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:
Since we'll be using redhat-5.2 with kernel-2.2 you should asure yourself
that your redhat-5.2 is kernel-2.2 ready. RedHat has got an excellent howto
I use the same kernel for both server and ws, to avoid module conflicts
since they share the same /lib/modules. If this is not possible in your situation,
fake different kernel versions by editing the version number in the kernel's
top makefile. These different versionsnumbers will avoid any conflicts.
Besides the usual stuff the kernel should have the following:
ext2 compiled in (if used on server, or for both)
nfs and root-over-nfs compiled in (if used on client or both), to get the
nfs over root option in 2.2 enable ip-autoconfig in the network options. We'll
use bootp as configuration method.
ws networkcard support compiled in (if used on client or both)
compile devfs in (required for client, also nice for server)
anything else you normally use, modules for all other devices used on either
the server or all / some ws etc.
The kernel-src needs to be edited to make the default root-over-nfs mount:
/tftpboot/<ip>/root instead of just /tftpboot/<ip>. This is to
get a clean tree in /tftpboot with one dir per ws containing both the root
for it (a link to the actual server root) and any ws specific dirs.
For 2.0 This is a define in: "include/linux/nfs_fs.h" called
For 2.2 This is a define in: "fs/nfs/nfsroot.c"
Now just compile the kernel as usual, see the kernel-howto.
If you don't have /dev/nfsroot yet, create it by typing:
mknod /dev/nfsroot b 0 255.
After compiling the kernel set the root to nfsroot by typing:
rdev <path-to-zImage>/zImage /dev/nfsroot
Before booting with devfs you need to make a few changes to /etc/conf.modules,
append the contents of the conf.modules in the devfs documentation to it.
Since this new kernel is compiled for autoconfig of ip's it will try to
autoconf the ip of the server during bootup. Which ofcourse will fail since
it gives out the ip's. To avoid a long timeout add: append="ip=off"
To the linux section of /etc/lilo.conf.
Run lilo and boot the new kernel.
Due to devfs you'll have lost all symlinks on the server. With redhat this
is usually /dev/mouse and /dev/cdrom. Recreate these. If you also used to use
special ownerships, chown to appropiate files in /dev. Now save the /dev settings
(in /etc/sysconfig, since they might be ws specific):
Copy rc.devfs from the devfs documentation in the kernel source to /etc/rc.d/rc.devfs
and make it executable
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 ;)
echo creating /etc/rc.d/rc.ws
#this basicly just echos the entire script ;)
echo "#root on nfs stuff
#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 &&
mount \$SERVER:/home /home -o nolock
mount \$SERVER:/ /\$SERVER -o ro,nolock
echo Creating /var ...
mke2fs -q -i 1024 /dev/ram1 1024
mount /dev/ram1 /var -o defaults,rw
cp -a /tftpboot/var /
HOSTNAME=\`cat /etc/hosts|grep \$IP|cut --field 2\`
route add default gw \$GATEWAY
#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
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
ln -s /proc/mounts /etc/mtab
mv /etc/fstab /etc/sysconfig
ln -s sysconfig/fstab /etc/fstab
echo X-config files
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
mv /etc/conf.modules /etc/sysconfig
ln -s sysconfig/conf.modules /etc/conf.modules
mv /etc/isapnp.conf /etc/sysconfig
ln -s sysconfig/isapnp.conf /etc/isapnp.conf
echo creating a template dir for the ws directories
ln -s home/tftpboot /tftpboot
ln -s / /tftpboot/template/root
cp -a /etc/sysconfig /tftpboot/template/sysconfig
rm -fR /tftpboot/template/sysconfig/network-scripts
ln -s /$SERVER_NAME/etc/sysconfig/network-scripts \
echo NETWORKING=yes > /tftpboot/template/sysconfig/network
echo `grep "GATEWAY=" /etc/sysconfig/network` >> /tftpboot/template/sysconfig/network
echo "/dev/nfsroot / nfs defaults 1 1" > /tftpboot/template/sysconfig/fstab
echo "none /proc proc defaults 0 0" >> /tftpboot/template/sysconfig/fstab
echo "#!/bin/sh" > /tftpboot/template/sysconfig/rc.local
chmod 755 /tftpboot/template/sysconfig/rc.local
ln -s /etc/rc.d/rc3.ws /tftpboot/template/sysconfig/rc3.d
cp -a /var /tftpboot/var
rm -fR /tftpboot/var/lib
ln -s /$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`
exit 0" > /sbin/fsck.nfs
chmod 755 /sbin/fsck.nfs
echo all done
Manual adjustments to some files
Now we need to make a few manual adjustments to the server:
The ws setup script has to be sourced at the very beginning of rc.sysinit,
so add the following lines directly after setting the PATH:
#for root over nfs workstations.
Strip /etc/rc.d/rc3.ws to a bare minimum. It might be useful to create
something like rc.local.ws but I'll leave that up to you. Network and nfsfs
are already setup.The following have been already removed / updated by the
Ofcourse use the apropriate domain ;) and restart nfs by typing:
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.
Setting up bootp
If bootp isn't installed yet install it. It comes with RedHat.
Edit /etc/inetd.conf and uncomment the line beginning with bootps, if you
want to use a bootprom uncomment tftp while your at it.