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1.1 ! root 1: % $Id: examples.tex,v 5.2 90/06/23 22:21:57 jsp Rel $ ! 2: % ! 3: % Copyright (c) 1989 Jan-Simon Pendry ! 4: % Copyright (c) 1989 Imperial College of Science, Technology & Medicine ! 5: % Copyright (c) 1989 The Regents of the University of California. ! 6: % All rights reserved. ! 7: % ! 8: % This code is derived from software contributed to Berkeley by ! 9: % Jan-Simon Pendry at Imperial College, London. ! 10: % ! 11: % Redistribution and use in source and binary forms are permitted provided ! 12: % that: (1) source distributions retain this entire copyright notice and ! 13: % comment, and (2) distributions including binaries display the following ! 14: % acknowledgement: ``This product includes software developed by the ! 15: % University of California, Berkeley and its contributors'' in the ! 16: % documentation or other materials provided with the distribution and in ! 17: % all advertising materials mentioning features or use of this software. ! 18: % Neither the name of the University nor the names of its contributors may ! 19: % be used to endorse or promote products derived from this software without ! 20: % specific prior written permission. ! 21: % THIS SOFTWARE IS PROVIDED ``AS IS'' AND WITHOUT ANY EXPRESS OR IMPLIED ! 22: % WARRANTIES, INCLUDING, WITHOUT LIMITATION, THE IMPLIED WARRANTIES OF ! 23: % MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE. ! 24: % ! 25: % @(#)examples.tex 5.1 (Berkeley) 7/19/90 ! 26: ! 27: ! 28: \Chapter{Examples} ! 29: ! 30: \Section{Starting \Amd} ! 31: \Amd\ is best started from {\tt /etc/rc.local}: ! 32: \begin{verbatim} ! 33: if [ -f /usr/local/etc/amd.start ]; then ! 34: sh /usr/local/etc/amd.start; (echo -n ' amd') >/dev/console ! 35: fi ! 36: \end{verbatim} ! 37: The shell script, {\tt amd.start}, contains: ! 38: \begin{verbatim} ! 39: PATH=/usr/local/etc:/bin:/usr/bin:/usr/ucb:$PATH export PATH ! 40: ! 41: # ! 42: # Either name of logfile or "syslog" ! 43: # ! 44: LOGFILE=syslog ! 45: #LOGFILE=/var/adm/am.log ! 46: ! 47: # ! 48: # Figure out whether domain name is in host name ! 49: # If the hostname is just the machine name then ! 50: # pass in the name of the local domain so that the ! 51: # hostnames in the map are domain stripped correctly. ! 52: # ! 53: case `hostname` in ! 54: *.*) dmn= ;; ! 55: *) dmn='-d doc.ic.ac.uk' ! 56: esac ! 57: ! 58: # ! 59: # Zap earlier log file ! 60: # ! 61: case "$LOGFILE" in ! 62: */*) ! 63: mv "$LOGFILE" "$LOGFILE"- ! 64: > "$LOGFILE" ! 65: ;; ! 66: syslog) ! 67: : nothing ! 68: ;; ! 69: esac ! 70: ! 71: cd /usr/local/etc ! 72: # ! 73: # -r restart ! 74: # -d dmn local domain ! 75: # -w wait wait between unmount attempts ! 76: # -l log logfile or "syslog" ! 77: # ! 78: eval ./amd -r $dmn -w 240 -l "$LOGFILE" \ ! 79: /homes amd.homes -cache:=inc \ ! 80: /home amd.home -cache:=inc \ ! 81: /vol amd.vol -cache:=inc \ ! 82: /n amd.net -cache:=inc ! 83: \end{verbatim} ! 84: ! 85: If the list of automount points and maps is contained in a file or YP map ! 86: it is easily incorporated onto the command line: ! 87: \begin{verbatim} ! 88: ... ! 89: eval ./amd -r $dmn -w 240 -l "$LOGFILE" `ypcat -k auto.master` ! 90: \end{verbatim} ! 91: ! 92: \Section{User Filesystems} ! 93: With more than one fileserver, the directories most frequently ! 94: cross-mounted are those containing user home directories. ! 