Red Hat Bugzilla – Bug 59351
mkbootdisk does not create serial console boot floppy disk
Last modified: 2007-04-18 12:39:48 EDT
Description of Problem:
(1) mkbootdisk uses SYSLINUX as the boot loader. SYSLINUX has a
"serial" command but mkbootdisk has no parameter that inserts
(2) There is also no ability to add arbitrary kernel parameters.
Although this may be done from the SYSLINUX command line
it would be nicer if mkbootdisk allowed this, then an
emergency boot floppy would not fail starting a kernel.
The result of (1) is that boot disk's boot loader cannot be
controlled from a serial console.
The result of (2) is that an unattended reboot from a boot
diskette will not pass kernel parameters required for normal
operation. This includes, but is not limited to, kernel
parameters required for the serial console.
Version-Release number of selected component (if applicable):
rpm -q mkbootdisk
Steps to Reproduce:
1.Follow Remote-Serial-Console-HOWTO 2nd ed.
2.mkbootdisk --device /dev/fd0
3.Boot from floppy
4.Attempt to control SYSLINUX from serial port, say to add a kernel parameter.
SYSLINUX does not communicate with the serial port.
Because of that no parameters can be passed to the kernel,
including those instructing the kernel to use the serial
The remote serial console does not work when a boot disk
(1) The emergency boot disk should communicate with the console,
even a serial console. This may require the addition
of parameters to mkbootdisk.
(2) Emergency boot disks should boot a working kernel, even
when unattended. Some installations require kernel
parameters to have a working kernel. This may rqeuire
the addition of parameters to mkbootdisk, or for it
to examine /etc/lilo.conf or /boot/grub/menu.lst.
Reporter is author of the 2nd edition of the
Remote-Serial-Console-HOWTO, currently in final
(1) mkbootdisk should at least have an option to insert a
"serial" directive into the first line of SYSLINUX.CFG.
This should allow the serial port, bit rate and
flow control to be selected.
eg: mkbootdisk --device /dev/fd0 --serial-port 0 --serial-speed 9600
--serial-flow-control modem ...
(2) mkbootdisk should also accept kernel parameters
eg: ... --parameters 'console=ttyS0,9600n81' ...
This would be helpful for all users, not just those with
Workaround is to modify SYSLINUX.CFG on boot floppies
created with mkbootdisk, or to alter the mkbootdisk
Issue (1) is of lesser severity than issue (2). Both
should be fixed as they limit the robustness of RHL
in data center deployments.
marking as enhancement
Closing since we don't make boot floppies anymore due to 2.6 kernel