Chapter 4. Creating a bootable installation medium for RHEL

This section contains information about using the ISO image file that you have downloaded to create a bootable physical installation medium, such as a USB, DVD, or CD. For more information about downloading the ISO images, see Downloading the installation ISO image

4.1. Installation boot media options

There are several options available to boot the Red Hat Enterprise Linux installation program.

Full installation DVD or USB flash drive
Create a full installation DVD or USB flash drive using the DVD ISO image. The DVD or USB flash drive can be used as a boot device and as an installation source for installing software packages. Due to the size of the DVD ISO image, a DVD or USB flash drive are the recommended media types.
Minimal installation DVD, CD, or USB flash drive
Create a minimal installation CD, DVD, or USB flash drive using the Boot ISO image, which contains only the minimum files necessary to boot the system and start the installation program.
Important

If you are not using the Content Delivery Network (CDN) to download the required software packages, the Boot ISO image requires an installation source that contains the required software packages.

4.2. Creating a bootable DVD or CD

You can create a bootable installation DVD or CD using burning software and a CD/DVD burner. The exact steps to produce a DVD or CD from an ISO image file vary greatly, depending on the operating system and disc burning software installed. Consult your system’s burning software documentation for the exact steps to burn a CD or DVD from an ISO image file.

Warning

You can create a bootable DVD or CD using either the DVD ISO image (full install) or the Boot ISO image (minimal install). However, the DVD ISO image is larger than 4.7 GB, and as a result, it might not fit on a single or dual-layer DVD. Check the size of the DVD ISO image file before you proceed. A USB key is recommended when using the DVD ISO image to create bootable installation media.

4.3. Creating a bootable USB device on Linux

Follow this procedure to create a bootable USB device on a Linux system.

Note

This procedure is destructive and data on the USB flash drive is destroyed without a warning.

Prerequisites

  • You have downloaded an installation ISO image as described in Downloading the installation ISO image.
  • The DVD ISO image is larger than 4.7 GB, so a USB flash drive that is large enough to hold the ISO image is required.

Procedure

  1. Connect the USB flash drive to the system.
  2. Open a terminal window and run the dmesg command:

    $ dmesg|tail

    The dmesg command returns a log that details all recent events. Messages resulting from the attached USB flash drive are displayed at the bottom of the log. Record the name of the connected device.

  3. Switch to user root:

    $ su -
  4. Enter your root password when prompted.
  5. Find the device node assigned to the drive. In this example, the drive name is sdd.

    # dmesg|tail
    [288954.686557] usb 2-1.8: New USB device strings: Mfr=0, Product=1, SerialNumber=2
    [288954.686559] usb 2-1.8: Product: USB Storage
    [288954.686562] usb 2-1.8: SerialNumber: 000000009225
    [288954.712590] usb-storage 2-1.8:1.0: USB Mass Storage device detected
    [288954.712687] scsi host6: usb-storage 2-1.8:1.0
    [288954.712809] usbcore: registered new interface driver usb-storage
    [288954.716682] usbcore: registered new interface driver uas
    [288955.717140] scsi 6:0:0:0: Direct-Access     Generic  STORAGE DEVICE   9228 PQ: 0 ANSI: 0
    [288955.717745] sd 6:0:0:0: Attached scsi generic sg4 type 0
    [288961.876382] sd 6:0:0:0: sdd Attached SCSI removable disk
  6. Run the dd command to write the ISO image directly to the USB device.

    # dd if=/image_directory/image.iso of=/dev/device

    Replace /image_directory/image.iso with the full path to the ISO image file that you downloaded, and replace device with the device name that you retrieved with the dmesg command. In this example, the full path to the ISO image is /home/testuser/Downloads/rhel-8-x86_64-boot.iso, and the device name is sdd:

    # dd if=/home/testuser/Downloads/rhel-8-x86_64-boot.iso of=/dev/sdd
    Note

    Ensure that you use the correct device name, and not the name of a partition on the device. Partition names are usually device names with a numerical suffix. For example, sdd is a device name, and sdd1 is the name of a partition on the device sdd.

  7. Wait for the dd command to finish writing the image to the device. The data transfer is complete when the # prompt appears. When the prompt is displayed, log out of the root account and unplug the USB drive. The USB drive is now ready to be used as a boot device.

4.4. Creating a bootable USB device on Windows

Follow the steps in this procedure to create a bootable USB device on a Windows system. The procedure varies depending on the tool. Red Hat recommends using Fedora Media Writer, available for download at https://github.com/FedoraQt/MediaWriter/releases.

