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in high-performance scheduling regimes, it cannot be directly applied to
distributed environments because of their dynamics, heterogeneity, and
lack of central control. More sophisticated resource management strate-
gies need to be proposed to address this issue.
A matchmaking paradigm can be used to address this issue in a l exible
and robust manner. The idea of matchmaking is simple. In the matchmak-
ing scheme, providers advertise resource descriptions to the matchmaker,
and customers send the request to the matchmaker. These advertisements
contain the constraints and preferences on the entities they would like to
be matched with. The matchmaker i nds compatible providers and cus-
tomers and notii es the matched entities. A claiming protocol is activated
to mutually coni rm the matched entities. Figure 7.2 illustrates the match-
making process.
Notice that the advertisements are periodically refreshed to keep the lat-
est information about participating entities. All policy considerations are
contained within the advertisements themselves: the matchmaker merely
provides the mechanism to interpret the specii ed policies in the context.
Four steps are involved in the matchmaking process in the Condor
system [1]: (1) advertising, (2) matching, (3) notii cation, and (4) claiming.
1. A semi-structured data model called classii ed advertisements
(classad) specii es the characteristics, constraints, and preferences
of the resources and requests. A classad is a mapping from attri-
bute names to expressions. Each expression may consist of simple
constant or arithmetic and logic operators. It can also contain
combinations of variables and built-in functions. Providers and
Resource matching
service
1.
Advertise
resources
2. Send a request
3. Return
qualified
resources
4. Claim resources
Provider
Customer
FIGURE 7.2
Grid matchmaking process: (1) providers advertise the resource; (2) customers
send request to matchmaker; (3) matching services i nd compatible pairs and notify the
matched entities; and (4) matched entities coni rm and complete the allocation.
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