95: A common convention used at Imperial College is to mount ! 96: the user disks under {\tt /home/}{\em machine}. ! 97: Typically, the {\tt /etc/fstab} file\footnote{{\tt /etc/checklist} ! 98: on System V} contained a long list of entries ! 99: such as: ! 100: \begin{quote} ! 101: {\em machine}{\tt :/home/}{\em machine}\ \ \tt /home/{\em machine}\ nfs \ldots ! 102: \end{quote} ! 103: for each fileserver on the network. ! 104: ! 105: There are numerous problems with this system. ! 106: The mount list can become quite large and some of the machines ! 107: may be down when a system is booted. ! 108: When a new fileserver is installed, {\tt /etc/fstab} must be ! 109: updated on every machine, the mount directory created and ! 110: the filesystem mounted. ! 111: In research environments most ! 112: people use the same few workstations, but it is convenient to go ! 113: to a colleague's machine and access your own files. ! 114: When a server goes down, it can cause a process on a client machine to ! 115: hang. By minimising the mounted filesystems to only include those ! 116: actively being used, there is less chance that a filesystem will be mounted ! 117: when a server goes down. ! 118: ! 119: The following is a short extract from a map taken from a research fileserver ! 120: at Imperial College. ! 121: Note the entry for {\tt localhost} which is used for users such as ! 122: the operator ({\tt opr}) who have a home directory on most machine as ! 123: {\tt /home/localhost/opr}. ! 124: \begin{verbatim} ! 125: /defaults opts:=rw,intr,grpid,nosuid ! 126: charm host!=${key};type:=nfs;rhost:=${key};rfs:=/home/${key} \ ! 127: host==${key};type:=ufs;dev:=/dev/xd0g ! 128: # ! 129: ... ! 130: ! 131: # ! 132: localhost type:=link;fs:=${host} ! 133: ... ! 134: # ! 135: # dylan has two user disks so have a ! 136: # top directory in which to mount them. ! 137: # ! 138: dylan type:=auto;fs:=${map};pref:=${key}/ ! 139: # ! 140: dylan/dk2 host!=dylan;type:=nfs;rhost:=dylan;rfs:=/home/${key} \ ! 141: host==dylan;type:=ufs;dev:=/dev/dsk/2s0 ! 142: # ! 143: dylan/dk5 host!=dylan;type:=nfs;rhost:=dylan;rfs:=/home/${key} \ ! 144: host==dylan;type:=ufs;dev:=/dev/dsk/5s0 ! 145: ... ! 146: # ! 147: toytown host!=${key};type:=nfs;rhost:=${key};rfs:=/home/${key} \ ! 148: host==${key};type:=ufs;dev:=/dev/xy1g ! 149: ... ! 150: # ! 151: zebedee host!=${key};type:=nfs;rhost:=${key};rfs:=/home/${key} \ ! 152: host==${key};type:=ufs;dev:=/dev/dsk/1s0 ! 153: # ! 154: # Just for access... ! 155: # ! 156: gould type:=auto;fs:=${map};pref:=${key}/ ! 157: gould/staff host!=gould;type:=nfs;rhost:=gould;rfs:=/home/${key} ! 158: # ! 159: gummo host!=${key};type:=nfs;rhost:=${key};rfs:=/home/${key} ! 160: ... ! 161: \end{verbatim} ! 162: ! 163: This map is shared by most of the machines listed so on those ! 164: systems any of the user disks is accessible via a consistent name. ! 165: \Amd\ is started with the following command ! 166: \begin{quote} ! 167: \tt amd /home amd.home ! 168: \end{quote} ! 169: ! 170: Note that when mounting a remote filesystem, the {\em automounted} ! 171: mount point is referenced, so that the filesystem will be mounted if ! 172: it is not yet (at the time the remote mountd obtains the file handle). ! 173: ! 174: \Section{Home Directories} ! 175: One convention for home directories is to locate them in {\tt /homes} so ! 176: user {\tt jsp}'s home directory is {\tt /homes/jsp}. ! 