[Ltsp-developer] Use of dhclient during boot process

[Skip G. <sg...@at...>]

Hi Folks,

About 6 months ago I started developing a PowerPC version of=20
the LTSP, which meant everything needed to be recompiled.=20
My clients are 40 MB, 66 Mhz PowerPCs, so I was interested=20
in anything I could do to keep the footprint down.

Early on, I discovered the RAMDISK wasn't being freed up in=20
rc.local. I discovered the reason was that the dhclient=20
process had the leases file open, so I wrote some code to=20
get the pid of the dhclient process and kill it. I could=20
then release memory allocated to the RAMDISK.

I then restarted the dhclient process, and that's where the=20
fun started: In restarting the dhclient process, I created=20
a memory leak, which rendered the systems unusable after=20
about 5-6 hours. Now that I understand what's causing the=20
memory leak, I'd like to propose that the clients do not=20
need to run dhclient after they have started the network.=20
The IP addresses are statically assigned, so they should=20
not need to be renewed. The network cannot be shutdown and=20
restarted without losing the root filesystem.

So, in rc.local, I propose we kill the dhclient process=20
before we try to free the RAMDISK. Sample code is attached:

**********************************************************************
echo "Setting up tmpfs on /tmp"
mount tmpfs /tmp -t shm -o size=3D1m,rw

#
# we need to kill dhclient before we can free the RAMDRIVE
#
PID=3D`ps -ae|grep dhclient|head -n 1 -|cut -c 1-5`
kill -9 $PID

# Here I create the directory structure on /tmp

# Free up the initrd
umount /oldroot
**********************************************************************

--Skip