. A SPARC M8 client whose MAC address matches the MAC criterion will use ManifestB, even though the client also matches the platform criterion of ManifestA.
For the list of keywords and their priorities, see Figure 2, Table 2, Criteria Keywords and Criteria Hierarchy.