特殊:Badtitle/NS100:PXEInstallServer

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Introduction

This will guide you through running an Ubuntu server as PXE install server. You'll need to run a DHCP server on your network, not necessarily this server but you do need one.

Installing needed packages

You'll need to install the following packages inetutils-inetd (previously netkit-inetd), tftpd-hpa (see InstallingSoftware). If this is also going to be your DHCP server, install dhcp server contained in the follwing package: dhcp3-server (see InstallingSoftware)

Configure tftpd-hpa

You'll need to tell tftpd-hpa to start its daemon (which it doesn't by default). To do this, edit the /etc/default/tftpd-hpa file, and make sure that it looks something like this:

#Defaults for tftpd-hpa
RUN_DAEMON="yes"
OPTIONS="-l -s /var/lib/tftpboot"

Then, run the startup script to actually start the daemon

/etc/init.d/tftpd-hpa restart

Configure dhcpd

If your pxe server is also your dhcp server, you'll need something like this in /etc/dhcp3/dhcpd.conf

subnet 192.168.0.0 netmask 255.255.255.0 {
        range 192.168.0.100 192.168.0.200;
        filename "pxelinux.0";
}

If you have an existing dhcp server, you should point it to your pxe server by doing something like the following

subnet 192.168.0.0 netmask 255.255.255.0 {
    <other config here>
    filename "pxelinux.0";
    next-server <pxe host>;
}

Be sure to restart your dhcp server so that the changes take effect

sudo /etc/init.d/dhcp3-server restart

Configure tftpd-hpa

tftpd-hpa is called from inetd. The options passed to tftpd-hpa when it starts are thus found in /etc/inetd.conf The defaults are fine for us, your /etc/inetd.conf should have an entry like this

tftp    dgram   udp    wait    root    /usr/sbin/in.tftpd /usr/sbin/in.tftpd -s /var/lib/tftpboot

(although you may need to edit this file and replace udp with 'udp4', as tftpd-hpa seems to expect an IPv6 address now) Now we'll copy the needed files from the Ubuntu CD

sudo cp -r /media/cdrom/install/netboot/* /var/lib/tftpboot/

If your dhcp server issues correct network info and your pxe clients will have network access, then at this point you will be able to do an Ubuntu install using internet repositories. I want to go a little further however and install everything from the install server as well as customise some of the packages to install.

Install apache

Currently nfs installs aren't well supported (Please correct me if I'm wrong) so we'll install over http. For that we need a webserver on our install server too: install the following package apache (see InstallingSoftware).

Copying Ubuntu files

Create an ubuntu directory under your freshly installed apache's document root and copy all of the contents of the Ubuntu Alternate CD to that directory

mkdir /var/www/ubuntu
cp -r /media/cdrom/* /var/www/ubuntu/

Customising the install

There is a package called system-config-kickstart which is a GUI frontend to creating kickstart files. The kickstart file tells the installer where to get its packages from, what to install and a number of other useful settings. See KickstartCompatibility for more info. This package does not have to be installed on your install server, it can be on a convenient Ubuntu desktop somewhere. Create a custom ks.cfg with system-config-kickstart, be sure to specify HTTP under "Installation Method". Provide the IP of you install server and make the HTTP Directory /ubuntu/ Save the file and copy it to your install server under /var/www/html/ A very minimalist ks.cfg file which only uses the installation files on the install server and asks for all other questions might look like this

install
url --url http://192.168.0.1/ubuntu/

Use your ks.cfg

In order for your network Ubuntu install to use your kickstart file, you have to tell it where to find it. Edit /var/lib/tftpboot/pxelinux.cfg/default and add ks=http://<installserver>/ks.cfg to the append line. It should then look something like this (note that the append line is one line)

label linux
        kernel ubuntu-installer/i386/linux
        append ks=http://192.168.0.1/ks.cfg vga=normal initrd=ubuntu-installer/i386/initrd.gz ramdisk_size=16432 root=/dev/rd/0 rw  --

In Jaunty the default file has been broken up into includes. The append line can be found in /ubuntu-installer/i386/boot-screens/text.cfg

label install
        menu label ^Install (from my http server)
        menu default
        kernel ubuntu-installer/i386/linux
        append ks=http://192.168.0.1/ks.cfg vga=normal initrd=ubuntu-installer/i386/initrd.gz -- quiet

Boot and install

You should now be able to boot another pc on the lan over the network and have it install Ubuntu automagically :) You can vary the tftp and http install points to have multiple versions of Ubuntu available to install on your network.

Using the CD (or .iso) directly

You can also achieve the above without actually copying any files anywhere. You can mount the CD (or the .iso) and then do additional mounts with the --bind option. The advantage is that you can upgrade the CD (or the .iso) without needing to update the install server files. For example, after mounting the CD (or the .iso) to /media/cdrom/, you can mount the ubuntu files to the web directory

mount --bind /media/cdrom/ /var/www/ubuntu/

Similarly, you can do the same with the tftproot:

mount --bind /media/cdrom/install/netboot/ /var/lib/tftpboot/

If you were to create a pxelinux.cfg directory with an appropriate default file, you can mount that over the top of the mounted CD, so that the tftp server gives out your pxelinux.cfg/default file. For example, a pxelinux.cfg directory in ~/pxelinux.cfg could be mounted like this

mount --bind ~/pxelinux.cfg /var/lib/tftpboot/pxelinux.cfg

(Note that in the above example, the actual mount point of the directory would end up as /var/lib/tftpboot/ubuntu-installer/i386/pxelinux.cfg because the pxelinux.cfg is a symlink on the CD (or .iso))

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