177: With more than a single fileserver it is convenient ! 178: to spread user files across several machines. ! 179: All that is required is a mount-map ! 180: which converts login names to an automounted directory. ! 181: ! 182: Such a map might be started by the command: ! 183: \begin{quote} ! 184: \tt amd /homes amd.homes ! 185: \end{quote} ! 186: where the map {\tt amd.homes} contained the entries: ! 187: \begin{quote}\raggedright ! 188: \tt ! 189: /defaults\ \ \ type:=link\ \ \ \# All the entries are of type:=link \\ ! 190: jsp\ \ \ \ \ \ \ \ \ fs:=/home/charm/jsp\\ ! 191: njw\ \ \ \ \ \ \ \ \ fs:=/home/dylan/dk5/njw\\ ! 192: ...\\ ! 193: phjk\ \ \ \ \ \ \ \ fs:=/home/toytown/ai/phjk\\ ! 194: sjv\ \ \ \ \ \ \ \ \ fs:=/home/ganymede/sjv ! 195: \end{quote} ! 196: Whenever a login name is accessed in {\tt /homes} a symbolic link ! 197: appears pointing to the real location of that user's home directory. ! 198: In this example, {\tt /homes/jsp} would appear to be a symbolic link ! 199: pointing to {\tt /home/charm/jsp}. ! 200: Of course, {\tt /home} would also be an automount point. ! 201: ! 202: This system causes an extra level of symbolic links to be used. ! 203: Although that turns out to be relatively inexpensive, an alternative is ! 204: to directly mount the required filesystems in the {\tt /homes} ! 205: map. The required map is simple, but long, and its creation best automated. ! 206: The entry for {\tt jsp} could be: ! 207: {\tt\begin{tabbing} ! 208: jsp\ \ \ \ \ \ \= -sublink:=\$\{key\};rfs:=/home/charm {\verb+\+}\kill \\ ! 209: jsp \> -sublink:=\$\{key\};rfs:=/home/charm {\verb+\+}\\ ! 210: \> host==charm;type:=ufs;dev:=/dev/xd0g {\verb+\+}\\ ! 211: \> host!=charm;type:=nfs;rhost:=charm ! 212: \end{tabbing}} ! 213: ! 214: This map can become quite big if it contains a large number of ! 215: entries. By combining two other features of \amd\ it can be greatly ! 216: simplified. First the \UFS\ partitions should be mounted under the ! 217: control of {\tt /etc/fstab}, taking care that they are mounted in the ! 218: same place that \amd\ would have automounted them, {\ie\ {\tt /a/{\em host}/home/{\em host}}}. ! 219: In this case {\tt /etc/fstab} on host {\tt charm} would have a line ! 220: \begin{verbatim} ! 221: /dev/xy0g /a/charm/home/charm 4.2 rw,nosuid,grpid 1 5 ! 222: \end{verbatim} ! 223: The map can then be changed to: ! 224: \begin{quote}\raggedright ! 225: \tt ! 226: /defaults\ \ \ \ type:=nfs;sublink:=\Var{key};opts:=rw,intr,nosuid,grpid\\ ! 227: jsp\ \ \ \ \ \ \ \ \ \ rhost:=charm;rfs:=/home/charm\\ ! 228: njw\ \ \ \ \ \ \ \ \ \ rhost:=dylan;rfs:=/home/dylan/dk5\\ ! 229: ...\\ ! 230: phjk\ \ \ \ \ \ \ \ \ rhost:=toytown;rfs:=/home/toytown;sublink:=ai/\Var{key}\\ ! 231: sjv\ \ \ \ \ \ \ \ \ \ rhost:=ganymede;rfs:=/home/ganymede ! 232: \end{quote} ! 233: ! 234: This map operates as usual on a remote machine (ie \Var{host} $\not=$ \Var{rhost}). ! 235: On the machine where the filesystem is stored (ie \Var{host} $=$ \Var{rhost}), ! 236: \amd\ will construct a local filesystem mount point which corresponds to ! 237: the name of the locally mounted \UFS\ partition. If \amd\ is started ! 238: with the ``-r'' option then instead of attempting an \NFS\ mount, \amd\ will ! 239: simply inherit the \UFS\ mount (\see \Ref{ifs}). ! 240: ! 241: %\Section{System Filesystem} ! 242: ! 243: \Section{Architecture Sharing} ! 