Red Hat NETWORK SATELLITE 5.3.0 Deployment Manual page 55

Bare Metal
5.8.1.2.5. Cobbler configuration
Cobbler is already set up to generate PXE configurations, but you may want to adjust the
pxe_just_once configuration option depending on how your machines BIOSes are configured, for
the best possible PXE workflow.
A common setup has PXE occur first in the BIOS order, effectively not booting off the local disk unless
the PXE server instructs the system to do so remotely. By having pxe_just_once: 1 (enabled) in /
etc/cobbler/settings, it will prevent "boot loops" where the system continually reinstalls. What
happens is that the $kickstart_done macro in the kickstart templates will expand into a directive
that indicates to the cobbler server that the system will then boot locally, instead of booting from the
network. Then, to reinstall the system, the netboot-enabled flag on the system can be toggled
back on via the Satellite GUI or Cobbler. Once enabled, the next time the system power cycles it will
PXE install instead of booting locally. At the end of each install, the server will trip the netboot-enabled
flag back to off again to tell the system to boot to the local hard drive the next time it powers up. Note
that if your kickstart is missing the $kickstart_done line in %post, this will not work, and boot loops
will occur.
With pxe_just_once set to 0, the netboot enabled flag will not be disabled after an install, so if PXE
is first in your BIOS boot order, the system will loop indefinitely. If you have the BIOS of the system set
up to boot to local hard drives first, though, there is no need to set pxe_just_once enabled, but to
re-PXE a system it is then neccessary to zero out the MBR of that system.
5.8.1.2.6. Cobbler System Record
Cobbler system records are objects within cobbler that keep track of a system and its associated
kickstart profile. To do PXE kickstarting you'll need to ensure that a Satellite kickstart profile is tied to
Cobbler system records corresponding to the machines you intend to PXE kickstart to that profile. To
make this association:
1. Visit the System details page of each system in question and click on the Provisioning link
2. Select the kickstart profile you want to associate it with
3. Click the Create Cobbler System Record button.
Once you've made this association, it will remain in place forever unless you have set
pxe_just_once to true in cobbler for any given machine. In that case the association will be broken
after a successful kickstart.
Without this association, a machine that PXE bootstraps to a Satellite server will be presented with a
menu of kickstart profiles which requires manual interaction.
5.8.1.3. Cobbler Boot ISO
The Cobbler boot ISO is a disk image that can be built on your Satellite server and burned to a CD or
DVD. You can then boot any system with it. When you do you will see a menu of available kickstarts
similar to the one you would see if you PXE boot a machine off a Cobbler server without a system
record. Simply select the kickstart you want, and the system will start to install itself. Any time you add
a kickstart within Satellite, you will need to recreate the ISO and re-burn it to an optical disc.
To create a boot ISO, log in to your Satellite server as root and run cobbler buildiso. The ISO
will contain all kernel/initrd images stored in your Satellite along with all associated kernel argument
settings. Kickstart files will be sourced remotely. This means that changes to the kickstart templates
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