Advice for hacking on ufs/ffs

[Dag-Erling Smørgrav]

Eric Anderson <anderson at centtech.com> writes:
> DES - anything special with the nfs root'ed box, to make this work
> well?

Not really.  Here's a short summary.  Assume you have a spare disk in
your workstation, ad1, which you are going to use for your test box.

Create and populate a file system for your test box:

% mkdir /box
% echo '/dev/ad1 /box ufs rw 2 2' >>/etc/fstab
% newfs -U /box
% mount /box
% mergemaster -i -D /box
% cd /usr/src
% make installworld DESTDIR=/box

Check out a source tree:

% cd /box/usr
% cvs -R -q -d /home/ncvs co -P src

Chroot into your sandbox:

% echo 'devfs /box/dev devfs rw 0 0' >>/etc/fstab
% mount /box/dev
% chroot /box /bin/sh

At this point you want to create an appropriate make.conf and kernel
config for your test box.

Useful make.conf settings include:

# build *everything* with debugging symbols
DEBUG_FLAGS ?= -g

# and leave them in when installing
STRIP = # empty

# don't clean out your previous build before rebuilding the kernel -
# you'll be doing that a lot
NO_KERNELCLEAN = YES

When you are ready, build and install world and kernel:

[still inside the chroot]
% cd /usr/src
% make buildworld buildkernel && make installworld installkernel

You don't really need to chroot; you can do everything outside the
sandbox, making sure that DESTDIR and __MAKE_CONF are correctly
defined.  I find it easier to work in a chroot because it saves me
from having to remember just that.

If you're going to use a serial console, kick up the speed a notch:

[still inside the chroot]
% cat >>/boot/loader.conf <<EOF
console="comconsole"
comconsole_speed="115200"
boot_verbose="YES"
EOF

You'll also need an fstab:

[still inside the chroot]
% cat >>/etc/fstab <<EOF
workstation:/box    /           nfs     rw          0 0
md                  /tmp        mfs     rw,-s8m     0 0
md                  /var/tmp    mfs     rw,-s8m     0 0
md                  /var/run    mfs     rw,-s8m     0 0
EOF

Now, outside the chroot, you need to set things up for PXE.  First,
you'll need to set up a DHCP server which will hand out an IP address
to your test box and instruct it to get the loader and root file
system from your workstation:

% pkg_add -r isc-dhcp3-server
% cat >/usr/local/etc/dhcp.conf <<EOF
ddns-update-style none;
authoritative;

default-lease-time 86400;
max-lease-time 604800;

subnet 10.0.0.0 netmask 255.255.255.0 {

        option routers 10.0.0.1;
        option subnet-mask 255.255.255.0;
        option broadcast-address 10.0.0.255;
        option domain-name "example.com";
        option domain-name-servers 10.0.0.1;

        host box {
                hardware ethernet 00:01:02:03:04:05;
                fixed-address box.example.com;
                next-server workstation.example.com;
                filename "pxeboot";
                option root-path "/box";
        }
}
EOF
% echo 'dhcp_enable="YES"' >>/etc/rc.conf
% /usr/local/etc/rc.d/isc-dhcpd.sh start

Of course, you also need to set up NFS and TFTP:

[nfs]
% echo 'nfs_server_enable="YES"' >>/etc/rc.conf
% echo 'mountd_enable="YES"' >>/etc/rc.conf
% echo '/box -maproot=root -network 10.0.0.0 -mask 255.255.255.0' >>/etc/exports
% /etc/rc.d/nfsserver start
% /etc/rc.d/mountd start

[tftp]
% mkdir /tftpboot
% cp /box/boot/pxeboot /tftpboot
% sed -i.bak -e 's/^#tftp/tftp/' /etc/inetd.conf
% echo 'inetd_enable="YES"' >>/etc/rc.conf
% /etc/rc.d/inetd start

At this point, if I didn't miss anything, you should be able to just
switch on your test box and watch it boot.

DES
-- 
Dag-Erling Smørgrav - des at des.no