LET'S PXE!
Now that DHCP is working, it's time to get to the PXE stuff. I got the image file striaght from Ubuntu for my server. I found the files here:http://cdimage.ubuntu.com/netboot/12.04/
I used curl for single files and wget (poorly but somewhat effectively) for an AMD64 build. I figured one build to start and see if I could just get that working even. Curled the pxe version from ubuntu proper (above).
I used the basic format of curl, done as root (probably foolish). In retrospect it
would have been smarter to curl it as a user into a temporary dir and then move it as root or sudo. Anyhow:
curl url/file > file
or you can
curl -O url/file to keep the existing name.
wget -r -l 0 url/ (copies *everything*) but if you point it right at the stuff you
want, you can kill it halfway through, copy over the other things and delete the extra junk which is what I did.
It is probably easier to just curl the 20 or so small boot-screens files than to use wget.
To start with you can put the kernel, initrd and boot-screens directory in
/var/lib/tftpboot/ Go ahead, just dump it in for now.
Assuming you have curled initrd and linux from ubuntu, now edit
/var/lib/tftpboot/pxelinux.cfg/default to look like this:
$ sudo vim /var/lib/tftpboot/pxelinux.cfg/default
# D-I config version 2.0
# include ubuntu-installer/amd64/boot-screens/menu.cfg
# default ubuntu-installer/amd64/boot-screens/vesamenu.c32
include boot-screens/menu.cfg
default boot-screens/vesamenu.c32
prompt 0
timeout 0
label ubuntu distro xxxx
menu default
kernel linux
append initrd=initrd.gz
so, now in /var/lib/tftpboot/ we should have the following, all of it from ubuntu:
$ ls -l
drwxr-xr-x 2 root root 4096 May 12 08:25 boot-screens
-rw-r--r-- 1 root root 21256771 May 12 02:21 initrd.gz
-rw-r--r-- 1 root root 5778968 May 12 02:22 linux
-rw-r--r-- 1 root root 26461 Apr 19 13:22 pxelinux.0
drwxr-xr-x 2 root root 4096 May 12 07:19 pxelinux.cfg
FOR NOW, just read the following - or come back to it later and skip down to:
*fire up your client!*
WHAT THINGS ARE - ubuntu boot-screens
# boot-screens - a directory of text files that show dialogue for OS selection# vesamenu.c32 - an executable that gets the ball rolling: as far I can tell this is a glorified jpg, but you need it.
# f1.txt - f10.txt - text files mostly for errors during load
# *.cfg - primarily text files that allow specific configuration beyond the default screen. You may choose to update the paths in these to accurately reflect where the kernels are. For instance, the path provided by most of these cfg files says something like:
menu default
kernel ubuntu-installer/amd64/blahblahblah/ubuntu64/linux
but you should change them to where the linux file really is. On my server that same line reads:
menu default
kernel ubuntu64/linux
The following detail caused me a fair bit of grief:
RECALL that the path to all files in PXE are considered to start at /var/lib/tftpboot/ REGARDLESS of whether the path begins with / or not.... / does not operate as an absolute path with tftp in this case.
WHAT THINGS ARE - pxelinux.cfg
pxelinux.0 - a modified version of part of an open source project called syslinux. Although pxelinux.0 is primarily a Linux loader, it is capable of loading other operating systems. It operates by using configuration files located on a TFTP server to provide boot instructions.
pxelinux.cfg - the directory where those config files that say which operating system to use (based on the choice you select on your client).
/var/lib/tftpboot/pxelinux.cfg/default - where the magic happens. this is important. this is where you set up what the options for OS will be. Each entry choice has the form:
label <label name>
menu <which menu to use>
kernel <relative path to kernel for this choice from /var/lib/tftpboot/>
append initrd=<relative path to initrd for this chioce from /var/lib/tftpboot>
So, using my example of how I configured my directories and where I put my OS choices as indicated previously in the directory structure sample, the menu choice for the 64 bit Ubuntu 14.04 OS looks like this:
label 64 bit ubuntu 14.04
menu default
kernel 14ubuntu64/linux
append initrd=14ubuntu64/initrd.gz
as many as you want, just configure them here and put the corresponding files in the matching locations.
