White Box Linux Kickstart Tricks
By Mark Nielsen
- Introduction
- Kickstart walk through
- KickPost trick
- DHCP Stupidity + ksappend Trick
- Boot installation cdrom
- Boot prompt options
- pre and post tricks with wget
- Kickstart tricks with the installer: ssh, bash, and other binaries
- Things to improve
- Conclusion
Introduction
What is White Box? White Box Enterprise Linux is just RedHat's Enterprise Server 3 recompiled from the source RPMs RH provides. Just for kicks, I ran a md5sum comparison between the RH RPMs and WhiteBox RPMs, and in almost all cases, they were identical. Most of the mismatches were related to trademark logos and such or were RPMs that WhiteBox didn't need.White Box is very good for testing and developing since it doesn't require any licenses to use. It also should be considered for production use. Please consider contributing towards the White Box. It is a great project!
What is Kickstart? A means of automating Linux installations and upgrades. First, you create a single configuration file which you put on a floppy disk. Then, you boot your computer from the floppy disk, and it will be configured based on the Kickstart configuration file. If the configuration file is set up right, no questions or prompts are asked during the installation.
So what are the Kickstart tricks? In this article, I'm going to talk about the experience I've gained using Kickstart during the last 6 years and in the course of my work at Nuasis as a Systems Administrator and Programmer.
Please read the following manual before reading the rest of this article.
Kickstart walk through
To me, this is what Kickstart does:- You stick in your boot floppy or boot cdrom.
- It brings you to the isolinux boot prompt (similar to lilo). You can override various settings.
- It boots from the media.
- Installs a shell and the installation software from an image (from the media or the net).
- Tries to get the Kickstart file (ks.cfg), whether it is on the net or on your media.
- Starts the installation.
KickPost trick
There is a neat trick you can do to your ks.cfg file. An undocumented feature which works just fine is the ability to include another ks.cfg file in your ks.cfg file. Put something like this%ksappend https://10.10.10.10/include_this_file.ksinto your ks.cfg file. It will probably also work with another file on the floppy disk or cdrom (but why would you do that?).
DHCP Stupidity + ksappend Trick
By settingappend ip=dhcp
in the isolinux.cfg file of the boot floppy or cdrom, or by typing in
"ip=dhcp" at
the boot prompt, you can boot your computer from a DHCP server for
Kickstarting
purposes. The Kickstart process will also try to use DHCP if you try to get
something from the net and the network settings were not specified.
NOTE: The ip address during Kickstart doesn't have to be the same as
when
the computer reboots after installation.
Besides setting up the network settings, DHCP has the capability of telling your computer where to get the Kickstart file. Here is the problem: The installation program has no way of getting a file except through NFS. Trying to pass a url for a the location of the file won't work. I hate NFS. I have always had problems with it. I prefer to use a web server for Kickstarts.
There are two solutions around this:
- issue the ks=https://somewhere.com/myconfig.ks command at boot
time or in the isolinux.cfg file located on the boot floppy or boot
cdrom.
- Use the kickpost command in a generic Kickstart file.
Thus, the ks.cfg file located on the floppy or cdrom would look like this:
keyboard us lang en_US langsupport en_US network --bootproto=dhcp %ksappend https://10.10.10.10/include_this_file.ks
The isolinux.cfg file would look like
default my_default prompt 1 timeout 600 display boot.msg F1 boot.msg F2 options.msg F3 general.msg F4 param.msg F5 rescue.msg F7 snake.msg label my_default kernel vmlinuz append ip=dhcp initrd=initrd.img kssendmac ksdevice=eth0 lang=en_US label linux kernel vmlinuz append ks initrd=initrd.img label text kernel vmlinuz append initrd=initrd.img text label expert kernel vmlinuz append expert initrd=initrd.img label ks kernel vmlinuz append ks initrd=initrd.img label lowres kernel vmlinuz append initrd=initrd.img lowresThus, you can get around the fact that DHCP can't send a url as the location of your Kickstart file. Also, include_this_file.ks doesn't have to be a text file. It could be a script which prints out the correct Kickstart file based on the ip or MAC address.
Another trick -- let the DHCP server be a DNS server as well.
If your include command is something like this:
%ksappend https://Kickstart.foo/include_this_file.ksThen have DHCP point to itself to be the DNS server, and it can assign an ip address for "Kickstart.foo" (which could be itself). This enables you use an arbitrary server. Practically, you would probably have the dhcp, dns, and Kickstart services run on the same computer.