244: %At the moment some of the research machines have sets of software ! 245: %mounted in {\tt /vol}. This contains subdirectories for \TeX, ! 246: %system sources, local sources, prolog libraries and so on. ! 247: Often a filesystem will be shared by machines of different architectures. ! 248: Separate trees can be maintained for the executable images for each ! 249: architecture, but it may be more convenient to have a shared tree, ! 250: with distinct subdirectories. ! 251: ! 252: A shared tree might have the following structure on the fileserver (called ! 253: {\tt fserver} in the example): ! 254: \begin{quote}\raggedright ! 255: \tt ! 256: local/tex \\ ! 257: local/tex/fonts \\ ! 258: local/tex/lib \\ ! 259: local/tex/bin \\ ! 260: local/tex/bin/sun3 \\ ! 261: local/tex/bin/sun4 \\ ! 262: local/tex/bin/hp9000 \\ ! 263: ... ! 264: \end{quote} ! 265: In this example, the subdirectories of {\tt local/tex/bin} should be ! 266: hidden when accessed via the automount point (conventionally {\tt /vol}). ! 267: A mount-map for {\tt /vol} to achieve this would look like: ! 268: {\tt\begin{tabbing} ! 269: tex/fonts\ \ \ \ \ \= \kill \\ ! 270: /defaults \> rfs:=/vol;sublink:=\$\{key\};rhost:=fserver;type:=link\\ ! 271: tex \> type:=auto;fs:=\$\{map\};pref:=\$\{key\}/\\ ! 272: tex/fonts \> host!=fserver;type:=nfs\ {\verb+\+}\\ ! 273: \> host==fserver;fs:=/usr/local \\ ! 274: tex/lib \> host!=fserver;type:=nfs\ {\verb+\+}\\ ! 275: \> host==fserver;fs:=/usr/local \\ ! 276: tex/bin \> -sublink:=\$\{key\}/\$\{arch\} host!=fserver;type:=nfs\ {\verb+\+}\\ ! 277: \> host:=fserver;fs:=/usr/local ! 278: \end{tabbing}} ! 279: When {\tt /vol/tex/bin} is referenced, the current machine architecture ! 280: is automatically appended to the path by the \Var{sublink} variable. ! 281: This means that users can have {\tt /vol/tex/bin} in their {\tt PATH} ! 282: without concern for architecture dependencies. ! 283: ! 284: \Section{Wildcard names \& Replicated Servers} ! 285: By using the wildcard facility, \amd\ can {\em overlay} an existing ! 286: directory with additional entries. ! 287: The system files are usually mounted under {\tt /usr}. If instead ! 288: \amd\ is mounted on {\tt /usr}, additional ! 289: names can be overlayed to augment or replace names in the ``master'' {\tt /usr}. ! 290: A map to do this would have the form: ! 291: {\tt\begin{tabbing} ! 292: local\ \ \ \ \ \= blah \kill \\ ! 293: local \> type:=auto;fs:=local-map\\ ! 294: share \> type:=auto;fs:=share-map\\ ! 295: {}* \> -type:=nfs;rfs:=/export/exec/\$\{arch\};sublink:="\$\{key\}"\ \verb+\+\\ ! 296: \> \ \ \ \ rhost:=fserv1\ \ rhost:=fserv2\ \ rhost:=fserv3 \\ ! 297: \end{tabbing}} ! 298: Note that the assignment to \Var{sublink} is surrounded by double quotes to ! 299: prevent the incoming key from causing the map to be misinterpreted. ! 300: This map has the effect of directing any access to {\tt /usr/local} or {\tt /usr/share} ! 301: to another automount point. ! 302: In this example, it is assumed that the {\tt /usr} files are replicated on ! 303: three fileservers: {\tt fserv1}, {\tt fserv2} and {\tt fserv3}. ! 304: For any references other than to {\tt local} ! 305: and {\tt share} one of the servers is used and a symbolic link to ! 306: {\tt \Var{autodir}/\Var{rhost}/export/exec/\Var{arch}/}{\em whatever} ! 307: is returned once an appropriate filesystem has been mounted. ! 