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| Current File : //compat/linux/proc/self/root/usr/share/examples/diskless/README.BOOTP |
IMPORTANT NOTE:
As of Feb. 11, 2002 (and indeed, for quite some time before that),
the /etc/rc.diskless{1,2} scripts support a slightly different
diskless boot process than the one documented in the rest of
this file (which is 3 years old).
I am not deleting the information below because it contains some
useful background information on diskless operation, but for the
actual details you should look at /etc/rc.diskless1, /etc/rc.diskless2,
and the /usr/share/examples/diskless/clone_root script which can
be useful to set up clients and server for diskless boot.
--- $FreeBSD: release/9.1.0/share/examples/diskless/README.BOOTP 130786 2004-06-20 13:17:37Z mpp $ ---
------------------------------------------------------------------------
BOOTP configuration mechanism
Matthew Dillon
dillon@backplane.com
BOOTP kernels automatically configure the machine's IP address, netmask,
optional NFS based swap, and NFS based root mount. The NFS server will
typically export a shared read-only /, /usr, and /var to any number of
workstations. The shared read-only root is typically either the server's
own root or, if you are more security conscious, a contrived root.
The key issue with starting up a BOOTP kernel is that you typically want
to export read-only NFS partitions from the server, yet still be able to
customize each workstation ( or not ).
/etc/rc.diskless1 is responsible for doing core mounts and for retargeting
/conf/ME ( part of the read-only root NFS mount ) to /conf/$IP_OF_CLIENT.
/etc/rc.conf.local and /etc/rc.local, along with other machine-specific
configuration files, are typically softlinks to /conf/ME/<filename>.
In the BOOTP workstation /conf/$IP/rc.conf.local, you must typically
turn *OFF* most of the system option defaults in /etc/rc.conf as well
as do additional custom configuration of your environment
The /usr/src/share/examples/diskless directory contains a typical
X session / sshd based workstation configuration. The directories
involved are HT.DISKLESS/ and 192.157.86.12/.
Essentially, the $IP/ directory ( which rc.diskless looks for in
/conf/$IP/ ) contains all the junk. The HT.DISKLESS directory exists
to hold common elements of your custom configuration so you do not have
to repeat those elements for each workstation. The example /conf
structure included here shows how to create a working sshd setup ( so
you can sshd into the diskless workstation ), retarget xdm's pid and error
files to R+W directories if /usr is mounted read-only, and retarget
syslogd and other programs. This example is not designed to run out of
the box and some modifications are required.
>> NOTE << HT.DISKLESS/ttys contains the typical configuration required
to bring X up at boot time. Essentially, it runs xdm in the foreground
with the appropriate arguments rather then a getty on ttyv0. You must
run xdm on ttyv0 in order to prevent xdm racing with getty on a virtual
terminal. Such a race can cause your keyboard to be directed away from
the X session, essentially making the session unusable.
Typically you should start with a clean slate by tar-copying this example
directory to /conf and then hack on it in /conf rather then in
/usr/share/examples/diskless.
BOOTP CLIENT SETUP
Here is a typical kernel configuration. If you have only one ethernet
interface you do not need to wire BOOTP to a specific interface name.
BOOTP requires NFS and NFS_ROOT, and our boot scripts require MFS. If
your /tmp is *not* a softlink to /var/tmp, the scripts also require NULLFS
# BootP
#
options BOOTP # Use BOOTP to obtain IP address/hostname
options BOOTP_NFSROOT # NFS mount root filesystem using BOOTP info
options "BOOTP_NFSV3" # Use NFS v3 to NFS mount rootoptions
options BOOTP_COMPAT # Workaround for broken bootp daemons.
#options "BOOTP_WIRED_TO=de0"
options MFS # Memory File System
options NFS # Network Filesystem
options NFS_ROOT # Nfs can be root
options NULLFS # nullfs to map /var/tmp to /tmp
BOOTP SERVER SETUP
The BOOTP server must be running on the same logical LAN as the the
BOOTP client(s). You need to setup two things:
(1) You need to NFS-export /, /usr, and /var.
(2) You need to run a BOOTP server. DHCPD can do this.
NFS Export:
Here is an example "/etc/exports" file.
/ -ro -maproot=root: -network 192.157.86.0 -mask 255.255.255.192
/usr -ro -maproot=root: -network 192.157.86.0 -mask 255.255.255.192
/var -ro -maproot=root: -network 192.157.86.0 -mask 255.255.255.192
In order to be an NFS server, the server must run portmap, mountd,
nfsd, and rpc.statd. The standard NFS server options in /etc/rc.conf
will work ( you should put your overrides in /etc/rc.conf.local on the
server and not edit the distribution /etc/rc.conf, though ).
BOOTP Server:
This configuration file "/etc/dhcpd.conf" example is for
the '/usr/ports/net/isc-dhcp' dhcpd port.
subnet 192.157.86.0 netmask 255.255.255.192 {
# range if you want to run the core dhcpd service of
# dynamic IP assignment, but it is not used with BOOTP
# workstations
range 192.157.86.32 192.157.86.62;
# misc configuration.
#
option routers 192.157.86.2;
option domain-name-servers 192.157.86.2;
server-name "apollo.fubar.com";
option subnet-mask 255.255.255.192;
option domain-name-servers 192.157.86.2;
option domain-name "fubar.com";
option broadcast-address 192.157.86.63;
option routers 192.157.86.2;
}
host test1 {
hardware ethernet 00:a0:c9:d3:38:25;
fixed-address 192.157.86.11;
option root-path "192.157.86.2:/";
option option-128 "192.157.86.2:/images/swap";
}
host test2 {
# hardware ethernet 00:e0:29:1d:16:09;
hardware ethernet 00:10:5a:a8:94:0e;
fixed-address 192.157.86.12;
option root-path "192.157.86.2:/";
option option-128 "192.157.86.2:/images/swap";
}
SWAP. This example includes options to automatically BOOTP configure
NFS swap on each workstation. In order to use this capabilities you
need to NFS-export a swap directory READ+WRITE to the workstations.
You must then create a swap directory for each workstation you wish to
assign swap to. In this example I created a dummy user 'lander' and
did an NFS export of /images/swap enforcing a UID of 'lander' for
all accesses.
apollo:/usr/ports/net# ls -la /images/swap
total 491786
drwxr-xr-x 2 root wheel 512 Dec 28 07:00 .
drwxr-xr-x 8 root wheel 512 Jan 20 10:54 ..
-rw-r--r-- 1 lander wheel 33554432 Dec 23 14:35 swap.192.157.86.11
-rw-r--r-- 1 lander wheel 335544320 Jan 24 16:55 swap.192.157.86.12
-rw-r--r-- 1 lander wheel 134217728 Jan 21 17:19 swap.192.157.86.6
A swap file is best created with dd:
# create a 32MB swap file for a BOOTP workstation
dd if=/dev/zero of=swap.IPADDRESS bs=1m count=32
It is generally a good idea to give your workstations some swap space,
but not a requirement if they have a lot of memory.