Now it's time to prepare the server to serve diskless clients.
The first thing todo is build a kernel with the nescesarry stuff in to support root over nfs. Take the following steps to build your kernel:
mknod /dev/nfsroot b 0 255.
rdev <path-to-zImage>/zImage /dev/nfsroot
/etc/rc.d/rc.devfs save /etc/sysconfig
The next step is to create and populate /tftpboot
This is all handled by a big script since putting a long list of commands into this howto seemed pretty useless to me. If you want todo this manual just read the script and type it in as you go ;)
This setup script thus some nasty things like nuke /tmp, temporary kill syslog, umount /proc. So make sure that noone is using the machine during this, and that X isn't running. Just making sure your the only one logged in on a text-console is enough, no need to change runlevels.
DISCLAIMER: this script has been tested but nevertheless if it messes up your server your on your own. I can take no responsibility what so ever. Lett me repeat this howto is only for experienced linux sysadmins. Also this is script is designed to be run once and I really mean once. Running it twice will nuke: /etc/fstab, /etc/X11/XF86Config, /etc/X11/X and /etc/conf.modules.
Now with that said, just cut and paste the script make it executable, execute it and pray to the holy penguin that it works ;)
#!/bin/sh
SERVER_NAME=`hostname -s`
###
echo creating /etc/rc.d/rc.ws
#this basicly just echos the entire script ;)
echo "#root on nfs stuff
SERVER=$SERVER_NAME
#we need proc for mtab, route etc
mount -t proc /proc /proc
IP=\`ifconfig eth0|grep inet|cut --field 2 -d ':'|cut --field 1 -d ' '\`
#if the first mount fails we're probably the server, or atleast something is
#pretty wrong, so only do the other stuff if the first mount succeeds
mount \$SERVER:/tftpboot/\$IP/sysconfig /etc/sysconfig -o nolock &&
{
#other mounts
mount \$SERVER:/home /home -o nolock
mount \$SERVER:/ /\$SERVER -o ro,nolock
#/var
echo Creating /var ...
mke2fs -q -i 1024 /dev/ram1 1024
mount /dev/ram1 /var -o defaults,rw
cp -a /tftpboot/var /
#network stuff
. /etc/sysconfig/network
HOSTNAME=\`cat /etc/hosts|grep \$IP|cut --field 2\`
route add default gw \$GATEWAY
ifup lo
}
#restore devfs settings
/etc/rc.d/rc.devfs restore /etc/sysconfig
umount /proc" > /etc/rc.d/rc.ws
###
echo splitting runlevel 3 for the client and server
mv /etc/rc.d/rc3.d /etc/rc.d/rc3.server
cp -a /etc/rc.d/rc3.server /etc/rc.d/rc3.ws
rm /etc/rc.d/rc3.ws/*network
rm /etc/rc.d/rc3.ws/*nfs
rm /etc/rc.d/rc3.ws/*nfsfs
rm /etc/rc.d/rc3.ws/S99local
ln -s /etc/sysconfig/rc.local /etc/rc.d/rc3.ws/S99local
ln -s /etc/rc.d/rc3.server /etc/sysconfig/rc3.d
ln -s /etc/sysconfig/rc3.d /etc/rc.d/rc3.d
###
echo making tmp a link to /var/tmp
rm -fR /tmp
ln -s var/tmp /tmp
###
echo moving various files around and create symlinks for them
echo mtab
/etc/rc.d/init.d/syslog stop
umount /proc
touch /proc/mounts
mount /proc
/etc/rc.d/init.d/syslog start
rm /etc/mtab
ln -s /proc/mounts /etc/mtab
echo fstab
mv /etc/fstab /etc/sysconfig
ln -s sysconfig/fstab /etc/fstab
echo X-config files
mkdir /etc/sysconfig/X11
mv /etc/X11/X /etc/sysconfig/X11
ln -s ../sysconfig/X11/X /etc/X11/X
mv /etc/X11/XF86Config /etc/sysconfig/X11
ln -s ../sysconfig/X11/XF86Config /etc/X11/XF86Config
echo conf.modules
mv /etc/conf.modules /etc/sysconfig
ln -s sysconfig/conf.modules /etc/conf.modules
echo isapnp.conf
mv /etc/isapnp.conf /etc/sysconfig
ln -s sysconfig/isapnp.conf /etc/isapnp.conf
###
echo creating a template dir for the ws directories
echo /tftpboot/template
mkdir /home/tftpboot
ln -s home/tftpboot /tftpboot
mkdir /tftpboot/template
mkdir /$SERVER_NAME
echo root
ln -s / /tftpboot/template/root
echo sysconfig
cp -a /etc/sysconfig /tftpboot/template/sysconfig
rm -fR /tftpboot/template/sysconfig/network-scripts
ln -s /$SERVER_NAME/etc/sysconfig/network-scripts \
/tftpboot/template/sysconfig/network-scripts
echo NETWORKING=yes > /tftpboot/template/sysconfig/network
echo `grep "GATEWAY=" /etc/sysconfig/network` >> /tftpboot/template/sysconfig/network
echo "/dev/nfsroot / nfs defaults 1 1" > /tftpboot/template/sysconfig/fstab
echo "none /proc proc defaults 0 0" >> /tftpboot/template/sysconfig/fstab
echo "#!/bin/sh" > /tftpboot/template/sysconfig/rc.local
chmod 755 /tftpboot/template/sysconfig/rc.local
rm /tftpboot/template/sysconfig/rc3.d
ln -s /etc/rc.d/rc3.ws /tftpboot/template/sysconfig/rc3.d
rm /tftpboot/template/sysconfig/isapnp.conf
echo var
cp -a /var /tftpboot/var
rm -fR /tftpboot/var/lib
ln -s /$SERVER_NAME/var/lib /tftpboot/var/lib
rm -fR /tftpboot/var/catman
ln -s /$SERVER_NAME/var/catman /tftpboot/var/catman
rm -fR /tftpboot/var/log/httpd
rm -f /tftpboot/var/log/samba/*
for i in `find /tftpboot/var/log -type f`; do cat /dev/null > $i; done
rm `find /tftpboot/var/lock -type f`
rm `find /tftpboot/var/run -type f`
echo /sbin/fsck.nfs
echo "#!/bin/sh
exit 0" > /sbin/fsck.nfs
chmod 755 /sbin/fsck.nfs
echo all done
Now we need to make a few manual adjustments to the server:
#for root over nfs workstations. /etc/rc.d/rc.ws
The server must ofcourse export the appropriate filesystems and asign the ip addresses to the clients.
We need to export some dir's for the workstations so for the situation here at the university I would add the following to /etc/exports:
/ *.st.hhs.nl(ro,no_root_squash) /home *.st.hhs.nl(rw,no_root_squash)
Ofcourse use the apropriate domain ;) and restart nfs by typing:
/etc/rc.d/init.d/nfs restart
Note for knfsd users: knfsd doesn't allow you to have multiple exports on one partition with different permissions. Also knfsd doesn't allow clients to go past partition boundaries for example if a client mounts / and /usr is a different partition it won't have access to /usr. Thus if you use knfsd, at least /home should be on a different partition, the server prepare script already puts /tftpboot in /home so that doesn't need a seperate partition. If you've got any other partitions your clients should have access to export them seperatly and add mount commands for them to /etc/rc.d/rc.ws.
/etc/rc.d/init.d/inetd restart