5.5.1 Remote Procedure Calls

		.default:\          :sm=255.255.255.0:\          :ht=ether:\          :gw=192.168.1.1:\          :rp=/export/nfsroot/:  b002:ip=192.168.1.2:ha=0080c8638a2c:tc=.default  b003:ip=192.168.1.3:ha=0080c86359d9:tc=.default  b004:ip=192.168.1.4:ha=0080c86795c8:tc=.default

 

		Program 6.1: Sample bootptab for a system with three nodes, b002, b003 and b004.

		After making it to this final point, everything should be in place on the server to start the clone process. All that remains is to create a boot floppy that will launch the cloning process on the client.

		6.3.4 Building a Boot Clone Floppy

		Building a boot disk is yet another instance of Beowulf administration that requires familiarity with compiling the Linux kernel. This is because the boot disk does not actually perform the node cloning, but bootstraps the cloning procedure by talking to a bootp server to get an IP address and mount a root file system  over the network. The default kernel you may have installed more than likely does not have this capability built-in. It is necessary to build a kernel with these abilities, commonly called an NFSROOT kernel because it mounts a root file system over NFS. The CACR Beowulf cloning software2 contains a pre-built NFSROOT kernel. but it cannot be guaranteed to work with your system. The problem is that not all network drivers can be compiled into the kernel, and some even conflict with each other. Therefore, it is possible that the network drivers required by your system are not contained in our pre-built kernel.

		If you are not already familiar with how to compile the Linux kernel, you can learn more about it from one of the suggested references listed in Section 4.10 or you can jump right into it after reading the instructions in the README file distributed with the kernel source, usually in /usr/src/linux. When you compile the kernel for a clone floppy, you must make sure that NFS root file system support is enabled.

		In addition, include the network drivers for the interface cards you are using. Once compiled, the kernel will be stored in a file called zImage or bzImage depending on what compression option you use. If you use this unaltered kernel to create a

		2The   CACR   Beowulf  node   cloning   software  can   be   downloaded  from http://www.cacr.caltech.edu/beowulf/.