Note
  • Fedora Media Writer is a community product and is not supported by Red Hat. You can report any issues with the tool at https://github.com/FedoraQt/MediaWriter/issues.
  • This procedure is destructive and data on the USB flash drive is destroyed without a warning.

Prerequisites

  • You have downloaded an installation ISO image as described in Downloading the installation ISO image.
  • The DVD ISO image is larger than 4.7 GB, so a USB flash drive that is large enough to hold the ISO image is required.

Procedure

  1. Download and install Fedora Media Writer from https://github.com/FedoraQt/MediaWriter/releases.

    Note

    To install Fedora Media Writer on Red Hat Enterprise Linux, use the pre-built Flatpak package. You can obtain the package from the official Flatpak repository Flathub.org at https://flathub.org/apps/details/org.fedoraproject.MediaWriter.

  2. Connect the USB flash drive to the system.
  3. Open Fedora Media Writer.
  4. From the main window, click Custom Image and select the previously downloaded Red Hat Enterprise Linux ISO image.
  5. From Write Custom Image window, select the drive that you want to use.
  6. Click Write to disk. The boot media creation process starts. Do not unplug the drive until the operation completes. The operation may take several minutes, depending on the size of the ISO image, and the write speed of the USB drive.
  7. When the operation completes, unmount the USB drive. The USB drive is now ready to be used as a boot device.

4.5. Creating a bootable USB device on Mac OS X

Follow the steps in this procedure to create a bootable USB device on a Mac OS X system.

Note

This procedure is destructive and data on the USB flash drive is destroyed without a warning.

Prerequisites

  • You have downloaded an installation ISO image as described in Downloading the installation ISO image.
  • The DVD ISO image is larger than 4.7 GB, so a USB flash drive that is large enough to hold the ISO image is required.

Procedure

  1. Connect the USB flash drive to the system.
  2. Identify the device path with the diskutil list command. The device path has the format of /dev/disknumber, where number is the number of the disk. The disks are numbered starting at zero (0). Typically, Disk 0 is the OS X recovery disk, and Disk 1 is the main OS X installation. In the following example, the USB device is disk2:

    $ diskutil list
    /dev/disk0
    #:                       TYPE NAME                    SIZE       IDENTIFIER
    0:      GUID_partition_scheme                        *500.3 GB   disk0
    1:                        EFI EFI                     209.7 MB   disk0s1
    2:          Apple_CoreStorage                         400.0 GB   disk0s2
    3:                 Apple_Boot Recovery HD             650.0 MB   disk0s3
    4:          Apple_CoreStorage                         98.8 GB    disk0s4
    5:                 Apple_Boot Recovery HD             650.0 MB   disk0s5
    /dev/disk1
    #:                       TYPE NAME                    SIZE       IDENTIFIER
    0:                  Apple_HFS YosemiteHD             *399.6 GB   disk1
    Logical Volume on disk0s1
    8A142795-8036-48DF-9FC5-84506DFBB7B2
    Unlocked Encrypted
    /dev/disk2
    #:                       TYPE NAME                    SIZE       IDENTIFIER
    0:     FDisk_partition_scheme                        *8.1 GB     disk2
    1:               Windows_NTFS SanDisk USB             8.1 GB     disk2s1
  3. To identify your USB flash drive, compare the NAME, TYPE and SIZE columns to your flash drive. For example, the NAME should be the title of the flash drive icon in the Finder tool. You can also compare these values to those in the information panel of the flash drive.
  4. Use the diskutil unmountDisk command to unmount the flash drive’s filesystem volumes:

    $ diskutil unmountDisk /dev/disknumber
    					Unmount of all volumes on disknumber was successful

    When the command completes, the icon for the flash drive disappears from your desktop. If the icon does not disappear, you may have selected the wrong disk. Attempting to unmount the system disk accidentally returns a failed to unmount error.

  5. Log in as root:

    $ su -
  6. Enter your root password when prompted.
  7. Use the dd command as a parameter of the sudo command to write the ISO image to the flash drive:

    # sudo dd if=/path/to/image.iso of=/dev/rdisknumber
    Note

    Mac OS X provides both a block (/dev/disk*) and character device (/dev/rdisk*) file for each storage device. Writing an image to the /dev/rdisknumber character device is faster than writing to the /dev/disknumber block device.

  8. To write the /Users/user_name/Downloads/rhel-8-x86_64-boot.iso file to the /dev/rdisk2 device, run the following command:

    # sudo dd if=/Users/user_name/Downloads/rhel-8-x86_64-boot.iso of=/dev/rdisk2
  9. Wait for the dd command to finish writing the image to the device. The data transfer is complete when the # prompt appears. When the prompt is displayed, log out of the root account and unplug the USB drive. The USB drive is now ready to be used as a boot device.