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4.2. Deploying RHEV Hypervisors with PXE and tftp

This section covers installing RHEV Hypervisors over a network with PXE and tftp. Configuring the DHCP and tftp servers for PXE booting is outside the scope of this book.
  1. Install the rhev-hypervisor package and extract the livecd-iso-to-pxeboot script. Refer to Procedure 4.1, “Downloading and Installing the Package”.
  2. Create vmlinuz and initrd images with livecd-iso-to-pxeboot: 
    # /usr/share/rhev-hypervisor/livecd-iso-to-pxeboot /usr/share/rhev-hypervisor/rhev-hypervisor.iso
    Your pxeboot image is complete.

Copy tftpboot/ subdirectory to /tftpboot or a subdirectory of /tftpboot.
Set up your DHCP, TFTP and PXE server to serve /tftpboot/.../pxeboot.0

Note: The initrd image contains the whole CD ISO and is consequently
very large.  You will notice when pxebooting that initrd can take a
long time to download.  This is normal behaviour.
  3. The output of livecd-iso-to-pxeboot command is a directory called tftpboot that has the following files in it:
    • pxelinux.0
    • pxelinux.cfg/default
    • vmlinuz0
    • initrd0.img
  4. The vmlinuz and initrd files can be imported into a cobbler server or any other PXE and tftp servers.
    Import the files to the appropriate directory.
  5. The pxelinux.cfg/default file provides a template for configuring the PXE server to export the Hypervisor image: 
    DEFAULT pxeboot
TIMEOUT 20
PROMPT 0
LABEL pxeboot
        KERNEL vmlinuz0
        APPEND rootflags=loop initrd=initrd0.img root=/rhev-hypervisor.iso rootfstype=auto ro liveimg
               check crashkernel=128M@16M elevator=deadline processor.max_cstate=1
ONERROR LOCALBOOT 0
    PXE booted Hypervisors rely on the PXE server passing the MAC address of the PXE interface to the kernel. This is provided by using the IPAPPEND 2 parameter.
    Modify the templates as required for your environment.

Warning

The root=/rhev-hypervisor.iso parameter in pxelinux.cfg/default is a default value. If the ISO file you are using has a name other than rhev-hypervisor.iso it should be passed when calling livecd-iso-to-pxeboot. For example, for the ISO file rhev_hypervisor_2_2.iso use the command livecd-iso-to-pxeboot rhev_hypervisor_2_2.iso. This will produce the correct parameter root=/rhev_hypervisor_2_2.iso in pxelinux.cfg/default.

4.2.1. Booting a RHEV Hypervisor with PXE

For network booting the network interface card must support PXE booting.
To boot a RHEV Hypervisor from a PXE server:
  1. Enter your system's BIOS. On most systems, the key or combination of keys is prompted shortly after the system has power. Usually, this key is delete, F1 or F2.
  2. Enable network booting if network booting is disabled.
  3. Set the network interface card as the first boot device.
  4. Boot the system. If the PXE parameters are configured correctly an automated installation should begin.
  5. Change or disable network booting after the RHEV Hypervisor is installed. This is to avoid overwriting the installation on each reboot (unless this is desired functionality) and to prevent certain security vulnerabilities.

Warning

The network interface used for PXE boot installation must be same interface used to connect to the RHEV Manager.

Note

For more information on the kernel parameters, refer to Section 5.2, “RHEV Hypervisor Kernel Parameters and Automated Installation”.
The RHEV Hypervisor should now be installed.