Boot installation cdrom
If you want to create your own bootable cdrom for installation, then please read the link below. This eliminates the need to use floppies. Another nice thing to do is have your computer eject the cdrom and reboot. (Assuming your rack mount server doesn't reload your cdrom after a reboot) you start the Kickstart, walk away and go to lunch, come back, and your computer is ready to be used. If your computer loads the cdrom after a reboot, then you don't want to do that.https://www.redhat.com/docs/manuals/linux/RHL-9-Manual/install-guide/s1-steps-install-cdrom.html#S2-STEPS-MAKE-CD
A sample isolinux.cfg file for the bootable cdrom would look like this:
default my_default prompt 1 timeout 600 display boot.msg F1 boot.msg F2 options.msg F3 general.msg F4 param.msg F5 rescue.msg F7 snake.msg label my_default kernel vmlinuz append ks=https://10.10.10.10/Kickstart/wb.ks ip=10.10.10.100 gateway=10.10.10.1 netmask=255.255.255.0 dns=10.10.10.50 initrd=initrd.img kssendmac \ ksdevice=eth0 lang=en_US label linux kernel vmlinuz append ks initrd=initrd.img label text kernel vmlinuz append initrd=initrd.img text label expert kernel vmlinuz append expert initrd=initrd.img label ks kernel vmlinuz append ks initrd=initrd.img label lowres kernel vmlinuz append initrd=initrd.img lowres
Now how do you eject the cdrom at the end of the installation? Put reboot as an option in your ks.cfg file if your computer doesn't reload the cdrom after a reboot. Otherwise, put this at the end of the post section in your ks.cfg file. It will basically try to eject every IDE device. If it is a hard drive, who cares, but if is a cdrom, it works. If there is an easy way to do it with a normal command in Kickstart, I missed it.
mkdir /mnt/hda mkdir /mnt/hdb mkdir /mnt/hdc mkdir /mnt/hdd mknod /dev/hda b 3 0 mknod /dev/hdb b 3 64 mknod /dev/hdc b 22 0 mknod /dev/hdd b 22 64 echo '/dev/hda /mnt/hda iso9660,ro 0 0 /dev/hdb /mnt/hdb iso9660,ro 0 0 /dev/hdc /mnt/hdc iso9660,ro 0 0 /dev/hdd /mnt/hdd iso9660,ro 0 0' >> /etc/fstab /mnt/sysimage/usr/bin/eject /dev/hda /mnt/sysimage/usr/bin/eject /dev/hdb /mnt/sysimage/usr/bin/eject /dev/hdc /mnt/sysimage/usr/bin/eject /dev/hdd
Boot prompt options
Read these two docs.- https://www.redhat.com/docs/manuals/linux/RHL-9-Manual/install-guide/ch-bootopts.html
- https://docs.rage.net/system/anaconda-9.0/command-line.txt
Here is a useful trick given the configuration below. The "wb.ks" file on the web server doesn't have to be a text file. If can actually be a script which detects the ip address or MAC address of the computer being Kickstarted and print out the appropriate Kickstart file. Thus, the url for the Kickstart file will stay the same, but the network settings might change. This is useful if you don't have a DHCP server. For Perl, look at the %ENV hash and for Python, look at the os.environ dictionary, to get the ip address or the MAC address. You can also pass arguments in the url if you know what you are doing (for example, pass the host name, and then the perl or python script can determine which Kickstart file to use if it doesn't recognize your ip address or MAC address).
A sample isolinux.cfg file for the bootable cdrom would look like this:
default my_default prompt 1 timeout 600 display boot.msg F1 boot.msg F2 options.msg F3 general.msg F4 param.msg F5 rescue.msg F7 snake.msg label my_default kernel vmlinuz append ks=https://10.10.10.10/Kickstart/wb.ks ip=10.10.10.100 gateway=10.10.10.1 netmask=255.255.255.0 dns=10.10.10.50 initrd=initrd.img kssendmac \ ksdevice=eth0 lang=en_US label linux kernel vmlinuz append ks initrd=initrd.img label text kernel vmlinuz append initrd=initrd.img text label expert kernel vmlinuz append expert initrd=initrd.img label ks kernel vmlinuz append ks initrd=initrd.img label lowres kernel vmlinuz append initrd=initrd.img lowres
pre and post tricks with wget
"wget" is a program which is available during installation time. It can download files over the net. Why is this program useful during Kickstart? In your ks.cfg file, you can use it to download files and put it on your computer. Why is this useful? Well, if you can only install an rpm after the computer has booted, then you can at least download it during installation time. Then, if you are smart enough, you can use a firstboot script to install the rpm the first time the computer comes up.
