Setting Up an Installation Server

This appendix is intended for users with previous Linux experience. If you are a new user, you may want to install using minimal boot media or the distribution DVD instead.

PXE Installation Overview

Preboot Execution Environment, or PXE, is a techonology that allows computers to boot directly from resources provided over the network. Installing Fedora over the network means you don’t have to create media, and you can install to multiple computers or virtual machine simultaneously. The process involves a number of components and features working together to provide the resources required.

PXE-capable computer

Most modern computers have the capability to network boot. Typically, a function key pressed during boot will bring up a boot selection menu. In environments designed for unattended administration, systems will often be configured to first attempt booting from the network, then boot from local storage, and the installation server is configured to only offer the installation when required. Your computer’s manual will provide specific instructions on setting boot priorities.

DHCP Server

When a system requests an address during network booting, the DHCP server also provides the location of files to boot. A network should have only one DHCP server.

TFTP Server

Because the pre-boot environment is very simple, files must be provided in a very simple way. Trivial File Transfer Protocol, or TFTP, provides the system with the bootloader required to continue the installation process.

Bootloader

Because the job of booting an operating system is too complex for the pre-boot environment, a bootloader is used to load the kernel and related files. It also provides configuration information to the installer, and can offer a menu to select from different configurations.

Kernel and Initramfs

The kernel is the core of any Linux operating system, and the initramfs provides the kernel with required tools and resources. These files are also provided by tftp.

Package repository

A Fedora repository must be available for the installation. The example in this section uses the public Fedora mirrors as the repository source, but you can also use a repo on the local network provided by NFS, FTP, or HTTP. Repositories can be configured using the inst.repo= boot option; see Specifying the Installation Source for details.

DHCP Server Configuration

Installing and configuring dhcpd
  1. Install the dhcp server package.

    # dnf install dhcp
  2. Create a simple configuration for the dhcp server at /etc/dhcp/dhcpd.conf

    subnet 192.168.1.0 netmask 255.255.255.0 {
    authoritative;
    default-lease-time 600;
    max-lease-time 7200;
    ddns-update-style none;
    
    option domain-name-servers 192.168.1.1;
    option routers 192.168.1.1;
    
    }
  3. Test your configuration and address any problems you discover.

    systemctl start dhcpd
    journalctl --unit dhcpd --since -2m --follow
  4. Add entries to point clients to their bootloader and the server that provides it to your subnet configuration in /etc/dhcp/dhcpd.conf. Because DHCP clients provide the server with identifying information along with their address request, BIOS clients and UEFI clients can each be directed to the correct bootloader.

    # refer to RFC4758 for possible arch option values
    option arch code 93 = unsigned integer 16;
    
    subnet 192.168.1.0 netmask 255.255.255.0 {
    if option arch = 00:07 {
    filename "uefi/shim.efi";
    } else {
    filename "pxelinux.0";
    }
    
    next-server 192.168.1.2;
    
    ...
  5. Restart the dhcp service to check the configuration and make changes as needed.

    systemctl restart dhcpd
    journalctl --unit dhcpd --since -2m --follow

Installing the tftp server

Installing the tftp server
  1. Install the tftp server package.

    # dnf install tftp-server
  2. Start and enable the tftp socket. systemd will automatically start the tftpd service when required.

    # systemctl start tftp.socket
    # systemctl enable tftp.socket

Providing and configuring bootloaders for PXE clients

Getting the bootloader files
  1. Get the syslinux bootloader for BIOS clients.

    1. Install the syslinux package.

      # dnf install syslinux
    2. Create a directory for the bootloader files, and make them available there.

      # mkdir -p /var/lib/tftpboot/pxelinux.cfg
      # cp /usr/share/syslinux/{pxelinux.0,vesamenu.c32,ldlinux.c32,libcom32.c32,libutil.c32} /var/lib/tftpboot/
  2. Get the bootloader files for UEFI systems

    1. Install the shim and grub2-efi packages. If your server is a BIOS system, you must install the packages to a temporary install root. Installing them directly on a BIOS machine will attempt to configure the system for UEFI booting and cause problems.

      # dnf install shim grub2-efi --installroot=/tmp/fedora --releasever 26
    2. Create a directory for the bootloader files, and make them available there.

