5.4 Installing a Precompiled KernelThe basic steps for installing a precompiled kernel are selecting and downloading the appropriate files and packages, installing those packages, and making a few minor configuration changes. 5.4.1 DownloadingYou'll find links to available packages at http://openmosix.sourceforge.net.[3] You'll need to select from among several versions and compilations. At the time this was written, there were half a dozen different kernel versions available. For each of these, there were eight possible downloads, including a README file, a kernel patch file, a source file that contains both a clean copy of the kernel and the patches, and five precompiled kernels for different processors. The precompiled versions are for an Intel 386 processor, an Intel 686 processor, an Athlon processor, Intel 686 SMP processors, or Athlon SMP processors. The Intel 386 is said to be the safest version. The Intel 686 version is for Intel Pentium II and later CPUs. With the exception of the text README file and a compressed (gz) set of patches, the files are in RPM format.[3] And while you are at it, you should also download a copy of Kris Buytaert's openMosix HOWTO from http://www.tldp.org/HOWTO/openMosix-HOWTO/. The example that follows uses the package openmosix-kernel-2.4.24-openmosix.i686.rpm for a single processor Pentium II system running Red Hat 9. Be sure you read the README file! While you are at it, you should also download a copy of the latest suitable version of the openMosix user tools from the same site. Again, you'll have a number of choices. You can download binaries in RPM or DEB format as well as the sources. For this example, the file openmosix-tools-0.3.5-1.i386.rpm was used.Perhaps the easiest thing to do is to download everything at once and burn it to a CD so you'll have everything handy as you move from machine to machine. But you could use any of the techniques described in Chapter 8, or you could use the C3 tools described in Chapter 10. Whatever your preference, you'll need to get copies of these files on each machine in your cluster.There is one last thing to do before you installcreate an emergency boot disk if you don't have one. While it is unlikely that you'll run into any problems with openMosix, you are adding a new kernel.
command as shown here: [root@fanny root]# uname -r(The last argument to mkbootdisk is the kernel version. If you can't remember this, use the command uname -r first to refresh your memory.) 5.4.2 InstallingSince we are working with RPM packages, installation is a breeze. Just change to the directory where you have the files and, as root, run rpm . [root@fanny root]# rpm -vih openmosix-kernel-2.4.24-openmosix1.i686.rpmThat's it! The kernel has been installed for you in the /boot directory.This example uses the 2.4.24-om1 release. 2.4.24-om2 should be available by the time you read this. This newer release corrects several bugs and should be used.You should also take care to use an openMosix tool set that is in sync with the kernel you are using, i.e., one that has been compiled with the same kernel header files. If you are compiling both, this shouldn't be a problem. Otherwise, you should consult the release notes for the tools. 5.4.3 Configuration ChangesWhile the installation will take care of the stuff that can be automated, there are a few changes you'll have to do manually to get openMosix running. These are very straightforward.As currently installed, the next time you reboot your systems, your loader will give you the option of starting openMosix but it won't be your default kernel. To boot to the new openMosix kernel, you'll just need to select it from the menu. However, unless you set openMosix as the default kernel, you'll need to manually select it every time you reboot a system.If you want openMosix as the default kernel, you'll need to reconfigure your boot loader. For example, if you are using grub, then you'll need to edit /etc/grub.conf to select the openMosix kernel. The installation will have added openMosix to this file, but will not have set it as the default kernel. You should see two sets of entries in this file. (You'll see more than two if you already have other additional kernels). Change the variable default to select which kernel you want as the default. The variable is indexed from 0. If openMosix is the first entry in the file, change the line to setting default so that it reads default=0.If you are using LILO, the procedure is pretty much the same except that you will need to manually create the entry in the configuration file and rerun the loader. Edit the file /etc/lilo.conf. You can use a current entry as a template. Just copy the entry, edit it to use the new kernel, and give it a new label. Change default so that it matches your new label, e.g., default=openMosix. Save the file and run the command /sbin/lilo -v.Another issue is whether your firewall will block openMosix traffic. The openMosix FAQ reports that openMosix uses UDP ports in the 5000-5700 range, UDP port 5428, and TCP ports 723 and 4660. (You can easily confirm this by monitoring network traffic, if in doubt.) You will also need to allow any other related traffic such as NFS or SSH traffic. Address this before you proceed with the configuration of openMosix.In general, security has not been a driving issue with the development of openMosix. Consequently, it is probably best to use openMosix in a restrictive environment. You should either locate your firewall between your openMosix cluster and all external networks, or you should completely eliminate the external connection.openMosix needs to know about the other machines in your cluster. You can either use the autodiscovery tool omdiscd to dynamically create a map, or you can create a static map by editing the file /etc/openmosix.map (or /etc/mosix.map or /etc/hpc.map on earlier versions of openMosix). omdiscd can be run as a foreground command or as a daemon in the background. Routing must be correctly configured for omdiscd to run correctly. For small, static clusters, it is probably easier to edit /etc/openmosix.map once and be done with it.For a simple cluster, this file can be very short. Its simplest form has one entry for each machine. In this format, each entry consists of three fieldsa unique device node number (starting at 1) for each machine, the machine's IP address, and a 1 indicating that it is a single machine. It is also possible to have a single entry for a range of machines that have contiguous IP addresses. In that case, the first two fields are the samethe node number for the first machine and the IP address of the first machine. The third field is the number of machines in the range. The address can be an IP number or a device name from your /etc/hosts file. For example, consider the following entry: 1 fanny.wofford.int 5This says that fanny.wofford.int is the first of five nodes in a cluster. Since fanny's IP address is 10.0.32.144, the cluster consists of the following five machines: 10.0.32.144, 10.0.32.145, 10.0.32.146, 10.0.32.147, and 10.0.32.148. Their node numbers are 1 through 5. You could use separate entries for each machine. For example, 1 fanny.wofford.int 1or, equivalently 1 10.0.32.144 1Again, you can use the first of these two formats only if you have entries for each machine in /etc/hosts. If you have multiple blocks of noncontiguous machines, you will need an entry for each contiguous block. If you use host names, be sure you have an entry in your host table for your node that has its actual IP address, not just the local host address. That is, you need lines that look like 127.0.0.1 localhostnot 127.0.0.1 localhost amyYou can list the map that openMosix is using with the showmap command. (This is nice to know if you are using autodiscovery.) [root@fanny etc]# showmapKeep in mind that the format depends on the map file format. If you use the range format for your map file, you will see something like this instead: [root@fanny etc]# showmapWhile the difference is insignificant, it can be confusing if you aren't expecting it.There is also a configuration file /etc/openmosix/openmosix.config. If you are using autodiscovery, you can edit this to start the discovery daemon whenever openMosix is started. This file is heavily commented, so it should be clear what you might need to change, if anything. It can be ignored for most small clusters using a map file.Of course, you will need to duplicate this configuration on each node on your cluster. You'll also need to reboot each machine so that the openMosix kernel is loaded. As root, you can turn openMosix on or off as needed. When you install the user tools package, a script called openmosix is copied to /etc/init.d so that openMosix will be started automatically. (If you are manually compiling the tools, you'll need to copy this script over.) The script takes the arguments start, stop, status, restart, and reload, as you might have guessed. For example, [root@james root]# /etc/init.d/openmosix statusUse this script to control openMosix as needed. You can also use the setpe command, briefly described later in this chapter, to control openMosix.Congratulations, you are up and running. |
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