FIRE UP YOUR CLIENT!
Since you have enabled DHCP you should just be able to plug your client box into your network, hit f12, select your OS and follow the instructions. If it were that easy, the text would have ended by now
C L I E N T
You need a box that is pxe capable, I worked with a lot of ancient equipment and not all of it had that capability. Anything 64 bit is probably a safe bet, but check the bios to ensure your client can do it.
A couple of different difficulties you may run into with your client:
- is your client pxe capable?
- is your client configured to pxe?
* perhaps you have to hit f12?
* have you adjusted the bios to try pxe first rather than look to the drives?
* do you need to adjust the NIC settings in the bios?
- can you tail the logs on the pxe server to verify that your client and server are talking?
* on my server (batman): $ tail -f /var/log/syslogs > May 12 07:33:48 batman dhcpd: DHCPDISCOVER from 00:1a:xx:xx:xx:xx via eth0
> May 12 07:33:49 batman dhcpd: DHCPOFFER on 1xx.2xx.xxx.xxx to 00:1a:xx:xx:xx:xx via eth0
> May 12 07:33:52 batman dhcpd: DHCPREQUEST for 1xx.2xx.xxx.xxx (1xx.2xx.xxx.xxx) from 00:1a:xx:xx:xx:xx via eth0
> May 12 07:33:52 batman dhcpd: DHCPACK on 1xx.2xx.xxx.xxx to 00:1a:xx:xx:xx:xx via eth0 - if you don't see this sort of conversation between your client and the server, then perhaps:
* your client isn't plugged into a swtich port that is on the same vlan as the server
* other plug problems, bad cable
* dhcp not configured correctly on the server
* the switch is ancient and is S... L...O... W... . . . . . make sure the light has a chance to turn green. This happened to me, really.
SERVING MORE THAN ONE OS
If you want to have your server host multiple OS there are a variety of ways to go about this. I preferred putting all my different OS kernels and initrd files into their own directories - a little more work but ultimately nice and clean. Alternatively you could give each of them a unique identifier and dump it all into one directory. The reality is that how the client knows where they are and what to load is based in the config files.
that being said here is what my /var/lib/tftboot dir looks like
/var/lib/tftpboot$ ls -l
drwxr-xr-x 2 root root 4096 May 8 04:19 12ubuntu32
drwxr-xr-x 2 root root 4096 May 8 03:52 12ubuntu64
drwxr-xr-x 2 root root 4096 May 12 02:22 14ubuntu64
drwxr-xr-x 2 root root 4096 May 12 07:06 boot-screens
drwxr-xr-x 2 root root 4096 May 8 02:46 coreos
-rw-r--r-- 1 root root 26461 Apr 19 13:22 pxelinux.0
drwxr-xr-x 2 root root 4096 May 12 07:19 pxelinux.cfg
in each directory is its own initrd and kernel:
/var/lib/tftpboot/14ubuntu64$ ls -l
-rw-r--r-- 1 root root 21256771 May 12 02:21 initrd.gz
-rw-r--r-- 1 root root 5778968 May 12 02:22 linux
WHERE IS EVERYTHING AGAIN?
dhcp activity: server /var/log/syslog dir
dhcp leases: server /var/lib/dhcp dir
dhcp config: server /var/lib/dhcp/dhcpd.conf file
dhcp service: server isc-dhcp-server service
hosts you know: server/client /etc/hosts file
pxe config: server /var/lib/tftpboot/pxelinux.cfg/default file
OS options: server /var/lib/tftpboot/MY_OS/ (kernel and initrd)
TREMENDOUS THANKS!
blkperl - my primary mentorhttps://help.ubuntu.com/community/PXEInstallServer
http://blog.alainodea.com/en/ipxe-smartos
Also good:
http://askubuntu.com/questions/412574/pxe-boot-server-installation-steps-in-ubuntu-server-vm
https://help.ubuntu.com/community/UbuntuLTSP/StaticIPsWithDHCP
https://help.ubuntu.com/community/isc-dhcp-server
tailing the logs can be helpful too: sudo tail -f /var/log/syslog
Additional hugely complicated reading:
http://www.openbsd.org/faq/faq6.html
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