107 lines
3.8 KiB
ReStructuredText
107 lines
3.8 KiB
ReStructuredText
.. _kernel-boot-parameters:
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Appending kernel parameters to boot instances
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---------------------------------------------
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The Bare Metal service supports passing custom kernel parameters to boot instances to fit
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users' requirements. The way to append the kernel parameters is depending on how to boot instances.
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Network boot
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~~~~~~~~~~~~
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Currently, the Bare Metal service supports assigning unified kernel parameters to PXE
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booted instances by:
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* Modifying the ``[pxe]/pxe_append_params`` configuration option, for example::
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[pxe]
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pxe_append_params = quiet splash
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* Copying a template from shipped templates to another place, for example::
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https://git.openstack.org/cgit/openstack/ironic/tree/ironic/drivers/modules/pxe_config.template
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Making the modifications and pointing to the custom template via the configuration
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options: ``[pxe]/pxe_config_template`` and ``[pxe]/uefi_pxe_config_template``.
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Local boot
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~~~~~~~~~~
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For local boot instances, users can make use of configuration drive
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(see :ref:`configdrive`) to pass a custom
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script to append kernel parameters when creating an instance. This is more
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flexible and can vary per instance.
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Here is an example for grub2 with ubuntu, users can customize it
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to fit their use case:
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.. code:: python
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#!/usr/bin/env python
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import os
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# Default grub2 config file in Ubuntu
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grub_file = '/etc/default/grub'
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# Add parameters here to pass to instance.
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kernel_parameters = ['quiet', 'splash']
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grub_cmd = 'GRUB_CMDLINE_LINUX'
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old_grub_file = grub_file+'~'
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os.rename(grub_file, old_grub_file)
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cmdline_existed = False
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with open(grub_file, 'w') as writer, \
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open(old_grub_file, 'r') as reader:
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for line in reader:
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key = line.split('=')[0]
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if key == grub_cmd:
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#If there is already some value:
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if line.strip()[-1] == '"':
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line = line.strip()[:-1] + ' ' + ' '.join(kernel_parameters) + '"'
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cmdline_existed = True
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writer.write(line)
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if not cmdline_existed:
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line = grub_cmd + '=' + '"' + ' '.join(kernel_parameters) + '"'
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writer.write(line)
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os.remove(old_grub_file)
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os.system('update-grub')
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os.system('reboot')
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Console
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~~~~~~~
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In order to change default console configuration in the Bare Metal
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service configuration file (``[pxe]`` section in ``/etc/ironic/ironic.conf``),
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include the serial port terminal and serial speed. Serial speed must be
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the same as the serial configuration in the BIOS settings, so that the
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operating system boot process can be seen in the serial console or web console.
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Following examples represent possible parameters for serial and web console
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respectively.
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* Node serial console. The console parameter ``console=ttyS0,115200n8``
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uses ``ttyS0`` for console output at ``115200bps, 8bit, non-parity``, e.g.::
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[pxe]
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# Additional append parameters for baremetal PXE boot.
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pxe_append_params = nofb nomodeset vga=normal console=ttyS0,115200n8
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* For node web console configuration is similar with the addition of ``ttyX``
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parameter, see example::
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[pxe]
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# Additional append parameters for baremetal PXE boot.
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pxe_append_params = nofb nomodeset vga=normal console=tty0 console=ttyS0,115200n8
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For detailed information on how to add consoles see the reference documents
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`kernel params`_ and `serial console`_.
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In case of local boot the Bare Metal service is not able to control kernel boot
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parameters. To configure console locally, follow 'Local boot' section above.
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.. _`kernel params`: https://www.kernel.org/doc/Documentation/kernel-parameters.txt
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.. _`serial console`: https://www.kernel.org/doc/Documentation/serial-console.txt
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