An example in the ks.cfg file would be:
%post wget -q -O /mnt/sysimage/usr/src/local/sompackage.rpm https://myserver.local/sompackage.rpm
Kickstart tricks with the installer: ssh, bash, and other binaries
Here is an advanced trick which you should only do if you are good at Linux in general. You can basically install any piece of software into your installation program. For example, you can install ssh and ssh to a computer somewhere to you read your email while the computer is being Kickstarted. Sometimes, I am trapped in our Network Operations Center at work, and I am bored watching a Kickstart process, so I use ssh to connect to one of my computers to do something useful.Below, I am going to show you how to install any binary file. You have to be careful about how much space you use up. First off, the installation program uses an image to get a lot of the binaries it uses during installation. An example image is ftp://mirror.physics.ncsu.edu/pub/whitebox/3.0/en/os/i386/RedHat/base/netstg2.img
Now, what you do is modify this image. Here is an example script:
### in case you run this script twice mkdir -p mnt umount mnt rm -rf new_image rm -f netstg2.img ## Get and mount the old image wget -q -O netstg2_orig.img ftp://mirror.physics.ncsu.edu/pub/whitebox/3.0/en/os/i386/RedHat/base/netstg2.img mkdir -p mnt mount -o loop netstg2_orig.img mnt ## Make the new image directory mkdir -p new_image ## rsync the old image to the new image rsync -a mnt/* new_image/ ## rsync a bunch of other stuff over rsync -a /usr/sbin/ssh* new_image/usr/sbin/ rsync -a /usr/bin/ssh* new_image/usr/bin/ rsync -a /usr/bin/rsync* new_image/usr/bin/ rsync -a /usr/bin/nmap* new_image/usr/bin/ rsync -a /usr/bin/scp* new_image/usr/bin/ rsync -a /bin/bash new_image/usr/bin/ ## Make a dependency list -- very crude ldd /usr/sbin/sshd | cut -d ' ' -f3 | cut -d '.' -f1 > List.dep ldd /usr/bin/ssh | cut -d ' ' -f3 | cut -d '.' -f1 >> List.dep ldd /usr/bin/nmap | cut -d ' ' -f3 | cut -d '.' -f1 >> List.dep ldd /bin/bash | cut -d ' ' -f3 | cut -d '.' -f1 >> List.dep ldd /usr/bin/rsync | cut -d ' ' -f3 | cut -d '.' -f1 >> List.dep ldd /usr/bin/scp | cut -d ' ' -f3 | cut -d '.' -f1 >> List.dep ldd /usr/bin/screen | cut -d ' ' -f3 | cut -d '.' -f1 >> List.dep ### execute the perl script to copy over the libraries chmod 755 Copy_Lib.pl ./Copy_Lib.pl ### Make your image. mkcramfs --verbose new_image netstg2.img ### replace netstg2.img on the Kickstart server or cdrom ### with the new one you just created.
Here is the Copy_Lib.pl script:
#!/usr/bin/perl
open(FILE,"List.dep");
my @Lines = <FILE>;
close FILE;
(@Lines) = grep($_ =~ /[a-zA-Z0-9]/, @Lines);
my $Home = "new_image";
foreach my $Line (@Lines) {
chomp $Line;
my $Reverse = reverse $Line;
my (@Temp) = split(/\//, $Reverse, 2);
my $Dir = reverse($Temp[1]);
print `mkdir -vp $Home/$Dir`;
$Command = "rsync -av --ignore-existing $Line* $Home/$Dir/" ;
$Command2 = "rsync -av --copy-links --ignore-existing $Line* $Home/$Dir/";
print "$Command\n";
print `$Command`;
print "$Command2\n";
print `$Command2`;
}
I had trouble changing the default shell to bash during the Kickstart. So, in the %pre section of the ks.cfg file, I entered this command:
cp /usr/bin/bash /then when I clicked on Alt-F2 during installation time, I executed the command:
./bashand I got a good bash shell.
Here is another interesting tidbit, you can also install a service. For example, I tried to get sshd running during a Kickstart. I copied over all the libraries, created a shadow password file, modified /etc/passwd, and actually got sshd to run at Kickstart time automatically. However, when I tried to connect to the computer being Kickstarted, it would crash sshd running on that computer. Crashing sshd didn't affect the Kickstart process. It wasn't important enough for me to get it working, so I gave up.
If I actually could get
to work, I could watch the Kickstart process from my desktop.
I think running an Apache web server should be fine.
I could setup the web server
with a few python scripts. Those scripts would report on the health of
the Kickstart process. That would be cool. Python already exists in the
Kickstart program.
Things to improve
There are only two things in Kickstart which upset me, and either I can live without.- You can't send a host name request to the DHCP server (you
would have to change the boot options of your install media to do this
if it were possible). The only thing the DHCP server can do is match
your computer by its MAC address. With the normal dhclient program
(after you have installed Linux) you can make a host name request, but
not during Kickstart (maybe we should copy over the dhclient
software onto the netstg2.img file and execute dhclient in the
%pre section of the ks file?). If you know how to setup the
dhcp server, it can return the correct fixed ip address even without
knowing the MAC address. It is beyond the scope of this article to
explain how to do that.
- DHCP only lets you get the Kickstart file from an NFS server. This is not a problem with DHCP but with the Kickstart process. It should be able to return a url and the installer should be able to detect the url and download the ks file. It looks like it should be very easy to edit the source code of Anaconda to make it do just that. I briefly looked at the source code and everything is there to download files from a web or ftp server, so it is just a matter of someone doing it.
Conclusion
Overall, I have been pleased with Kickstarting computers. It has proven to be a very powerful tool.I pretty much have no future plans with Kickstart except to contribute to the Yum project by making a Yum server capable of making Kickstart configurations and managing Yum repositories. My dream is to replace RH satellite servers with Yum servers. I would of course use the Python programming language to do this, as it is my favorite programming language and Yum is already written in Python (yeah!).
![[BIO]](../gx/2002/note.png)
Mark Nielsen was enjoying his work at cnet.com as a MySQL DBA, but
is moving to Google as a MySQL DBA.
During his spare time, he uses Python heavily for mathematical and web
projects.
