Chapter 4. Creating a bootable installation medium for RHEL

Procedure

1. Connect the USB flash drive to the system.

2. Open a terminal window and display a log of recent events.

   $ dmesg|tail

   Messages resulting from the attached USB flash drive are displayed at the bottom of the log. Record the name of the connected device.

3. Log in as a root user:

   $ su -

   Enter your root password when prompted.

4. 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

5. If the inserted USB device mounts automatically, unmount it before continuing with the next steps. For unmounting, use the umount command. For more information, see Unmounting a file system with umount.

6. 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,

   • 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

     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. Run the sync command to synchronize cached writes to the device. The data transfer is complete when the # prompt appears. When you see the prompt, log out of the root account and unplug the USB drive. The USB drive is now ready to use as a boot device.

Procedure

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

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, disk0 is the OS X recovery disk, and disk1 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. Identify your USB flash drive by comparing 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. 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. Write the ISO image to the flash drive:

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

   macOS 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.

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

   # sudo dd if=/Users/user_name/Downloads/rhel-8-x86_64-boot.iso of=/dev/rdisk2

6. 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.