Re: How to detect the number of network adapters installed from kickstart file for network config?

On Sat, Feb 19, 2011 at 04:09, Patrick Lists <[email protected]> wrote:
> You could test for the number of interfaces. Since I'm a total n00b in this
> area hopefully the experienced folks who monitor this list will have a good
> laugh at my "scripting" and come up with something better that actually
> works :)
>
> Here's how I would try to solve it. Totally untested, use at own risk. Mind
> the linewrap. It's all one line. My box has lo, br0, eth0 and virbr0 so the
> script should give a total of 4 interfaces.
>
> $ ifconfig -a | grep -vE 'inet|UP|RX|TX|collisions|Interrupt' | awk 'BEGIN
> {no_of_interfaces=0} /^[a-z]/ {print $1}' | awk 'END {no_of_interfaces=NR;
> print "Number of interfaces: " no_of_interfaces}'
>
> Number of interfaces: 4 (correct so apparently this works)
>
> You could add this to the %pre section in your kickstart file:
>
> %pre
> NO_OF_INTERFACES=`ifconfig -a | grep -vE
> 'inet|UP|RX|TX|collisions|Interrupt' | awk 'BEGIN {no_of_interfaces=0}
> /^[a-z]/ {print $1}' | awk 'END {no_of_interfaces=NR; print
> no_of_interfaces}'`
> echo "INTERFACE_COUNT=$NO_OF_INTERFACES" > /tmp/interface_count.txt
>
> Then in the %post section test if the value is greater than or equal to 2 in
> which case you configure both interfaces. Or else configure one interface:
>
> %post
> # first get the nr of interfaces from the interface_count.txt file
> # afaik usually at the top of %post
> source /tmp/interface_count.txt
>
> # test the value. not sure if I need to quote INTERFACES and 2
> if [ "\$INTERFACE_COUNT" -ge "2" ]; then
>  # configure 2 nics
>  network --device eth0 --bootproto dhcp
>  network --device eth1 --onboot no --bootproto dhcp
> else
>  # configure 1 nic
>  network --device eth0 --bootproto dhcp
> fi
>
> Since I don't know awk I got the syntax from the excellent n00b-friendly awk
> tutorial at
> http://bashshell.net/stream-filtering-utilities/exercise-1-learning-awk-basics/
>
> Hope this helps.
>
> Regards,
> Patrick

Nice Idea Patrick,

It just a but, it will include WLAN, Local loopback as well and not
only ethX interfaces.

So just change the grep to:
ifconfig -a | grep -E 'eth' | awk 'BEGIN {no_of_interfaces=0} /^[a-z]/
{print $1}' | awk 'END {no_of_interfaces=NR; print "Number of
interfaces: " no_of_interfaces}'

will just count the eth interfaces.


Kind regards
Mats