4.4 Installation Boot Medium

A boot medium is required to invoke the installation process by loading a kernel and the initrd that contains the installation logic.

As with repositories, a large diversity of available media exists. Servers can be booted from floppy disk, CD, DVD, USB devices, over the network (PXE), or from a local hard drive.

Our experience indicates that in most environments images or physical media are utilized for installations via remote management connections like ILO boards. In some rare cases, PXE is used.

The standard image-based installation media is a normal SLES CD/DVD or an ISO image of the installation media provided by Novell via the download channels.

However, Novell Consulting favors a customized boot image with nested boot menus for the following reasons:

  • Boot options/parameters can be precoded to the boot prompt.

  • Multiple SLES versions can be installed via one single boot image, which was not possible with recent installation media of SLES.

  • The image requires only a small number of kernels, initrds, and some boot loader data. This allows you to reduce the image size to just a few MB, depending on the number of SLES versions and SLES service packs that need to be supported.

  • Customized menus can be created to reflect customer needs.

  • Background images can be included to reflect corporate identity.

This type of customized boot image with nested menus and predefined boot parameters is illustrated in the following figures:

Figure 4-1 Customized Boot Image With Nested Menus (1)

To avoid loops in the installation process, you should provide an option for a local boot in the main menu and make it the default.

Figure 4-2 Customized Boot Image With Nested Menus (2)

Multiple operating systems can be chosen from the menu displayed in the previous figure. Back allows you to return to the main menu.

Figure 4-3 Customized Boot Image With Nested Menus (3)

This figure illustrates that boot options can be predefined for each menu selection. The menu again contains a Back option to let administrators correct wrong menu selections.

A detailed description of how to create and customize such an installation medium is found in section Section 5.4.4, Creating the Customized Boot Image.