Jan 292012
 

SystemRescueCD is very useful to have on hand for those issues that come up at the worst times. Instead of having to dig for that USB key or CD that SystemRescueCD is on, I’ve setup my PXE server with SystemRescueCD to save time on having to find where I’ve put the CD. It also means that when SystemRescueCD is updated, all I need to do is update the files on my PXE server instead of having to burn a new CD or install it again on a USB key which means less clutter for me which is always good.

The only downside to booting over the network is the time it takes to boot if you’re still on good ol’ 100 megabit “Fast” Ethernet as SystemRescueCD weights in at just over 300 megabytes, which also means the system that you’re network booting on must have at least 512 megabytes of ram in order to network boot SystemRescueCD as all the data is stored in RAM when you networkboot.

Anyways, onto the nitty grittys.


Step 1 – Getting the SystemRescueCD files

We need the ISO file that contains the files we will need to PXE boot SystemRescueCD which can be downloaded from here.
Once we have the ISO file, we need 4 files off the ISO file, which are –

  • initram.igz – this is the initial ramdisk that SystemRescueCD uses to boot
  • rescuecd – This is the kernel that SystemRescueCD uses, however there are other options that can be used.
  • sysrcd.dat – This contains the squash file system that becomes the root filesystem for SystemRescueCD
  • sysrcd.md5 – This is the signature file for SystemRescueCD, and isn’t actually needed, but good idea to have.

Once we have these 4 files, we need to place them onto our PXE server. I have used the directory /tftpboot/srcd for my files on the server.

Step 2 – Configuring the PXE Server

We will need to edit the file that contains the configuration for the PXE server. If you have been following my PXE Server guide then the file is called default in the pxelinux.cfg directory.
Using your favourite text editor, add the following lines to the configuration file –

LABEL SRCD
MENU LABEL SystemRescueCD 2.4.1
kernel srcd/rescuecd
append initrd=srcd/initram.igz netboot=tftp://10.1.1.1/srcd/sysrcd.dat

The last two lines will need customisation to your setup if you use a different kernel, or the IP address of your PXE server is different, as will the path for the kernel, initram and netboot parameters.

Once the configuration file is updated, you should now be able to boot SystemRescueCD over the network with little difficulty, however if the network has some issues you may find it will take a little while as the TFTP protocol sends data over UDP which does not support resending corrupted data.

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Jun 132011
 

Hi All,

I’ve recently been playing around with some small distributions so I can setup a tiny webcam server – no luck there yet, but I thought I’d post up how to boot Puppy over PXE as I tried that out while messing around.

Step 1 – Getting Puppy

So first thing we need to do, is to get Puppy Linux from here

wget http://distro.ibiblio.org/pub/linux/distributions/puppylinux/puppy-5.2.5/lupu-525.iso

Wget is my weapon of choice here, so the above command will download the ISO file into the current directory. I am logged in as root to set everything up so it has downloaded the iso to /root/.

After we get the ISO file, we need to extract a few files from the ISO so we can use them to boot over PXE.

mount -o loop lupu-525.iso /mnt

With the above command, we mount the ISO from the current directory onto /mnt so we can copy the files off the ISO.
Once it is mounted, we will need 3 files off the ISO:
initrd.gz
vmlinuz
lupu_525.sfs

mkdir /tftpboot/puppy/
cp /mnt/initrd.gz /tftpboot/puppy/
cp /mnt/vmlinuz /tftpboot/puppy/
cp /mnt/lupu_525.sfs /tftpboot/puppy/

With those commands, we create a directory to store the files in, and copy them over.

Step 2 – Setting it up

We will need to pack lupu_525.sfs into the initrd image for this to work as the livecd expects it to be somewhere on the boot media but we don’t have any boot media as we are booting over the network.

So what we do is make a folder so we can modify the initrd –

mkdir /tftpboot/puppy/temp

Change to that directory

cd /tftpboot/puppy/temp

Then we will extract the contents of the initrd.

zcat /tftpboot/puppy/initrd.gz | cpio -i -H newc -d

Now the contents of the initrd are in /tftpboot/puppy/temp
We’ll move the lupu_525.sfs file into the temp folder –

mv /tftpboot/puppy/lupu_525.sfs /tftpboot/puppy/temp

Then we’ll repack it up into a new initrd.gz file by running this command while inside the temp directory –

find | cpio -o -H newc | gzip -4 > ../newinitrd.gz

Now we have our new initrd.gz file, we can setup the pxelinux config file with a new menu item.