      # mkdir -p /var/lib/tftpboot/uefi
      # cp /tmp/fedora/boot/efi/EFI/fedora/{shim.efi,grubx64.efi} /var/lib/tftpboot/uefi/
Configuring client bootloaders
  1. Create a boot menu for BIOS clients at /var/lib/tftpboot/pxelinux.cfg/default.

    default vesamenu.c32
    prompt 1
    timeout 600
    
    label linux
    menu label ^Install Fedora 26 64-bit
    menu default
    kernel f26/vmlinuz
    append initrd=f26/initrd.img inst.stage2=http://download.fedoraproject.org/pub/fedora/linux/releases/26/Server/x86_64/os/ ip=dhcp
    
    label server
    menu label ^Install Fedora 26 ( Minimal Image )
    menu default
    kernel f26/vmlinuz
    append initrd=f26/initrd.img inst.stage2=http://download.fedoraproject.org/pub/fedora/linux/releases/26/Server/x86_64/os/ ip=dhcp ks=https://example.com/fedora/kickstarts/minimal.ks
    
    label rescue
    menu label ^Rescue installed system
    kernel f26/vmlinuz
    append initrd=f26initrd.img ip=dhcp root=live:http://download.fedoraproject.org/pub/fedora/linux/releases/26/Server/x86_64/os/LiveOS/squashfs.img rescue
    
    label local
    menu label Boot from ^local drive
    localboot 0xffff
  2. Create a boot menu for UEFI clients at /var/lib/tftpboot/pxelinux/uefi.

    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
    
    menuentry 'Install Fedora 64-bit'  --class fedora --class gnu-linux --class gnu --class os {
    	linuxefi f26/vmlinuz ip=dhcp inst.repo=http://download.fedoraproject.org/pub/fedora/linux/releases/26/Server/x86_64/os/
    	initrdefi f26/initrd.img
    }
    
    menuentry 'Install Fedora 26 Server'  --class fedora --class gnu-linux --class gnu --class os {
    	kernel f26/vmlinuz
    	append initrd=f26/initrd.img inst.repo=http://download.fedoraproject.org/pub/fedora/linux/releases/26/Server/x86_64/os/ ip=dhcp ks=https://git.fedorahosted.org/cgit/spin-kickstarts.git/plain/fedora-install-server.ks?h=f21
    }
    
    menuentry 'Rescue installed system'  --class fedora --class gnu-linux --class gnu --class os {
    	kernel f26/vmlinuz
    	append f26/initrd=initrd.img root=live:http://download.fedoraproject.org/pub/fedora/linux/releases/26/Server/x86_64/os/LiveOS/squashfs.img rescue
    }

Getting the kernel and initrd

Downloading the kernel and initrd
  1. Create a directory for the files.

    # mkdir -p /var/lib/tftpboot/f26
  2. Download the kernel.

    # wget http://download.fedoraproject.org/pub/fedora/linux/releases/26/Server/x86_64/os/images/pxeboot/vmlinuz -O /var/lib/tftpboot/f26/vmlinuz
  3. Download the initrd

    # wget http://download.fedoraproject.org/pub/fedora/linux/releases/26/Server/x86_64/os/images/pxeboot/initrd.img -O /var/lib/tftpboot/f26/initrd.img

Providing repositories

The examples in this section use the public Fedora mirrors as the package source. For faster installations, installing to many systems, or more isolated environments, you may wish to maintain a local repository.

Fedora Infrastructure maintains instructions for a configuring a local mirror at https://fedoraproject.org/wiki/Infrastructure/Mirroring. The preferred method for providing repositories is via HTTP, and you can refer to the Fedora System Administrator’s Guide, available at http://docs.fedoraproject.org/, to configure httpd.

Advanced network installations with Cobbler

For more complex environments, Fedora offers the cobbler installation server. Tasks like managing kickstart configurtations, coordinating repositories, maintaining dns records, dhcp servers, and even puppet manifests are effectively automated by cobbler.

While levaraging all of the features provided by cobbler can be relatively simple, the full functionality of this powerful tool is too broad to be documented in this guide. The cobbler community provides excellent documentation at http://www.cobblerd.org/manuals/2.6.0/ to accompany the packages in the Fedora repository.