Red hat linux boot disk

Создание загрузочного диска

Если вы зарегистрированы под именем root, вам может потребоваться всего несколько минут чтобы создать новый загрузочный диск или скопировать уже существующий.

Загрузочный диск нужен вам по нескольким причинам. Он поможет вам восстановить систему после сбоя, протестировать новое полученное и скомпилированное ядро, а также использовать на одном компьютере несколько операционных систем.

Во время установки Red Hat Linux вам предоставляется возможность сделать загрузочный диск. Если вы решили не создавать диск во время установки, теперь у вас есть возможность сделать это самостоятельно.

Чтобы создать загрузочный диск:

Перейдите в командную оболочку и убедитесь в том, что вы работаете под именем root. В приглашении командной строки, которое выглядит например так: [newuser@localhost newuser]$ , введите:

[newuser@localhost newuser]$ su — Password: вашпарольroot [root@localhost newuser]#

Вставьте в дисковод обычную дискету.

Обращение к гибкому диску

В Linux, дисковод гибких дисков обычно называется /dev/fd0 .

Если вы использовали это дискету раньше, убедитесь в том что информация на ней вам не нужна!

На экране отображается версия ядра. Ядро — это сердце любой системы Linux. Версия ядра будет иметь примерно следующий вид:

После 2.4 могут быть разные числа, например 2.4.1 ).

Теперь, когда вы определили версию ядра, вы можете указать программе mkbootdisk , какое ядро записать на вашу дискету.

Введите следующую команду:

mkbootdisk —device /dev/fd0 2.4. x — yy

Если вы укажите программе mkbootdisk куда скопировать ядро, по умолчанию оно будет записано на дискету (в /dev/fd0 ).

Нажмите [Enter] . Когда лампочка в вашем дисководе потухнет, извлеките и пометьте дискету.

Если ваш экран загроможден ненужной информацией, вы можете в любой момент очистить его, введя в приглашении команду clear .

Команда su выполняет подмену пользователя и позволяет вам временно зарегистрироваться под именем другого пользователя. Если вы введете команду su и нажмёте [Enter] , вы станете пользователем root (также называемым супер-пользователем) оставаясь в своей оболочке. Выполнив su — , вы станете root в его оболочке, также как если бы вы вошли в систему под именем root. В чём же разница? Есть определённый набор команд, которые могут быть выполнены только пользователем root; с помощью su — вы можете, не производя выход и вход в систему, выполнить такие команды.

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Chapter 7. Booting the installation

After you have created bootable media you are ready to boot the Red Hat Enterprise Linux installation.

7.1. Boot menu

The Red Hat Enterprise Linux boot menu is displayed using GRand Unified Bootloader version 2 (GRUB2) when your system has completed loading the boot media.

Figure 7.1. Red Hat Enterprise Linux boot menu

The boot menu provides several options in addition to launching the installation program. If you do not make a selection within 60 seconds, the default boot option (highlighted in white) is run. To select a different option, use the arrow keys on your keyboard to make your selection and press the Enter key.

You can customize boot options for a particular menu entry:

• On BIOS-based systems: Press the Tab key and add custom boot options to the command line. You can also access the boot: prompt by pressing the Esc key but no required boot options are preset. In this scenario, you must always specify the Linux option before using any other boot options.
• On UEFI-based systems: Press the e key and add custom boot options to the command line. When ready press Ctrl + X to boot the modified option.

Table 7.1. Boot menu options

Install Red Hat Enterprise Linux 8

Use this option to install Red Hat Enterprise Linux using the graphical installation program. For more information, see Performing a quick install with GUI

Test this media & install Red Hat Enterprise Linux 8

Use this option to check the integrity of the installation media. For more information, see Verifying a boot media

Troubleshooting >

Use this option to resolve various installation issues. Press Enter to display its contents.

Table 7.2. Troubleshooting options

Troubleshooting > Install Red Hat Enterprise Linux 8 in basic graphics mode

Use this option to install Red Hat Enterprise Linux in graphical mode even if the installation program is unable to load the correct driver for your video card. If your screen is distorted when using the Install Red Hat Enterprise Linux 8 option, restart your system and use this option. For more information, see Cannot boot into graphical installation

Troubleshooting > Rescue a Red Hat Enterprise Linux system

Use this option to repair any issues that prevent you from booting. For more information, see Using a rescue mode

Troubleshooting > Run a memory test

Use this option to run a memory test on your system. Press Enter to display its contents. For more information, see memtest86

Troubleshooting > Boot from local drive

Use this option to boot the system from the first installed disk. If you booted this disk accidentally, use this option to boot from the hard disk immediately without starting the installation program.

7.2. Types of boot options

The two types of boot options are those with an equals «=» sign, and those without an equals » literal»>inst .

Options with an equals » literal»>= symbol. For example, the inst.vncpassword= option must contain a value, in this example, a password. The correct syntax for this example is inst.vncpassword=password . Options without an equals » literal»>rd.live.check option forces the installation program to verify the installation media before starting the installation. If this boot option is present, the installation program performs the verification and if the boot option is not present, the verification is skipped.

