designing /usr/local/{bin,etc,lib}

[Arnold de Leon]

Here is an update on what I've found/thought on a design for
managing /usr/local.

I was referred to the a paper presented at the Usenix LISA IV,
"The Depot".  IT is apparently available for anonymous ftp
at durer.cme.nist.gov (129.6.32.4) as ~ftp/pub/depot.lisa.ps.Z
I happen to have the LISA IV proceedings so did not end up
ftping a copy.

"The depot" is very close to what I want to do.  I am
working on adapting it to what I want.

Here is what I have so far (Much of it lifted straight the
"The depot":

Software packages would be in installed in a package directory,
I'm using "/depot" same as the paper.

Working with the example "perl", the installation on "server" would look like
Assuming a sun4 binary


        /export/depot/.primary/perl/plat-sun4-OS4/bin/perl
                                                 /h2p
                                                 /lib/perl/[bunch of stuff]

                                                 /README

The clients will "see" this as

        /depot/.primary/perl/plat/bin/perl
                                     /h2p
                                 /lib/perl/[bunch of stuff]

although I am thinking of just making it

        /depot/perl/bin/perl
                       /h2p
                   /lib/perl/[bunch of stuff]

I haven't thought through the side effect yet.

I intend to implement the client view via the automounter.

Aside:  I would expect that in this example that perl would be have
        been configured to expect itself to be installed
        in /depot/perl/bin (or /depot/.primary/perl/plat/bin)
        and to find it's libaries in /depot/perl/lib
        (/depot/.primary/perl/plat/lib)  This is make the packages
        "self-contained"

An "installation program" would then build symlinks so that 
there will be links in /usr/local that would look like:

        /usr/local/bin/perl     -> /depot/perl/bin/perl
                                                  /h2p
        /usr/local/lib/perl     -> /depot/perl/lib/perl

I expect to have a "deinstall" program to remove the symlinks also.

Issues that I am still uncertain are:

        o Shared libraries and associated problems
          lidl at eng.umd.edu (Kurt J. Lidl) mentioned this and I
          don't have a good understanding of how to deal with it.

        o Performance -- while I think it will be fine and several
          people have agreed, I don't have concrete data to back me
          this assertion up.  If someone can explain the "cost"
          a /usr/local/bin full of symlinks I would appreciate it.
          (I am hoping for something like:  In our environment of 100
          clients and 10 servers the extra overhead is about 2% extra stat
          traffic which is insignifant and delays in starting up
          are applications is tolerable)

I've also glossed over some very hard problems in using the automounter
for doing this.  I will probably bring those up as I get closer to
them.

Many of the ideas, terminology in the above description are adaptations
or blatant ripoffs of those presented in "The Depot:  A framework for
shareing software installation across organization and UNIX platform
boundaries" by Manheimer, Warsaw, Clark and Rowe.

I appreciate the feed back and comments that people have sent it so far.
-- 
Arnold de Leon  			arnold at synopsys.com
Synopsys Inc.				(415) 962-5051
1098 Alta Ave.
Mt. View, CA 94043