FAI_CONFIG_SRC creation and use

Thomas Lange lange at informatik.uni-koeln.de
Wed Oct 14 20:54:29 CEST 2015

>>>>> On Tue, 13 Oct 2015 21:09:01 -0400, George {Skip} F VerDuin <gfv2014 at charter.net> said:

    > I admit to being a bit confused by maybe conflicting
    > information.  My topic is the creation and use of the variable
You are right, this is a bit confusing. Even I had to check to details.

    >   * Is the FAI WIKI VariableTable correct?

    >   * Should the source be /etc/fai/fai.conf instead of fai-make-nfsroot?  Perhaps a dual source?

    >   * Should the comment be removed -- or changed?
No sure yet.

    >   * Perhaps the files are vacant because my setting is identical to the default?

    >   * Should fai-chboot use /etc/fai/fai.conf (or $NFSROOT/etc/fai/fai.conf) for a default setting, and the -u parameter be used to provide an
    >     override only if needed?
This is a good idea.

    >   * Should fai-chboot be added into the "used by" list on the Variables table?

    > I looked to see where m-f-n would write FAI_CONF_SRC and found nothing.
You are right.

FAI_CONFIG_SRC mainly is used by the get-config-dir-* subroutines.
In the past (3.4.8) it was written to $nfsroot/etc/fai.conf when creating the
nfsroot, so you did not need to defined it in the PXE configuration.
Later I changed this, because the value written could be wrong in the
cases where your server has multiple network cards and different host
names for each NIC. And I want the admin to provide the correct value
to the install clients.

These days, you should give the value of FAI_CONFIG_SRC in the
pxelinux configuration by using fai-chboot -u or using fai -s
(for dirinstall or softupdate).

If you call fai on the command line for softupdate it
(FAI_CONFIG_SRC) is still read from /etc/fai/fai.conf. 
The script DEBIAN/40-misc in the simple examples writes the value to
/etc/fai/fai.conf if you have installed this machine using FAI.

If you do an network installation, you will supply its value using
fai-chboot, but it is also read from $nfsroot/etc/fai/fai.conf, but
only if you have put it in there manually. It is not put in there by

Short summary:
By default, you have to specify FAI_CONFIG_SRC on the FAI server.

After a client was installed, it's value is written to
/etc/fai/fai.conf and can be used when doing fai softupdate.

IMO it's a good idea if fai-chboot will try to get the value for
FAI_CONFIG_SRC form /etc/fai/fai.conf. This makes the use of
fai-chboot simpler. But I will not fai-setup or fai-make-nfsroot put
it in there automatically.
The comment in fai.conf should be removed, but I guess we should leave
it in the man page that FAI_CONFIG_SRC can be set there, including the
warning that this will not be copied into the nfsroot.

And yes, I will fix the Wiki variables table.

What's you oppinion? Any more whishes?

regards Thomas

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