Preparing for your installation

Connect the USB flash drive to the system.

Open a terminal window and run the dmesg command:

$ dmesg|tail

Switch to user root:

$ su -

Enter your root password when prompted.

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

Run the dd command to write the ISO image directly to the USB device.

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

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

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.

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

Connect the USB flash drive to the system.

Open Fedora Media Writer.

From the main window, click Custom Image and select the previously downloaded CentOS ISO image.

From Write Custom Image window, select the drive that you want to use.

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.

When the operation completes, unmount the USB drive. The USB drive is now ready to be used as a boot device.

Connect the USB flash drive to the system.

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                        *8.0 GB     disk2
1:               Windows_NTFS SanDisk USB             8.0 GB     disk2s1

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.

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

Log in as root:

$ su -

Enter your root password when prompted.

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 bs=1m>

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

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

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.

Install the nfs-utils package:

# yum install nfs-utils

Copy the DVD1 ISO image to a directory on the NFS server.

Open the /etc/exports file using a text editor and add a line with the following syntax:

/exported_directory/ clients

Replace /exported_directory/ with the full path to the directory with the ISO image. Replace clients with the host name or IP address of the target system, the subnetwork that all target systems can use to access the ISO image, or the asterisk sign (*) if you want to allow any system with network access to the NFS server to use the ISO image. See the exports(5) man page for detailed information about the format of this field.

/centos8-install *

Save the /etc/exports file and exit the text editor.

Start the nfs service:

# systemctl start nfs-server.service

# systemctl reload nfs-server.service

Install the httpd package:

# yum install httpd

Copy the DVD1 ISO image to the HTTP(S) server.

Mount the DVD1 ISO image, using the mount command, to a suitable directory:

# mkdir /mnt/centos8-install/
# mount -o loop,ro -t iso9660 /image_directory/image.iso /mnt/centos8-install/

Copy the files from the mounted image to the HTTP(S) server root. This command creates the /var/www/html/centos8-install/ directory with the contents of the image.

# cp -r /mnt/centos8-install/ /var/www/html/

Start the httpd service:

# systemctl start httpd.service

Install the vsftpd package by running the following command as root:

# yum install vsftpd

Open and edit the /etc/vsftpd/vsftpd.conf configuration file in a text editor.

Configure the server firewall.

Copy the DVD1 ISO image to the FTP server.

Mount the DVD1 ISO image, using the mount command, to a suitable directory:

# mkdir /mnt/centos8-install
# mount -o loop,ro -t iso9660 /image-directory/image.iso /mnt/centos8-install

Copy the files from the mounted image to the FTP server root:

# mkdir /var/ftp/centos8-install
# cp -r /mnt/centos8-install/ /var/ftp/

Make sure that the correct SELinux context and access mode is set on the copied content:

# restorecon -r /var/ftp/centos8-install
# find /var/ftp/centos8-install -type f -exec chmod 444 {} \;
# find /var/ftp/centos8-install -type d -exec chmod 755 {} \;

Start the vsftpd service:

# systemctl start vsftpd.service

# systemctl restart vsftpd.service