Dual FAI Configurations

[John G Heim]

it is hard to say what you need to do without knowing specifically what 
problems you are having. What you want to do probably isn't that 
different than what we all have to deal with when upgrading our FAI 
configuration for a new release of our chosen linux flavor. I'm 
currently switching from Ubuntu zesty to artful and I need to make sure 
that the zesty install keeps working while I build the artful configuration.

What I do is to create a class for the new configuration and put changes 
in files named for that class. So for example, if artful requires some 
changes to the contents of /etc/networking/interfaces, I create a file 
named ARTFUL within the fai config for a new version of that file. This 
is generally sufficient for all modifications. In fact, doing anything 
more drastic, like making a copy of the entire config space, only makes 
it harder to eventually integrate the changes into the production space.

So my first recommendation would be to try to use FAI's class feature to 
do your experiments. But if you want to create a whole nother config 
space, you can tell your FAI clients about it by setting the boot 
parameter, FAI_CONFIG_SRC in the pxe boot config file. I manually 
generate my own pxe boot config files instead of using fai-chboot. Just 
never got the hang of it. So what I'd do if I wanted to experiment with 
a whole nother config on a machine or two would be this:

1. Make a copy of the FAI config space. Say, from the default 
/srv/fai/config/ to /opt/fai/config/.
2. Make whatever changes I needed to the files in /opt/fai/config/.
3. Create pxe boot config files for selected machines.
4. In the custom pxe boot file, change 
FAI_CONFIG_SRC=nfs://faiserver/srv/fai/config to 
FAI_CONFIG_SRC=nfs://faiserver/opt/fai/config.

It might not be obvious how to do step #3.   When you pxe boot a 
machine, it first asks the server for a machine matching it's own MAC 
addres.s Then it asks for a file matching it's own IP address in 
hexadecimal. Then it asks for a file matching the first 7 characters of 
it's IP address. Then 6, etc. If you know the MAC or IP address of the 
machines you are experimenting with, you create a file within your pxe 
boot config space for those addresses. I am unclear on the format for 
using MAC address but for IPV4 addresses, it's IP address quad format in 
hexadecimal. So for example, if you want to make a custom pxe boot file 
for a machine with the IPV4 address of 128.64.32.16, it would be 
80402010.  You can make a custom pxe boot file for any machine with an 
IP address in the range, 128.64.32.0/24 by creating a file named 804020.

PS: You probably don't need to create a second nfsroot.


On 01/03/2018 09:53 AM, Itamar Gal wrote:
> Dear FAI Users:
> 
> I'm running into various issues using FAI on a system (an FAI install
> server) which is being managed by a couple of other system
> administrators. I want to experiment with the configuration without
> disturbing the production configuration.
> 
> My thought was to replicate the FAI configuration files inside of my
> ~/local directory and set the relevant FAI environment variables to
> point to sub-directories of ~/local. Is there a way to do this safely?
> If so, which variables do I need to set in my ~/local/etc/fai/fai.conf
> file in order to be certain that I don't cause issues for anyone else?
> There are a few FAI install clients that I have been given for this
> purpose, so it's alright for me to overwrite the PXE files for those
> specific hosts.
> 
> Cheers,
> Itamar
>