How to network boot the IFL Boot Disk using the PXELINUX boot loader
This is a summary of how to set up a network boot using the pxelinux network boot loader, which is a derivative of syslinux. When booted in this manner, the IFL boot disk will work exactly the same as when booted from other boot media, such as an optical disc or USB flash drive. Additional information on pxelinux can be found at the syslinux web site here:
http://www.syslinux.org/wiki/index.php/The_Syslinux_Project
Booting IFL over the network will require the following:
1. A system BIOS and network adapter that support network booting.
2. A DHCP server on your network configured to point to a TFTP server.
3. A TFTP server on your network to serve the IFL files to the client.
The DHCP and TFTP servers can reside on the same physical machine, although that is not a requirement. In order to work with pxelinux, the TFTP server is currently required to support the "tsize" option, which not all TFTP servers do. One TFTP server available for Linux that supports this option is atpftd (advanced tftp daemon), and it is packaged for Debian and its derivatives, as well as for other Linux distributions.
A brief summary of the steps required are listed below, followed by a more detailed description of each step:
1. Configure the IFL disk (optional)
2. Run makePXE script to create PXE files (from Linux distro or from boot disk)
3. Set up the TFTP server and copy the required files to it
4. Set up the DHCP server (or modify an existing setup)
1. Configure the IFL disk the same as you would for creating a CD/DVD by:
a. editing config.txt (optional)
b. editing ifl.ini (optional)
c. setting up the scripts directory (optional)
d. setting up the wireless directory (optional)
e. setting up the iscsi directory (optional)
Note: This entire step can be skipped if you just want to create a set of PXE files based on the default configuration (iflnet.iso), rather than a customized version.
2. Run the makePXE to create IFL PXE files in pxe directory:
./makePXE -> create PXE files based on the default configuration
./makePXE /c -> create custom version (required to include scripts)
When the /c option is used, makePXE will also present the IFL Boot Media Settings menu from which several options (keyboard, video, etc.) are available to customize the IFL disk, as well as the restore discs it creates. In addition, the options for requiring a console login and changing the default password are presented. All options can be left at their defaults by just pressing <Enter>. At its completion, the pxe directory will be created (if it doesn't already exist from a previous run), and all files required for PXE boot will be in that directory.
Those files are as follows:
efi32 (directory) efi32/ldlinux.e32 efi32/syslinux.cfg efi32/syslinux.efi efi64 (directory) efi64/ldlinux.e64 efi64/syslinux.cfg efi64/syslinux.efi pxelinux.cfg (directory) pxelinux.cfg/default pxelinux.0 menu.txt initrmfs.gz vmlinuz qwerty.ktl azerty.ktl dvorak.ktl qwertz.ktl fgGIod.ktl
These files will need to be copied to the TFTP server once that is set up.
3. Set up the TFTP server and copy the required files to it
This step will depend on which TFTP server you use, but in general it will consist of installing the server and then populating its working directory with the files needed to launch pxelinux and boot IFL. As already mentioned the TFTP server needs to support the "tsize" option, or it will not work with pxelinux. One TFTP server available for Linux that supports this option is atpftd (advanced tftp daemon). The atftpd server is packaged for Debian and its derivatives, as well as for other Linux distributions.
The minimum set of files that the TFTP server requires are listed in step 2 above. These files need to be in the TFTP server's working directory, which often is at /tftpboot, although it can be at another location depending on the server and its configuration.
To summarize, if your TFTP working directory is at /tftpboot, here is an example of what that directory is required to look like for the most basic setup possible:
/tftpboot/: drwxr-xr-x 2 root root 4096 Sep 19 19:26 efi32 drwxr-xr-x 2 root root 4096 Sep 19 19:25 efi64 -r--r--r-- 1 root root 256 Feb 16 14:40 azerty.ktl -r--r--r-- 1 root root 256 Feb 16 14:40 dvorak.ktl -r--r--r-- 1 root root 256 Feb 16 14:40 fgGIod.ktl -r--r--r-- 1 root root 14479378 May 9 13:59 initrmfs.gz -r--r--r-- 1 root root 218 Mar 5 09:55 menu.txt -rw-r--r-- 1 root root 13324 Sep 28 2006 pxelinux.0 drwxr-xr-x 2 root root 4096 Jul 31 2006 pxelinux.cfg -r--r--r-- 1 root root 256 Feb 20 12:40 qwerty.ktl -r--r--r-- 1 root root 256 Feb 20 12:40 qwertz.ktl -r--r--r-- 1 root root 1542640 May 7 10:31 vmlinuz /tftpboot/efi32/: -rw-r--r-- 1 root root 126288 Sep 18 19:17 ldlinux.e32 -rw-r--r-- 1 root root 31 Sep 19 19:25 syslinux.cfg -rw-r--r-- 1 root root 180422 Sep 18 19:17 syslinux.efi /tftpboot/efi64/: -rw-r--r-- 1 root root 144048 Sep 18 19:18 ldlinux.e64 -rw-r--r-- 1 root root 31 Sep 19 19:25 syslinux.cfg -rw-r--r-- 1 root root 182904 Sep 18 19:18 syslinux.efi /tftpboot/pxelinux.cfg: -r--r--r-- 1 root root 297 May 9 13:59 default
The above only describes the most basic set up possible. For example, when the pxelinux.cfg directory contains only the 'default' config file, the IFL boot disk will boot from ANY network-boot-capable machine on your network. Since this may not be desirable, please refer to the pxelinux documentation, as well as their web site, for information on more advanced configurations.
