Tip: Run a script after FAI install

[John G Heim]

Well, it's not really to the point. Maybe my example was bad but there 
are lots of other reasons one might want to run a script after the 
install is finished. Actually, the reason this came up is that I want 
the linux cli screen reader to run on the first boot and then get 
disabled. But I just added it to the things my fai setup does after the 
first reboot.




On 1/10/19 6:55 AM, Brian Kroth wrote:
> You can configure the nfsroot with your ldap configs so you can have 
> them available during fai. I used this (at another UW department) for 
> rescue consoles to support natural logins from admins.
> 
> As far as the sudo config, why not just copy a sudoers (.d) snippet down 
> that references the user during fai/config management time? It can still 
> reference an ldap user without them being available yet. They don't need 
> to be in the local sudo group to privelege them. You can also add host 
> match restrictions if you want. It's quite customizable.
> 
> On Thu, Jan 10, 2019, 00:29 Martin Krämer <mk.maddin at gmail.com 
> <mailto:mk.maddin at gmail.com>> wrote:
> 
>     Hi John,
> 
>     if you are using LDAP - why not permitting a LDAP group (which
>     already exists during install) and then configure sudo via LDAP?
> 
>     Thats how I solved it for my soho environment.
> 
>     See: https://www.sudo.ws/man/1.8.17/sudoers.ldap.man.html
> 
>     Kind Regards
> 
>     Martin
> 
>     On Wed, Jan 9, 2019, 22:06 John G Heim <jheim at math.wisc.edu
>     <mailto:jheim at math.wisc.edu> wrote:
> 
>         So I had this problem. I want to configure certain users to have
>         sudo on
>         the workstations I manage. Problem we do ldap authenticaition --
>         so the
>         users don't exist during the install. I can easily write an fai
>         script
>         to do an adduser but it doesn't work because the user doesn't exist
>         during the install. What I needed to do is to run a script once
>         after
>         the system reboots into the newly installed operating system. I
>         thought
>         about putting a script on there that would run at boot time and
>         delete
>         itself. But that's ugly and failure prone. But I came up with a
>         solution
>         that is much more reliable and flexible.
> 
>         1. Create a crontab file to be copied to the target system
>         during the
>         install. For example, during my fai installs, I create a class
>         called
>         INSTALL. So I created a crontab file
>         /srv/fai/config/files/etc/crontab/INSTALL.
> 
>         Put a command like this in this file:
> 
>         @reboot root fai --class/dev/null=POSTINST softupdate
> 
>         2. Add an fcopy command to one of your installation scripts to
>         copy the
>         crontab file:
> 
>         fcopy -Bi /etc/crontab
> 
>         3. Create another, normal crontab file without the above line
>         and call
>         it POSTINST or whatever you called the class in the first
>         crontab. In
>         this example, it would be
>         /srv/fai/config/files/etc/crontab/POSTINST.
> 
>         4. in your fai script space, create a directory called POSTINST
> 
>         mkdir /srv/fai/config/scripts/POSTINST
> 
>         5. Put a script in there to install the normal crontab file
> 
>         fcopy -Bi /etc/crontab
> 
>         6. Put scripts to do whatever else you want into that same
>         directory.
>         These scripts will be run just once when the system reboots
>         after the
>         original fai install. The target machine will look completely
>         normal and
>         there won't be any extra programs/scripts on it (unless you
>         count fai
>         itself).
> 
>         Verstehst du?
> 
>         -- 
>         --
>         John G. Heim; jheim at math.wisc.edu <mailto:jheim at math.wisc.edu>;
>         sip://jheim@sip.linphone.org <mailto:jheim at sip.linphone.org>
>