diskimage-builder/diskimage_builder/elements/bootloader/README.rst

==========
bootloader
==========

Installs ``grub[2]`` on boot partition on the system.

Arguments
=========

* ``DIB_GRUB_TIMEOUT`` sets the ``grub`` menu timeout.  It defaults to
  5 seconds.  Set this to 0 (no timeout) for fast boot times.

* ``DIB_GRUB_TIMEOUT_STYLE`` sets the visibility of the ``grub`` menu.
  It defaults to ``hidden`` (or ``countdown`` as an alias). Set this to
  ``menu`` to display the menu and then wait for the timeout set by
  ``DIB_GRUB_TIMEOUT`` to expire before booting the default entry.

* ``DIB_BOOTLOADER_DEFAULT_CMDLINE`` sets parameters that are appended
  to the ``GRUB_CMDLINE_LINUX_DEFAULT`` values in ``grub.cfg``
  configuration. It defaults to ``nofb nomodeset gfxpayload=text``.

* ``DIB_BOOTLOADER_SERIAL_CONSOLE`` sets the serial device to be
  used as a console. It defaults to ``hvc0`` for PowerPC, 
  ``ttyAMA0,115200`` for ARM64, otherwise ``ttyS0,115200``.

* ``DIB_BOOTLOADER_VIRTUAL_TERMINAL`` sets the virtual terminal be
  used as a console. It defaults to ``tty0``. When explicitly set
  to an empty string then no virtual terminal console kernel argument
  is added.
Split vm and bootloader elements In order to add more flexibility to the vm and bootloader elements, split the functionality in two different ones, and make vm depend on bootloader element. This will allow to construct more elements that depend on bootloader, and develop both elements independently. Change-Id: Iad2503b7b8fe53b768a3bc79e4cb839700fbd747 2015-12-15 19:47:19 +00:00			`==========`
			`bootloader`
			`==========`
Set grub timeout default Set the grub timeout to 5 seconds by default, and add notes on how to update this. This will stop infra having to carry an element that goes and rewrites the grub configuration. Change-Id: I556b3f48eff1b67ee8c4b9b64f749af95100fb99 2016-12-02 03:08:06 +00:00
bootloader: remove extlinux/syslinux path This is a first pass through the bootloader, that removes the extlinux and syslinux install/cleanup path. Change-Id: Ifb107796cdb6748430a124bf13ced93db9689bff 2018-02-06 05:10:40 +00:00			Installs ``grub[2]`` on boot partition on the system.
Set grub timeout default Set the grub timeout to 5 seconds by default, and add notes on how to update this. This will stop infra having to carry an element that goes and rewrites the grub configuration. Change-Id: I556b3f48eff1b67ee8c4b9b64f749af95100fb99 2016-12-02 03:08:06 +00:00
			`Arguments`
			`=========`

			* ``DIB_GRUB_TIMEOUT`` sets the ``grub`` menu timeout. It defaults to
			`5 seconds. Set this to 0 (no timeout) for fast boot times.`
Send custom parameters in bootloader to GRUB_CMDLINE Depending on the types of deployment (security, nfv...) some extra kernel flags are needed on the images. This change exposes the DIB_BOOTLOADER_DEFAULT_CMDLINE parameter, defaulting to the existing 'nofb nomodeset vga=normal', that will allow to modify these boot params. Change-Id: I67d191fa5ca44a57f776cb9739a02dd71212969c Closes-Bug: #1668890 2017-03-08 13:39:55 +00:00
Set grub timeout style Set the grub timeout style to display the menu. By default it set to 'hidden' but can be changed to 'menu' to display the menu and then wait for the timeout expire before booting the default entry. Change-Id: I8c58407ef645d528dd77efe866bfe0389cbbbd33 Signed-off-by: Maksim Malchuk <maksim.malchuk@gmail.com> 2023-09-15 15:11:15 +00:00			* ``DIB_GRUB_TIMEOUT_STYLE`` sets the visibility of the ``grub`` menu.
			It defaults to ``hidden`` (or ``countdown`` as an alias). Set this to
			``menu`` to display the menu and then wait for the timeout set by
			``DIB_GRUB_TIMEOUT`` to expire before booting the default entry.

Only append DIB_BOOTLOADER_DEFAULT_CMDLINE to default grub entry The grub.cfg has two variables [1] GRUB_CMDLINE_LINUX : used on all boots GRUB_CMDLINE_LINUX_DEFAULT : additionally used on all "normal" boots The problem with I2298675dda1f699c572b3423e7274bc8bd7c1c9d is that it appened the values in DIB_BOOTLOADER_DEFAULT_CMDLINE to both of these, resulting in duplicated arguments. I don't think we considered that GRUB_CMDLINE_LINUX_DEFAULT actually already appends to the GRUB_CMDLINE_LINUX values. Make DIB_BOOTLOADER_DEFAULT_CMDLINE only append itself to GRUB_CMDLINE_LINUX_DEFAULT. That seems to line up sensibly with the name of the variable. Documentation is enhanced around this, and a releasenote added. [1] https://help.ubuntu.com/community/Grub2/Setup Change-Id: I76b5442a9090c19a6540ed2d4ab324546f241ebf Closes: #1791736 2018-09-12 07:07:19 +00:00			* ``DIB_BOOTLOADER_DEFAULT_CMDLINE`` sets parameters that are appended
			to the ``GRUB_CMDLINE_LINUX_DEFAULT`` values in ``grub.cfg``
update grub cmdline to current kernel parameters vga=normal is depreciated, use gfxpayload=text instead Change-Id: I2e5be3b07acce14a9f3d47e24938d9da3c5b6c48 2020-06-14 05:39:42 +00:00			configuration. It defaults to ``nofb nomodeset gfxpayload=text``.
bootloader: make serial console configurable Currently, the serial console is hardcoded to ttyS0 in the bootloader element. This is a challenge for users that want to build images for some baremetal servers. Supermicro servers, for example, use ttyS1 for the serial over lan interface. This patch adds a new environment variable DIB_BOOTLOADER_SERIAL_CONSOLE that can be set to override the default. Change-Id: Ie8173be8690ac0b7164ce9e5b66d3c1c18f844d6 2019-10-03 21:14:19 +00:00
			* ``DIB_BOOTLOADER_SERIAL_CONSOLE`` sets the serial device to be
			used as a console. It defaults to ``hvc0`` for PowerPC,
			``ttyAMA0,115200`` for ARM64, otherwise ``ttyS0,115200``.
Allow custom console=tty0 argument The bootloader element now has variable DIB_BOOTLOADER_VIRTUAL_TERMINAL to customize or suppress the console=tty0 kernel argument. This is proposed to allow console=tty0 to be removed entirely as it is causing significant performance degredation in DPDK environments. Change-Id: Iba2ee5b8a6b4acdd236a770550dffd29c784ce11 Related: rhbz#2179366 2023-04-11 03:49:03 +00:00
			* ``DIB_BOOTLOADER_VIRTUAL_TERMINAL`` sets the virtual terminal be
			used as a console. It defaults to ``tty0``. When explicitly set
			`to an empty string then no virtual terminal console kernel argument`
			`is added.`