5.2.3 Scalable Coherent Interface

6
Managing Ensembles
If building a Beowulf only involved assembling nodes, installing software on each one, and connecting the nodes to each other with a network, this book would end right here. But as you may have guessed, there is more to building a Beowulf than just those things. Once you have assembled a Beowulf, you have to keep it running, maintain software, add and remove user accounts, organize the file system layout, and perform countless other tasks that fall under the heading of system management. Some of these management tasks are very similar to those of traditional LAN administration, about which entire books have been written. But the rules have not yet been fully established for Beowulf system administration. It is still something of a black art, requiring not only familiarity with traditional LAN management concepts, but also some parallel programming skills and a creative ability to adapt workstation and LAN software to the Beowulf environment. This chapter attempts to describe some of the more common approaches applied by practitioners of this evolving craft as well as present some alternative procedures that have not yet become common practice.
Even though both corporate LANs and Beowulf systems are composed of collections of networked PCs, they differ significantly in terms of their installation, use, maintenance, and overall management. A LAN is usually formed from a loosely coupled heterogeneous collection of computers that share disk and printing resources, in addition to some network services, such as web and database servers. A Beowulf cluster is a more tightly coupled collection of computers where the majority of components are identically configured and collectively operate as a single machine.
6.1 System Access Models
Before assigning IP addresses to Beowulf nodes, designing the network topology, and booting the machine, you need to decide how the system will be accessed. System access literally refers to how a user can log in to a system and use the machine. Allowable system access modes relate directly to how you configure your system both logically and physically. There are three principal schemes for permitting user access to Beowulf machines, the first of which is seldom used.
6.1.1 The Stand-alone System
The most basic way of configuring a Beowulf is to set it up as a stand-alone system unattached to any external networks. This design requires a user to be in the same room as the Beowulf, sitting at its front-end keyboard and monitor to write and

 



How to Build a Beowulf
How to Build a Beowulf: A Guide to the Implementation and Application of PC Clusters (Scientific and Engineering Computation)
ISBN: 026269218X
EAN: 2147483647
Year: 1999
Pages: 134

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