Printcap for a large site; how???

[Bob Gregory]

In article <5067 at brazos.Rice.edu> pwa-b!m086414 (Fred Comins) writes:
>X-Sun-Spots-Digest: Volume 9, Issue 50, message 2
>
>We have many printers and are getting another 45 laser jets.  The problem
>is that all users want to be able to get to any of the printers.   I'm
>looking for advice on the easiest way to keep this managed.  Currently we
>were planning to use rdist with 1 master printcap with an entry for every
>printer.  Any better ideas?  Do I have to have a spool directory for each?

I tried to respond to the sender, but mail bounced, and meanwhile I've
seen no response posted.  Although the solution described here is not
especially Sun-specific, other Sun sites with central administration of a
number of similarly configured systems may find this useful.

We have ~40 printers on ~20 Suns (so far).  We also need to allow
promiscuous printing.  Deciding which printers need access from which
hosts is usually more trouble than it's worth.

We keep a "master" directory on a server which maintains all our
printcaps.  You do have to create separate spooling directories for each
printer, so this directory has a sub-directory which is a "master" copy of
(virgin) /{usr|var}/spool/lpd.  Bad owner/modes on the spooling directory
is a common mistake, so a script creates new directories there with the
right modes and ownership, and this is propagated by rdist(1) along with
the printcaps.  If the modes get munged later, rdist will gripe about the
mismatch.  This has cured chronic "broken" spoolers (and found a few
"fixed" with mode 777).

Our README from this directory:

This tree maintains /etc/printcap and the lpd(8) spooling directories
across the network.

printcaps for host machines of interest are the files [a-z]* in this
directory.  Scripts, Distfiles, or Subdirectories (e.g. Lpd) are by
convention MixedCase.

 corollary: echo [a-z]* shows machines which may be considered.
            (remove editor backups or expect grumbles).

to add a new host
   touch newhost
or if it has a meaningful printcap
   rcp newhost:/etc/printcap ./newhost

printcap files may have a host-specific part at the beginning followed by
the common part.  the host-specific part is required for the machine which
actually spools to the printer.  the common part makes printers known to
other hosts for remote spooling.

Adding a new printer needs a new entry in the printcap file of the host
which has the printer attached. The lpr(1), etc. ignore later duplicate
printcap entries, so the host-specific stuff is at the beginning of the
file.  Changes after the header of the Common file will be lost.   Entries
in Common should be created with the :rp: capability (keep all aliases the
same, please).

Common  - defines all printers as remote.  Alter this file
          when adding or removing printers, or changing aliases.

Edit    - integrate Common into all [ or a few ] printcap files.
          Usage: Edit [ host ... ]

Makedir - create new spooling directories under Lpd to be propagated
          with rdist(1) via Install
          Usage: Makedir newlpdir [ newlpdir ... ]

Install - propagate printcap and spooling directories to all
          [ or a few ] hosts.  (hosts up? try rup(1))
          Usage: Install [ host ... ]

 --------------- Install -------------
#!/bin/csh -f
cd /usr/rdist/printcap   # or wherever we are...

if $#argv > 1 then
   set hosts = ( $* )
else
   set hosts = ( [a-z]* )
endif

foreach host ( $hosts )
    rdist -f Distfile.install -d HOST=$host -d FILE=$cwd/$host ### 
end
rdist -f Distfile.lpd -d HOSTS="($hosts)"

 ------------- Edit -------------
#!/bin/csh -f
cd /usr/rdist/printcap   # or wherever we are...

if $#argv > 1 then
   set hosts = ( $* )
else
   set hosts = ( [a-z]* )
endif

foreach host ( $hosts )
    awk '/common printcap/ { exit } { print }' $host > /tmp/Edit.$$
    cat /tmp/Edit.$$ Common > $host
end
rm -f /tmp/Edit.$$

 ----- Common looks something like this -----

# common printcap  (don't mess with this line)
#
lp_mrf|mrf|Master Reference Files matrix:\
	:lp=:rm=orb:rp=mrf:sd=/usr/spool/lpd/mrf:lf=/usr/adm/lpderrs:
lp_lib|lib|Library Laser:\
	:lp=:rm=nova:rp=lib:sd=/usr/spool/lpd/lib:lf=/usr/adm/lpderrs:
...etc...

 ------------- Makedir ------------
#!/bin/csh -f
cd /usr/rdist/printcap/Lpd      # master spooling directory
foreach nudir ( $* )
 if ( -d $nudir ) then
   echo "$nudir already exists!"
 else
   mkdir $nudir
 endif
 chown daemon.daemon $nudir && chmod 770 $nudir
 ls -ldg $nudir
end

 ---------------- Distfiles called by Install ---------------
Distfile.install:

     ${FILE} -> ${HOST}
             install /etc/printcap ;  # optional -y , see note below

Distfile.lpd:

     /usr/rdist/printcap/Lpd -> ${HOSTS}
             install /usr/spool/lpd ;


NOTE: if local editing is permitted on the remotes, consider the -y flag
to rdist(1), and run Install both before and after editing.

Have also used the above technique for administering various other "local"
files, when there is enough in common, or interrelationship, to warrant
it.  We usually do /etc/fstab this way.  Changes to exported filesystems
are more frequent than local ones, and always affect several systems
(servers have clients).  Most of the /etc/passwd files are identical (we
use YP), and it's handy to change the root password everywhere at once.  I
believe this should scale well to larger networks with similar needs for
centralized maintenance.