Diskless SL4 and SL5 Client

IMPORTANT: This description is valid for SL4 and SL5 only. For SL6 see Diskless SL6 Client.

Requirements

Clients should be able to boot over network (PXE 2.0 boot)
DHCP server which can forward to a TFTP server
TFTP server which stores the kernel and initial ram disk
NFS server which stores the content of the Scientific Linux Live CD/DVD

Setup

You can either run all services (DHCP, TFTP, NFS) on one machine or you can use separate machines. More details about how to setup PXE/DHCP/TFTP can be found at the Syslinux - PXElinux Question page. Here I just give a brief overview.

DHCP Server:
The DHCP server points the client to the pxelinux boot loader (file: pxelinux.0). The Client will get pxelinux.0 over TFTP. Here's a sample entry for an ISC DHCP server:
```
next-server your.tftpserver.com;
filename "/tftpboot/pxelinux.0";
```
Note that if your particular TFTP daemon runs under chroot, you almost certainly should not include the /tftpboot prefix in the filename statement:
```
filename "pxelinux.0";
```
More information can be found here.
TFTP Server:
Install the tftp-server rpm and enable the TFTP server (in /etc/xinetd.d/tftp set "disable = no"). Set the TFTP directory on the server to
```
/tftpboot
```
PXE Linux boot loader:
The necessary file is pxelinux.0. You should find it in the syslinux rpm or take it directly from syslinux:
```
/tftpboot/pxelinux.0
```
The pxelinux configuration files are stored in this directory:
```
/tftpboot/pxelinux.cfg/
```
The (default) PXE configuration file
```
/tftpboot/pxelinux.cfg/default
```
points the client to the kernel, the initial RAM disk and the rest of the operation system. It's possible to have more than one PXE configuration file (depending on IP, subnet, MAC). For more info see the PXE Webpage at syslinux. The syntax of the pxelinux configuration files are equal to the one of syslinux configuration file. See How do I Configure SYSLINUX?. Here is a very simple example for our diskless client:
```
default localboot
prompt 1
timeout 300
display boot.msg

label localboot
  LOCALBOOT 0

label sl5diskless
kernel diskless/sl5/i386/vmlinuz
append nonet nfsroot=168.167.0.2:/master/diskless/sl5/i386/cd initrd=diskless/sl5/i386/initrd.gz init=linuxrc ramdisk_size=50000 root=/dev/ram0 rw
```
The file boot.msg should be in the /tftpboot directory. The label (in this example "sl5diskless") has to be typed in by the client at boot prompt. The path to the kernel (vmlinuz) and to the initial RAM disk (initrd.gz) are given relatively to the /tftpboot directory. Kernel parameters can be passed with the append option. After "append" everything should be on the same line. One important boot parameter is nfsroot. The value of nfsroot tells the client the IP of the NFS server and where he find the copy of the Scientific Linux Live CD. If you like, you can add more boot parameters (for example: noroot, cups=mycupsserver, ..).
The option nonet prevents the system to start the network again.
Please note: On 64bit (at least with SL4 kernel) the "append" line should not exceed a certain length (around 255 characters). Longer lines will end in a kernel panic.

2007-09-21: The auto-detection of the network card has been improved. In addition, you can use the parameter nic= to specify the network card driver directly, for example nic=e1000 will load the e1000 network module.

2009-11-14: Use boot paramter dhcpdelay= to specify the wait time in seconds before doing a dhcp request. The default is set to 8 seconds. Increase this number, if you observe dhcp lease freezes.
Kernel and initial RAM disk:
The diskless client will get the kernel and initial RAM disk over TFTP. Copy from the Scientific Linux Live CD "/boot/vmlinuz" "/boot/initrd.gz" to
```
/tftpboot/diskless/sl5/i386/vmlinuz
/tftpboot/diskless/sl5/i386/initrd.gz
```
Note that the kernel and initial RAM disk are equal for the LiveCD, LiveDVD and MiniLiveCD.
NFS Server:
Install the "portmap" and "nfs-utils" rpms. The NFS server makes the content of the Scientific Linux Live CD/DVD available to the client. Just copy the entire CD or/and DVD into these directories:
```
/master/diskless/sl5/i386/cd
/master/diskless/sl5/i386/dvd
```
For example:
```
mkdir -p /mnt/iso
mount -o loop livecd_SL52_2008-09-17.iso /mnt/iso
mkdir -p /master/diskless/sl5/i386/cd
cp -a /mnt/iso/* /master/diskless/sl5/i386/cd/
```
The directories containing the Scientific Linux Live CD/DVD must be exported read only to the clients. For example in /etc/exports:
```
/master *.my.domain(ro,no_root_squash,async)
```
Finally, start portmapper and nfs server: /etc/initd.d/portmap start; /etc/initd.d/nfs start

Last modified: Friday, 18-Mar-2011 19:29:30 CET by Urs Beyerle