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__NOTOC__
This is the third page of a five part tutorial on cloning worker nodes with Udpcast.  The full tutorial includes

* [[Cloning Worker Nodes]]
* [[Udpcast Cloning: Preparing the Udp-sender]]
* [[Udpcast Cloning: Preparing the DHCP Server for PXE Booting]]
* [[Udpcast Cloning: Troubleshooting PXE Booting]]
* '''[[Udpcast Cloning: Imaging using Udpcast]]'''

<pre>
kestrel:~# udp-sender -f /dev/sda
Udp-sender 2004-05-31
Using mcast address 232.168.1.201
UDP sender for /dev/sda at 192.168.1.201 on eth0 
Broadcasting control to 192.168.1.255
New connection from 192.168.1.202  (#0) 00000009
Ready. Press any key to start sending data.
New connection from 192.168.1.205  (#1) 00000009
Ready. Press any key to start sending data.
New connection from 192.168.1.203  (#2) 00000009
Ready. Press any key to start sending data.
New connection from 192.168.1.207  (#3) 00000009
Ready. Press any key to start sending data.
</pre>

== Setting the Nodes to PXE Boot ==
All of the nodes that will be receiving an image, plus the node that will be sending its image, need to be configured to PXE boot.  This should be a setting in the BIOS.  It might be listed under boot options, PCI options, advanced options, or something else.  Generally you're looking for something along the lines of "Onboard NIC ROM", "PXE Boot", or "Network Boot", and you want that setting to be enabled.

=== Configuration for the Nodes Receiving an Image ===
The next time that node is restarted, it should first look to the network for a DHCP server with a PXE image to boot from before booting from its own hard drive.  If you start up one of the nodes, the udpcast image will load and then you'll be prompted to answer a series of questions.  Rather than having to answer these questions again for each node, the <code>pxelinux.cfg/default</code> can be edited to automatically supply them.

You can do this by writing down your answers for each of the questions or manually editing the file using the documentation on the [http://udpcast.linux.lu/bootloader.html#pxe Udpcast site] (see "The configuration file" header).  Then update the file <code>/var/lib/tftpboot/pxelinux.cfg/default</code>.  This will be the file that all of the receivers use for configuration (we'll create the sender one in a moment).

Commands need to be added to the end of the line beginning with

:<code>append load_ramdisk=1 initrd=initrd root=01:00</code>

Mine ended up being this:

<pre>
default linux
label linux
  kernel linux
  append load_ramdisk=1 initrd=initrd root=01:00 auto=yes lang=US kbmap=US netmodule=AUTO netmodparm= dhcp=yes port=9000 enableDiskmodule=yes diskmodule=AUTO diskmodparm= disk=/dev/sda compr=none umode=rcv udpcparam=
  ipappend 1</pre>

*<code>auto=yes</code> means that the user should not be prompted for any parameters already specified.
*<code>lang</code> is the language
*<code>kbmp</code> is the keyboard map
*<code>netmodule=AUTO</code> means the network interface should automatically be detected
*<code>netmodparm</code> are parameters for the network interface.  Even though there aren't any, the parameter needs to be entered or the computer booting with this configuration will prompt the user for them.
*<code>dhcp=yes</code> means that the nodes should use their information on IP, gateway, etcetera from the DHCP server (you can specify your own instead if you need to).
*<code>port=9000</code> specifies that the transfer will occur on port 9000 (the default, but again it needs to be entered so it doesn't prompt)
*<code>enableDiskModule</code> needs to be yes, since it specifies if the drivers for the hard drive should be loaded
*<code>diskmodule</code> is the specific driver for the disk.  AUTO causes it to automatically detect them.
*<code>disk</code> specifies what is to be imaged.  In my case, the hard drive to be imaged is <code>/dev/sda</code>.  (To determine yours, use <code>fdisk -l</code>.)
*<code>compr</code> is the compression; it's fine not to use any.
*<code>umode</code> can be <code>snd</code> (send) or <code>rcv</code> (receive).  This is the file all the receivers will take, so use <code>rcv</code>.
*<code>udpcparam</code> are any additional parameters.  Again, there are none, but unless it is specified, the prompt will come up.

=== Configuration for the Sending Node ===
The sending node needs a different configuration file to tell it to send the image of its hard drive rather than receiving one.  The <code>default</code> file is used by any PXE booting machines without their own individual configuration files.  Rather than having the udp-sender use the default file, we'll specify its own for it.  The first place a machine looks for a configuration file is a file that starts with 01- followed by its MAC address specified with dashes.  For instance, a machine with a MAC address of 00:0e:0c:4d:a4:b2 looks for a file named <code>01-00-0e-0c-4d-a4-b2</code>.

Create this file by copying the default one:

:<code>'''cp default 01-<your sender's MAC address>'''</code>

Then we need to update the file with the correct parameters for the sender.  Specifically, the <code>umode</code> parameter needs to be changed from <code>rcv</code> to <code>snd</code>.  <code>udpcparam=</code> also needs to be changed to <code>udpcparam=broadcast</code>.

== Links ==
* [http://syslinux.zytor.com/ The SYSLINUX Project site]
* [http://udpcast.linux.lu/ The UDPCast site]