7.3. Editing the boot: prompt in BIOS

When using the boot: prompt, the first option must always specify the installation program image file that you want to load. In most cases, you can specify the image using the keyword. You can specify additional options according to your requirements.

Prerequisites

• You have created bootable installation media (USB, CD or DVD).
• You have booted the installation from the media, and the installation boot menu is open.

1. With the boot menu open, press the Esc key on your keyboard.
2. The boot: prompt is now accessible.
3. Press the Tab key on your keyboard to display the help commands.
4. Press the Enter key on your keyboard to start the installation with your options. To return from the boot: prompt to the boot menu, restart the system and boot from the installation media again.

The boot: prompt also accepts dracut kernel options. A list of options is available in the dracut.cmdline(7) man page.

7.4. Editing predefined boot options using the > prompt

In BIOS-based AMD64 and Intel 64 systems, you can use the > prompt to edit predefined boot options. To display a full set of options, select Test this media and install RHEL 8 from the boot menu.

Prerequisites

• You have created bootable installation media (USB, CD or DVD).
• You have booted the installation from the media, and the installation boot menu is open.

1. From the boot menu, select an option and press the Tab key on your keyboard. The > prompt is accessible and displays the available options.
2. Append the options that you require to the > prompt.
3. Press Enter to start the installation.
4. Press Esc to cancel editing and return to the boot menu.

7.5. Editing the GRUB2 menu for the UEFI-based systems

The GRUB2 menu is available on UEFI-based AMD64, Intel 64, and 64-bit ARM systems.

Prerequisites

• You have created bootable installation media (USB, CD or DVD).
• You have booted the installation from the media, and the installation boot menu is open.

1. From the boot menu window, select the required option and press e .
2. On UEFI systems, the kernel command line starts with linuxefi . Move the cursor to the end of the linuxefi kernel command line.
3. Edit the parameters as required. For example, to configure one or more network interfaces, add the ip= parameter at the end of the linuxefi kernel command line, followed by the required value.
4. When you finish editing, press Ctrl + X to start the installation using the specified options.

7.6. Booting the installation from a USB, CD, or DVD

Follow the steps in this procedure to boot the Red Hat Enterprise Linux installation using a USB, CD, or DVD. The following steps are generic. Consult your hardware manufacturer’s documentation for specific instructions.

Prerequisite

You have created bootable installation media (USB, CD or DVD). See Creating a bootable DVD or CD for more information.

1. Power off the system to which you are installing Red Hat Enterprise Linux.
2. Disconnect any drives from the system.
3. Power on the system.
4. Insert the bootable installation media (USB, DVD, or CD).
5. Power off the system but do not remove the boot media.
6. Power on the system.

You might need to press a specific key or combination of keys to boot from the media or configure the Basic Input/Output System (BIOS) of your system to boot from the media. For more information, see the documentation that came with your system.

The installation program automatically begins if no action is performed in the boot window within 60 seconds.

1. UEFI-based systems: Press E to enter edit mode. Change the predefined command line to add or remove boot options. Press Enter to confirm your choice.
2. BIOS-based systems: Press the Tab key on your keyboard to enter edit mode. Change the predefined command line to add or remove boot options. Press Enter to confirm your choice.

Additional Resources

7.7. Booting the installation from a network using PXE

When installing Red Hat Enterprise Linux on a large number of systems simultaneously, the best approach is to boot from a PXE server and install from a source in a shared network location. Follow the steps in this procedure to boot the Red Hat Enterprise Linux installation from a network using PXE.

To boot the installation process from a network using PXE, you must use a physical network connection, for example, Ethernet. You cannot boot the installation process with a wireless connection.

Prerequisites

• You have configured a TFTP server, and there is a network interface in your system that supports PXE. See Additional resources for more information.
• You have configured your system to boot from the network interface. This option is in the BIOS, and can be labeled Network Boot or Boot Services .
• You have verified that the BIOS is configured to boot from the specified network interface and supports the PXE standard. For more information, see your hardware’s documentation.

1. Verify that the network cable is attached. The link indicator light on the network socket should be lit, even if the computer is not switched on.
2. Switch on the system. Depending on your hardware, some network setup and diagnostic information can be displayed before your system connects to a PXE server. When connected, a menu is displayed according to the PXE server configuration.
3. Press the number key that corresponds to the option that you require.

In some instances, boot options are not displayed. If this occurs, press the Enter key on your keyboard or wait until the boot window opens.

The installation program automatically begins if no action is performed in the boot window within 60 seconds.

1. UEFI-based systems: Press E to enter edit mode. Change the predefined command line to add or remove boot options. Press Enter to confirm your choice.
2. BIOS-based systems: Press the Tab key on your keyboard to enter edit mode. Change the predefined command line to add or remove boot options. Press Enter to confirm your choice.

Additional Resources

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