Step 3 – Setting up pxelinux.cfg

So now we will need to add the following codeblock to /tftpboot/pxelinux.cfg/default


LABEL Puppylinux
MENU LABEL Puppy Linux 5.2.5
kernel puppy/vmlinuz
append initrd=puppy/newinitrd.gz

Notice we have used the name of the newinitrd.gz file as that is the one we will need to boot from in order for Puppylinux to get the lupu_525.sfs file.

Once you have updated the configuration file, you are now ready to boot Puppy Linux 5.2.5 !

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Jun 082011
 

A continuation of this post.

You can also create machine specific configuration files by naming the file the same as the mac address but replacing the colons ( : ) with dashes ( – ) and adding a 01 to the front to signify that this is an ethernet address..
So 00:15:af:69:31:79 becomes 01-00-15-af-69-31-79.

This is also the “BOOTIF” that you see on the previous screenshot.

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May 262011
 

Hi All,

Recently I decided to update my Lenovo laptop’s BIOS, but I didn’t have any blank CDs to burn the update iso onto.
Now that I have my PXE server running though, I can boot the ISO over PXE !

So first step was to grab the ISO file from the Lenovo website.
Once you have the ISO file, you will need to copy it to your /tftpboot/ directory, and depending on your style, a subdirectory. I have my ISO file in a subdirectory called lenovo, so the full path would be /tftpboot/lenovo.

Next up is to modify the pxelinux.cfg/default file to add the lines you will need for the ISO file.
Now you will need the memdisk kernel before you add these lines.
If you haven’t already found it, it can be found in the /usr/lib/syslinux/ directory.
I have put memdisk into the boot subdirectory for this exercise, and then added the following block to my default file.


label LenovoBios
menu label Lenovo BIOS 66ET60WW
kernel boot/memdisk
append initrd=lenovo/66et60ww.iso iso

You’ll have to replace the ISO file name with the file that you downloaded, but you should be able to boot off that and update the BIOS that way as I’ve managed to do it with my Lenovo 3000 N200 laptop.

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May 192011
 

Hi All,

I’m in the process of setting up PXE for some computers of mine, but I wanted them to have a separate configuration file as they do not have the power to run some of the other options, so I don’t want them to show up. I didn’t want to define specific IP addresses for the computers either or use IP specific configuration files as IP address may change.

So, what I did is to make a configuration file with the SYSUUID as the filename, since the SYSUUID is based off the mac address of the computer.
Then when it loads, the computer will boot off the SYSUUID configuration file instead of the default one.
You can find the SYSUUID on the boot page when a computer is booting from the network.

The SYSUUID is outlined in red, and quite long, but if a file is named that then the computer will boot off it, as that one is currently doing.

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May 172011
 

Hi All,

In my previous post regarding booting Tiny Core Linux over PXE, we were booting a premade image that did not have much installed by default.
In this post, we will remaster the image into something usable that we can boot off by extracting all the files that we need and merging the directories then repacking it all into one. One of the advantages of doing it this way is that it lets you modify all the files in the root file system before you repack it all up.

What we will need to do is to get the tcz files for the applications we want to install, and merge them into the default tinycore.gz image. This will result in a larger tinycore.gz file but when the image is booted, applications will be pre-installed. This can be useful for diskless workstations in an office or netcafe for example.

So, onto the hard parts.


Step 1 – Getting the TCZ files

Ok, so once we’ve decided what software we want, we will need the TCZ files for the software we want.
This Site has a list of all the software we need and their dependencies, though it’s a bit tedious to download every single file as I haven’t found any other way to download what we need.

So, I took a shortcut.
Boot up Tiny Core Linux either using a virtual machine or real machine using PXE or some other boot media.
Install all the software you want via the app manager, and then all the files you need are in /tmp/tce/optional/.
To do this, you will need an internet connection on the computer that you’re booting Tiny Core on.

For me, I will install Firefox, OpenSSH (SSH Client and server), conky, pci-utils, and util-linux-ng, but you can choose what you want to install.
After I have installed the software, all the tcz files I need will be in /tmp/tce/optional/ and should look something like this :

After all the files are there, we will need to transfer them to a different computer to do the remastering.
In this case, I will be transferring them to my PXE server which will be doing the remastering.