4. Set up the DHCP server. In order for the TFTP server to serve the IFL files over to the client machine, a DHCP server must be configured to:
a. assign an initial IP address to the client on boot
b. tell the client where the TFTP server is located (its IP address)
c. tell the client the path/filename for the pxelinux boot loader on the TFTP server.
These items are typically specified in the configuration file for the DHCP server. The details will, of course, vary depending on which DHCP server is used. The example below shows a minimal config file (dhcpd.conf) for dhcpd, which is a DHCP server commonly used on Linux systems.
option architecture-type code 93 = unsigned integer 16;
subnet 192.168.2.0 netmask 255.255.255.0 {
range 192.168.2.150 192.168.2.199;
default-lease-time 86400;
max-lease-time 86400;
option routers 192.168.2.1;
option ip-forwarding off;
option broadcast-address 192.168.2.255;
option subnet-mask 255.255.255.0;
option domain-name-servers 167.206.251.17, 167.206.251.18, 167.206.251.81;
}
class "pxeclients" {
match if substring (option vendor-class-identifier, 0, 9) = "PXEClient";
next-server 192.168.2.2;
if option architecture-type = 00:00 {
filename "/tftpboot/pxelinux.0";
} elsif option architecture-type = 00:09 {
filename "/tftpboot/efi64/syslinux.efi";
} elsif option architecture-type = 00:07 {
filename "/tftpboot/efi64/syslinux.efi";
} elsif option architecture-type = 00:06 {
filename "/tftpboot/efi32/syslinux.efi";
}
}
Without the next-server and filename, this would just be a standard DHCP server config that would assign a dynamic IP address in the range of 150 to 199 to DHCP clients on the 192.168.2.0 subnet. It also will supply the clients with the default route and dns server IP addresses.
It will still do all of the above for DHCP clients, but the addition of the "next-server" and "filename" lines will cause it to supply network boot clients with the IP address of the TFTP server (next-server), and the path/filename of the pxelinux boot loader on the TFTP server (filename).
The network boot client will use the "next-server" IP address to connect with the TFTP server. Note that the TFTP server and DHCP server can reside on the same machine, and therefore have the same IP address. However, the TFTP server IP address must still always be specified.
The entire sequence of events for the network boot (as configured above) in normal BIOS mode (not UEFI) can be summarized as follows:
1. Client is booted with network boot option selected
2. Client contacts the DHCP server and requests an initial IP address
3. DHCP server supplies the client with:
- the intitial IP address for the client
- the TFTP server IP address (next-server)
- the path/filename for the boot loader on the TFTP server (filename)
4. Client contacts TFTP server and requests boot loader file (pxelinux.0)
5. Client receives and executes pxelinux.0
6. Pxelinux requests its config file (pxelinux.cfg/default in this case)
7. Based on config file, pxelinux requests menu.txt and displays boot menu
8. When boot delay times out (or user presses Enter), pxelinux requests
Linux kernel (vmlinuz), and then the compressed rootfs (initrmfs.gz).
9. Pxelinux boots the kernel, and the boot proceeds normally from there.
Additional information:
~~~~~~~~~~~~~~~~~~~~~~~
For the sake of clarity, the above information describes the requirements in probably the most basic way that it could be implemented. The setup can be fine tuned, for example, to boot a different configuration of the IFL boot disk depending on which machine (based on MAC address) it is booted from. Or it could be configured to prevent booting IFL from certain machines etc.
Note that UEFI PXE boot can take a long time. Be patient.
The following is a list of information sources that you can refer to in order to modify or improve on the very basic configuration described above:
a. The syslinux/pxelinux web site: http://syslinux.zytor.com/pxe.php This web page contains several links to additional information, as well as explanations and examples of how to use pxelinux.
b. The pxelinux.doc and syslinux.doc files are in the help directory. This is the documentation for pxelinux and syslinux. There will also be a man page for syslinux (but not for pxelinux) on any Linux distro where the syslinux package has been installed.
c. http://www.linuxfocus.org/English/September1998/article63.shtml This is an old article, but gives a good, basic explanation of network booting.
d. http://frank.harvard.edu/~coldwell/diskless/ is another article related to network booting