Chapter 11. Advanced configuration options

Procedure

1. Export the installation ISO image or the installation tree to an NFS, HTTPS, HTTP, or FTP server.
2. Configure the HTTP or TFTP server and DHCP server, and start the HTTP or TFTP service on the server.
3. Boot the client and start the installation.

Procedure

1. Install the DHCP server:

   yum install dhcp-server

2. Set up a DHCPv4 server. Enter the following configuration in the /etc/dhcp/dhcpd.conf file. Replace the addresses to match your network card.

   option architecture-type code 93 = unsigned integer 16;
   
   subnet 192.168.124.0 netmask 255.255.255.0 {
     option routers 192.168.124.1;
     option domain-name-servers 192.168.124.1;
     range 192.168.124.100 192.168.124.200;
     class "pxeclients" {
       match if substring (option vendor-class-identifier, 0, 9) = "PXEClient";
       next-server 192.168.124.2;
             if option architecture-type = 00:07 {
               filename "redhat/EFI/BOOT/BOOTX64.EFI";
             }
             else {
               filename "pxelinux/pxelinux.0";
             }
     }
     class "httpclients" {
       match if substring (option vendor-class-identifier, 0, 10) = "HTTPClient";
       option vendor-class-identifier "HTTPClient";
       filename "http://192.168.124.2/redhat/EFI/BOOT/BOOTX64.EFI";
     }
   }

3. Start the DHCPv4 service:

   # systemctl enable --now dhcpd

Procedure

1. Install the DHCP server:

   yum install dhcp-server

2. Set up a DHCPv6 server. Enter the following configuration in the /etc/dhcp/dhcpd6.conf file. Replace the addresses to match your network card.

   option dhcp6.bootfile-url code 59 = string;
   option dhcp6.vendor-class code 16 = {integer 32, integer 16, string};
   
   subnet6 fd33:eb1b:9b36::/64 {
           range6 fd33:eb1b:9b36::64 fd33:eb1b:9b36::c8;
   
           class "PXEClient" {
                   match substring (option dhcp6.vendor-class, 6, 9);
           }
   
           subclass "PXEClient" "PXEClient" {
                   option dhcp6.bootfile-url "tftp://[fd33:eb1b:9b36::2]/redhat/EFI/BOOT/BOOTX64.EFI";
           }
   
           class "HTTPClient" {
                   match substring (option dhcp6.vendor-class, 6, 10);
           }
   
           subclass "HTTPClient" "HTTPClient" {
                   option dhcp6.bootfile-url "http://[fd33:eb1b:9b36::2]/redhat/EFI/BOOT/BOOTX64.EFI";
                   option dhcp6.vendor-class 0 10 "HTTPClient";
           }
   }

3. Start the DHCPv6 service:

   # systemctl enable --now dhcpd6

4. If DHCPv6 packets are dropped by the RP filter in the firewall, check its log. If the log contains the rpfilter_DROP entry, disable the filter using the following configuration in the /etc/firewalld/firewalld.conf file:

   IPv6_rpfilter=no

Procedure

1. Install the HTTP server:

   # yum install httpd

2. Create the /var/www/html/redhat/ directory:

   # mkdir -p /var/www/html/redhat/

3. Download the RHEL DVD ISO file. See All Red Hat Enterprise Linux Downloads.

4. Create a mount point for the ISO file:

   # mkdir -p /var/www/html/redhat/iso/

5. Mount the ISO file:

   # mount -o loop,ro -t iso9660 path-to-RHEL-DVD.iso /var/www/html/redhat/iso

6. Copy the boot loader, kernel, and initramfs from the mounted ISO file into your HTML directory:

   # cp -r /var/www/html/redhat/iso/images /var/www/html/redhat/
   # cp -r /var/www/html/redhat/iso/EFI /var/www/html/redhat/

7. Make the boot loader configuration editable:

   # chmod 644 /var/www/html/redhat/EFI/BOOT/grub.cfg

8. Edit the /var/www/html/redhat/EFI/BOOT/grub.cfg file and replace its content with the following:

   set default="1"
   
   function load_video {
     insmod efi_gop
     insmod efi_uga
     insmod video_bochs
     insmod video_cirrus
     insmod all_video
   }
   
   load_video
   set gfxpayload=keep
   insmod gzio
   insmod part_gpt
   insmod ext2
   
   set timeout=60
   # END /etc/grub.d/00_header #
   
   search --no-floppy --set=root -l 'RHEL-9-3-0-BaseOS-x86_64'
   
   # BEGIN /etc/grub.d/10_linux #
   menuentry 'Install Red Hat Enterprise Linux 9.3' --class fedora --class gnu-linux --class gnu --class os {
       linuxefi ../../images/pxeboot/vmlinuz inst.repo=http://192.168.124.2/redhat/iso quiet
       initrdefi ../../images/pxeboot/initrd.img
   }
   menuentry 'Test this media & install Red Hat Enterprise Linux 9.3' --class fedora --class gnu-linux --class gnu --class os {
       linuxefi ../../images/pxeboot/vmlinuz inst.repo=http://192.168.124.2/redhat/iso quiet
       initrdefi ../../images/pxeboot/initrd.img
   }
   submenu 'Troubleshooting -->' {
       menuentry 'Install Red Hat Enterprise Linux 9.3 in text mode' --class fedora --class gnu-linux --class gnu --class os {
      	 linuxefi ../../images/pxeboot/vmlinuz inst.repo=http://192.168.124.2/redhat/iso inst.text quiet
      	 initrdefi ../../images/pxeboot/initrd.img
       }
       menuentry 'Rescue a Red Hat Enterprise Linux system' --class fedora --class gnu-linux --class gnu --class os {
      	 linuxefi ../../images/pxeboot/vmlinuz inst.repo=http://192.168.124.2/redhat/iso inst.rescue quiet
      	 initrdefi ../../images/pxeboot/initrd.img
       }
   }

   In this file, replace the following strings:

   RHEL-9-3-0-BaseOS-x86_64 and Red Hat Enterprise Linux 9.3

   Edit the version number to match the version of RHEL that you downloaded.

   192.168.124.2

   Replace with the IP address to your server.

9. Make the EFI boot file executable:

   # chmod 755 /var/www/html/redhat/EFI/BOOT/BOOTX64.EFI

10. Open ports in the firewall to allow HTTP (80), DHCP (67, 68) and DHCPv6 (546, 547) traffic:

    # firewall-cmd --zone public \
                   --add-port={80/tcp,67/udp,68/udp,546/udp,547/udp}

    This command enables temporary access until the next server reboot.

11. Optional: To enable permanent access, add the --permanent option to the command.

12. Reload firewall rules:

    # firewall-cmd --reload

13. Start the HTTP server:

    # systemctl enable --now httpd

14. Make the html directory and its content readable and executable:

    # chmod -cR u=rwX,g=rX,o=rX /var/www/html

15. Restore the SELinux context of the html directory:

    # restorecon -FvvR /var/www/html