1# $FreeBSD: src/share/examples/diskless/README.BOOTP,v 1.2.4.1 2002/02/12 17:43:11 luigi Exp $ 2# Notes on diskless boot. 3 4IMPORTANT NOTE: 5 6For quite some time 7the /etc/rc.d/{initdiskless,diskless} scripts support a slightly different 8diskless boot process than the one documented in the rest of this file. 9 10I am not deleting the information below because it contains some 11useful background information on diskless operation, but for the 12actual details you should look at diskless(8), /etc/rc.d/initdiskless, 13/etc/rc.d/diskless, 14and the /usr/share/examples/diskless/clone_root script which can 15be useful to set up clients and server for diskless boot. 16 17----------------------------------------------------------------------- 18 19 BOOTP configuration mechanism 20 21 Matthew Dillon 22 dillon@backplane.com 23 24 BOOTP kernels automatically configure the machine's IP address, netmask, 25 optional NFS based swap, and NFS based root mount. The NFS server will 26 typically export a shared read-only /, /usr, and /var to any number of 27 workstations. The shared read-only root is typically either the server's 28 own root or, if you are more security conscious, a contrived root. 29 30 The key issue with starting up a BOOTP kernel is that you typically want 31 to export read-only NFS partitions from the server, yet still be able to 32 customize each workstation ( or not ). 33 34 /etc/rc.diskless1 is responsible for doing core mounts and for retargeting 35 /conf/ME ( part of the read-only root NFS mount ) to /conf/$IP_OF_CLIENT. 36 /etc/rc.conf.local and /etc/rc.local, along with other machine-specific 37 configuration files, are typically softlinks to /conf/ME/<filename>. 38 39 In the BOOTP workstation /conf/$IP/rc.conf.local, you must typically 40 turn *OFF* most of the system option defaults in /etc/rc.conf as well 41 as do additional custom configuration of your environment 42 43 The /usr/src/share/examples/diskless directory contains a typical 44 X session / sshd based workstation configuration. The directories 45 involved are HT.DISKLESS/ and 192.157.86.12/. 46 47 Essentially, the $IP/ directory ( which rc.diskless looks for in 48 /conf/$IP/ ) contains all the junk. The HT.DISKLESS directory exists 49 to hold common elements of your custom configuration so you do not have 50 to repeat those elements for each workstation. The example /conf 51 structure included here shows how to create a working sshd setup ( so 52 you can sshd into the diskless workstation ), retarget xdm's pid and error 53 files to R+W directories if /usr is mounted read-only, and retarget 54 syslogd and other programs. This example is not designed to run out of 55 the box and some modifications are required. 56 57 >> NOTE << HT.DISKLESS/ttys contains the typical configuration required 58 to bring X up at boot time. Essentially, it runs xdm in the foreground 59 with the appropriate arguments rather then a getty on ttyv0. You must 60 run xdm on ttyv0 in order to prevent xdm racing with getty on a virtual 61 terminal. Such a race can cause your keyboard to be directed away from 62 the X session, essentially making the session unusable. 63 64 Typically you should start with a clean slate by tar-copying this example 65 directory to /conf and then hack on it in /conf rather then in 66 /usr/share/examples/diskless. 67 68 BOOTP CLIENT SETUP 69 70 Here is a typical kernel configuration. If you have only one ethernet 71 interface you do not need to wire BOOTP to a specific interface name. 72 BOOTP requires NFS and NFS_ROOT, and our boot scripts require MFS. If 73 your /tmp is *not* a softlink to /var/tmp, the scripts also require NULLFS 74 75# BootP 76# 77options BOOTP # Use BOOTP to obtain IP address/hostname 78options BOOTP_NFSROOT # NFS mount root filesystem using BOOTP info 79options BOOTP_COMPAT # Workaround for broken bootp daemons. 80#options "BOOTP_WIRED_TO=de0" 81 82options MFS # Memory File System 83options NFS # Network Filesystem 84options NFS_ROOT # Nfs can be root 85options NULLFS # nullfs to map /var/tmp to /tmp 86 87 BOOTP SERVER SETUP 88 89 The BOOTP server must be running on the same logical LAN as the 90 BOOTP client(s). You need to setup two things: 91 92 (1) You need to NFS-export /, /usr, and /var. 93 94 (2) You need to run a BOOTP server. DHCPD can do this. 95 96 97 NFS Export: 98 99 Here is an example "/etc/exports" file. 100 101/ -ro -maproot=root: -network 192.157.86.0 -mask 255.255.255.192 102/usr -ro -maproot=root: -network 192.157.86.0 -mask 255.255.255.192 103/var -ro -maproot=root: -network 192.157.86.0 -mask 255.255.255.192 104 105 In order to be an NFS server, the server must run portmap, mountd, 106 nfsd, and rpc.statd. The standard NFS server options in /etc/rc.conf 107 will work ( you should put your overrides in /etc/rc.conf.local on the 108 server and not edit the distribution /etc/rc.conf, though ). 109 110 BOOTP Server: 111 112 This configuration file "/etc/dhcpd.conf" example is for 113 the '/usr/ports/net/isc-dhcp' dhcpd port. 114 115 subnet 192.157.86.0 netmask 255.255.255.192 { 116 # range if you want to run the core dhcpd service of 117 # dynamic IP assignment, but it is not used with BOOTP 118 # workstations 119 range 192.157.86.32 192.157.86.62; 120 121 # misc configuration. 122 # 123 option routers 192.157.86.2; 124 option domain-name-servers 192.157.86.2; 125 126 server-name "apollo.fubar.com"; 127 option subnet-mask 255.255.255.192; 128 option domain-name-servers 192.157.86.2; 129 option domain-name "fubar.com"; 130 option broadcast-address 192.157.86.63; 131 option routers 192.157.86.2; 132 } 133 134 host test1 { 135 hardware ethernet 00:a0:c9:d3:38:25; 136 fixed-address 192.157.86.11; 137 option root-path "192.157.86.2:/"; 138 option option-128 "192.157.86.2:/images/swap"; 139 } 140 141 host test2 { 142 # hardware ethernet 00:e0:29:1d:16:09; 143 hardware ethernet 00:10:5a:a8:94:0e; 144 fixed-address 192.157.86.12; 145 option root-path "192.157.86.2:/"; 146 option option-128 "192.157.86.2:/images/swap"; 147 } 148 149 SWAP. This example includes options to automatically BOOTP configure 150 NFS swap on each workstation. In order to use this capabilities you 151 need to NFS-export a swap directory READ+WRITE to the workstations. 152 153 You must then create a swap directory for each workstation you wish to 154 assign swap to. In this example I created a dummy user 'lander' and 155 did an NFS export of /images/swap enforcing a UID of 'lander' for 156 all accesses. 157 158 apollo:/usr/ports/net# ls -la /images/swap 159 total 491786 160 drwxr-xr-x 2 root wheel 512 Dec 28 07:00 . 161 drwxr-xr-x 8 root wheel 512 Jan 20 10:54 .. 162 -rw-r--r-- 1 lander wheel 33554432 Dec 23 14:35 swap.192.157.86.11 163 -rw-r--r-- 1 lander wheel 335544320 Jan 24 16:55 swap.192.157.86.12 164 -rw-r--r-- 1 lander wheel 134217728 Jan 21 17:19 swap.192.157.86.6 165 166 A swap file is best created with dd: 167 168 # create a 32MB swap file for a BOOTP workstation 169 dd if=/dev/zero of=swap.IPADDRESS bs=1m count=32 170 171 It is generally a good idea to give your workstations some swap space, 172 but not a requirement if they have a lot of memory. 173 174