Step 2 – Uncompressing Everything

Once we have all the tcz files where we need them, we will need to uncompress them as they are all compressed using squashfs.
We will need to install some additional tools to do that, namely squashfs-tools.

apt-get install squashfs-tools

Once that is installed, we can unsquash all the files so that we can access them like a normal filesystem.
I’ve written up a little script to do it all for me in this case :


#!/bin/bash
for i in $( ls ); do
if [ ! $i == "unsquashall.sh" ] && [ -f $i ]; then
unsquashfs -f $i
fi
done

I’ve named this unsquashall.sh, and have put this into the directory where all the tcz files are.
If you copy and paste this into a .sh file, don’t forget to make it an executable file by running :

chmod +x unsquashall.sh

After you run unsquashall.sh, you will have a directory called squashfs-root which will contain the contents of all the tcz files.

What you will also need, is the core of Tiny Core, the tinycore.gz file. This is a gzipped cpio file which contains the main file system of Tiny Core Linux.
You will want tinycore.gz in it’s own directory when you extract it to make things easier, I have used /tftpboot/tc/temp for that.
To extract tinycore.gz, you will need to run this command as root, or alternatively use sudo before this command.


zcat tinycore.gz | cpio -i -H newc -d

Step 3 – The Merge

Once you’ve extracted the contents, you should see something similar to this :

Looks just like the root file system of a Linux distribution doesn’t it ?
Now, we need to copy the contents of that squashfs-root directory that we created before into this directory.
I have the squashfs-root directory in the /tftpboot/tc/tcz directory, so the command I will be running is :


cp -Rp /tftpboot/tc/tcz/squashfs-root/usr/ /tftpboot/tc/temp/

Step 4 – Repacking Everything

After doing that, we need to repack everything up.
I have made another script for that –


#!/bin/bash
find | cpio -o -H newc | gzip -2 > /tftpboot/tc/tc.gz

Once again, you will need to make the file executable and it should be placed in /tftpboot/tc/temp/.
Once run, this script will create the tc.gz file in /tftpboot/tc which will replace the tinycore.gz file.
I have also copied the kernel bzImage from the iso file into the /tftpboot/tc directory also.

Step 5 – Configuring PXE

Once all that is done, we now need to reconfigure pxe to boot the new Tiny Core initrd file.


LABEL tinycorerm
MENU LABEL Tiny Core 3.6 Remaster
kernel tc/bzImage
append initrd=tc/tc.gz

Should look something like :


So when you boot up the remastered Tiny Core, you should see Firefox in the dock – that’s if you chose to install it.

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May 162011
 

Hi all,

I’ve had a play around with Tiny Core Linux recently, and I’m amazed at how they have fit in a window manager and some basic utilities into 10 megabytes.
You start off with a very basic system, consisting of only the Window Manager, and Application manager.

With Tiny Core Linux, you install applications by downloading the tcz files, and loading them via the Application Manager. Alternatively you can remaster the default image to add more applications, which I will also cover later on as it can work extremely well in conjunction with netbooting.

So without further ado, onto the simple process of PXE booting Tiny Core !


Step 1 – Getting Tiny Core

As always, we need to get the files we need first before we can boot from them.

wget http://distro.ibiblio.org/tinycorelinux/3.x/release/tinycore-current.iso

We will grab the ISO file first, and then we will need to extract the files we need from the ISO.
Now from here, we have 2 options.
We can mount the ISO image and boot straight from that to achieve a basic system, or we can extract the files so that we can use them later on to create a remastered image for multiple use situations, e.g. net cafe or diskless workstations.

In this post, I will go with the former option of just mounting it and booting from that.
I will cover the extraction of files and remastering in the next post.

Step 2 – Mounting the ISO

We now need to create a directory on our tftp server so we have a place to mount the ISO file.

mkdir /tftpboot/tinycore

After we’ve done that, we can now use the mount command to mount the ISO in loopback mode.

mount -o loop tinycore-current.iso /tftpboot/tinycore

Once that’s mounted, we can now do a ls in /tftpboot/tinycore to see what’s in there.

ls /tftpboot/tinycore

Should see something similar to this :

This is the contents of the ISO file, which should contain just a ‘boot’ folder.

Step 3 – Configuring the boot menu

So once we have the files where we need them, we can now edit the pxelinux.cfg/default file to include Tiny Core.
We will need this codeblock in there :


LABEL tinycore
MENU LABEL Tiny Core 3.6
kernel tinycore/boot/bzImage
append initrd=tinycore/boot/tinycore.gz

So it should look something similar to this if you have been following my blog up until now :

Once that is complete, when you boot from the network, you should see Tiny Core 3.6 as an option in the menu now.

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