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6.2.3. Preparing an Initial RAM Disk Update

Important

This is an advanced procedure that you should consider only if you cannot perform a driver update with any other method.
The Red Hat Enterprise Linux installation program can load updates for itself early in the installation process from a RAM disk — an area of your computer's memory that temporarily behaves as if it were a disk. You can use this same capability to load driver updates. To perform a driver update during installation, your computer must be able to boot from a preboot execution environment (PXE) server, and you must have a PXE server available on your network. Refer to Chapter 30, Setting Up an Installation Server for instructions on using PXE during installation.
To make the driver update available on your PXE server:
  1. Place the driver update image file on your installation server. Usually, you would do this by downloading it to the server from a location on the Internet specified by Red Hat or your hardware vendor. Names of driver update image files end in .iso.
  2. Copy the driver update image file into the /tmp/initrd_update directory.
  3. Rename the driver update image file to dd.img.
  4. At the command line, change into the /tmp/initrd_update directory, type the following command, and press Enter:
    find . | cpio --quiet -o -H newc | gzip -9 >/tmp/initrd_update.img
    
  5. Copy the file /tmp/initrd_update.img into the directory the holds the target that you want to use for installation. This directory is placed under the /var/lib/tftpboot/pxelinux/ directory. For example, /var/lib/tftpboot/pxelinux/rhel6/ might hold the PXE target for Red Hat Enterprise Linux 6.
  6. Edit the /var/lib/tftpboot/pxelinux/pxelinux.cfg/default file to include an entry that includes the initial RAM disk update that you just created, in the following format:
    label target-dd
    kernel target/vmlinuz
    append initrd=target/initrd.img,target/dd.img
    
    Where target is the target that you want to use for installation.
Refer to Section 6.3.4, “Select a PXE Target that Includes a Driver Update” to learn how to use an initial RAM disk update during installation.

Example 6.1. Preparing an initial RAM disk update from a driver update image file

In this example, driver_update.iso is a driver update image file that you downloaded from the Internet to a directory on your PXE server. The target that you want to PXE boot from is located in /var/lib/tftpboot/pxelinux/rhel6/
At the command line, change to the directory that holds the file and enter the following commands:
$ cp driver_update.iso /tmp/initrd_update/dd.img
$ cd /tmp/initrd_update
$ find . | cpio --quiet -c -o -H newc | gzip -9 >/tmp/initrd_update.img
$ cp /tmp/initrd_update.img /var/lib/tftpboot/pxelinux/rhel6/dd.img
Edit the /var/lib/tftpboot/pxelinux/pxelinux.cfg/default file and include the following entry:
label rhel6-dd
kernel rhel6/vmlinuz
append initrd=rhe6/initrd.img,rhel6/dd.img