5.3.2 Zero-copy Protocols

MAC address of a misbehaving node, you can find it by visually scanning the labels. All in all, it is easier if the mapping between MAC addresses, hostnames and IP addresses changes as infrequently as possible.
6.3 Cloning Nodes
After choosing a configuration scheme, the next step in turning your mass of machines into a Beowulf is to install an operating system and standard software on all of the nodes. This can be a daunting task for even a small system containing only 8 nodes. After reading Chapter 4, you should be familiar with how to install Linux on a single machine. In practice, you do not want to go through that entire procedure dozens of times. Fortunately, you can install one internal node, and clone the remaining nodes.
The internal nodes of a Beowulf cluster are almost always identically configured. The hardware can be slightly different, incorporating different generation processors, disks, and network interface cards. But the file system layout, kernel version, and installed software are the same. Only the worldly node exhibits differences, as it generally serves as the repository of user home directories and centralized software installations exported via NFS.
In general, you will install the operating system and extra support software on the worldly node first. Then you will configure a single internal node, and clone the rest from it. This way you only have to configure two systems. Aside from saving time up front, cloning also facilitates major system upgrades. You may decide to completely change the software configuration of your internal nodes, requiring an update to all of the nodes. By cloning internal nodes, you only have to go through the reconfiguration process for one machine. In addition, cloning makes it easier to recover from certain unexpected events like disk failures or accidental file system corruption. All you have to do is install a new disk (in the case of a disk failure) and reclone the node.
At the moment, there are no standard software distributions for node cloning. Most Beowulf sites either write their own software, or borrow it from colleagues, but most of the software follows the basic procedure we are about to describe. Node cloning relies on the BOOTP protocol discussed in the previous section to provide a node with an IP address and a root file system for the duration of the cloning procedure. In brief, the following steps are involved:
1. Manually configure a single internal node.
2. Create tar files for each partition.

 



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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