This Procedure is to upgrade RHEL 4 to RHEL 5
Note: Red Hat warning about upgrading from an earlier major versions.

STEPS
1. Obtain an ISO image of the OS from the Redhat site.
2. Log in to ILO and mount the ISO image.
HP ILO:

• Once in the ILO, navigate to the "Virtual Devices" tab and click on "Virtual Media"

• After clicking on "Virtual Media" a window will pop up allowing you to mount a virtual cd. Select on "Local Image File" and click browse.

• Browse to your ISO image

• Click "Connect"

Dell ILO

• Navigate to the "Console/Media" tab and click on "Launch Viewer"

• On the Console, Go to "Virtual Media" and click on Launch "Virtual Media"

• The Virtual Media Session will start and click on "Add Image"

• Browse to your ISO image

• Once the Image is added, selected "Mapped".

4. Reboot the server.
5. As the server boots up, make sure the bios is set to boot from CD/DVD
6. Once the server boots up from the ISO image you will see the following screen.

7. Type the boot command below and press enter:
linux upgradeany
8. Follow the upgrade prompt.
9. Once the upgrade is complete the server will reboot.
10. Once the server is back up login and register the server with Red Hat with the command below:
rhn_register
Note: Here is the link to the Red Hat documentation: http://docs.redhat.com/docs/en-US/Red_Hat_Enterprise_Linux/5/html/Installation_Guide/ch-upgrade-x86.html