308: ! 309: \Section{{\tt rwho} servers\label{example:rwho}} ! 310: ! 311: The {\tt /usr/spool/rwho} directory is a good candidate for automounting. ! 312: For efficiency reasons it is best to capture the rwho data on a small ! 313: number of machines and then mount that information onto a large number ! 314: of clients. The data written into the rwho files is byte order dependent ! 315: so only servers with the correct byte ordering can be used by a client: ! 316: {\tt\begin{tabbing} ! 317: usr/spool/rwho\ \ \ \ \ \= blah \kill \\ ! 318: /defaults \> type:=nfs \\ ! 319: usr/spool/rwho \> -byte==little;rfs:=/usr/spool/rwho \verb+\+\\ ! 320: \>\ \ \ \ rhost:=vaxA\ \ rhost:=vaxB \verb+\+\\ ! 321: \>|| -rfs:=/usr/spool/rwho \verb+\+\\ ! 322: \>\ \ \ \ rhost:=sun4\ \ rhost:=hp300\\ ! 323: \end{tabbing}} ! 324: ! 325: \Section{{\tt /vol}} ! 326: {\tt /vol} is used as a catch-all for volumes which do not have other conventional names. ! 327: ! 328: Below is part of the {\tt /vol} map for the domain {\tt doc.ic.ac.uk}. ! 329: The {\tt r+d} tree is used for new or experimental software that needs to be ! 330: available everywhere without installing it on all the fileservers. Users wishing to ! 331: try out the new software then simply include {\tt /vol/r+d/{bin,ucb}} in their path. ! 332: ! 333: The main tree resides on one host {\tt gould.doc.ic.ac.uk}, which has different ! 334: {\tt bin}, {\tt etc}, {\tt lib} and {\tt ucb} sub-directories for each machine ! 335: architecture. For example, {\tt /vol/r+d/bin} for a Sun-4 would be stored in ! 336: the sub-directory {\tt bin/sun4} of the filesystem {\tt /usr/r+d}. When it was ! 337: accessed a symbolic link pointing to {\tt /a/gould/usr/r+d/bin/sun4} would be ! 338: returned. ! 339: ! 340: \begin{verbatim} ! 341: /defaults type:=nfs;opts:=rw,grpid,nosuid,intr,soft ! 342: wp -opts:=rw,grpid,nosuid;rhost:=charm \ ! 343: host==charm;type:=link;fs:=/usr/local/wp \ ! 344: host!=charm;type:=nfs;rfs:=/vol/wp ! 345: ... ! 346: # ! 347: src -opts:=rw,grpid,nosuid;rhost:=charm \ ! 348: host==charm;type:=link;fs:=/usr/src \ ! 349: host!=charm;type:=nfs;rfs:=/vol/src ! 350: # ! 351: r+d type:=auto;fs:=${map};pref:=r+d/ ! 352: # per architecture bin,etc,lib&ucb... ! 353: r+d/bin rhost:=gould.doc.ic.ac.uk;rfs:=/usr/r+d;sublink:=${/key}/${arch} ! 354: r+d/etc rhost:=gould.doc.ic.ac.uk;rfs:=/usr/r+d;sublink:=${/key}/${arch} ! 355: r+d/include rhost:=gould.doc.ic.ac.uk;rfs:=/usr/r+d;sublink:=${/key} ! 356: r+d/lib rhost:=gould.doc.ic.ac.uk;rfs:=/usr/r+d;sublink:=${/key}/${arch} ! 357: r+d/man rhost:=gould.doc.ic.ac.uk;rfs:=/usr/r+d;sublink:=${/key} ! 358: r+d/src rhost:=gould.doc.ic.ac.uk;rfs:=/usr/r+d;sublink:=${/key} ! 359: r+d/ucb rhost:=gould.doc.ic.ac.uk;rfs:=/usr/r+d;sublink:=${/key}/${arch} ! 360: # hades pictures ! 361: pictures -opts:=rw,grpid,nosuid;rhost:=thpfs \ ! 362: host==thpfs;type:=link;fs:=/nbsd/pictures \ ! 363: host!=thpfs;type:=nfs;rfs:=/nbsd;sublink:=pictures ! 364: # hades tools ! 365: hades -opts:=rw,grpid,nosuid;rhost:=thpfs \ ! 366: host==thpfs;type:=link;fs:=/nbsd/hades \ ! 367: host!=thpfs;type:=nfs;rfs:=/nbsd;sublink:=hades ! 368: # bsd tools for hp. ! 369: bsd -opts:=rw,grpid,nosuid;arch==hp9000;rhost:=thpfs \ ! 370: host==thpfs;type:=link;fs:=/nbsd/bsd \ ! 371: host!=thpfs;type:=nfs;rfs:=/nbsd;sublink:=bsd ! 372: \end{verbatim} ! 373:
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