[gentoo-user] Sync'ing and compiling pkgs for multiple PCs

[Simon]

Hi,
   Below I explain my story, I show some difficulties and near the end ask a few 
questions, but last paragraph is my main question, comments on the rest is 
greatly appreciated.

   I have 3 computers and they are all setup the same with the exception of the 
kernel that has different options for the youngest of my pcs.  I'm looking for a 
simple, easy and efficient way to keep them all up2date.

   I want to avoid 3 --sync to the gentoo servers.  I have tried to setup one of 
my pc as central server and sync the others on it, but has the main disadvantage 
that the other PCs are dependant on it (ok, it's not so difficult to change 
make.conf).

   Then, I would have to compile approximately 3 times the same software.  My 
computers are slow, I am poor, can't buy new hardware (FORGET IT).  So I tried 
turning on buildpkg and compile on my fastest PC.

   I already use unison to sync my /home directory through ssh, i use it because 
it is simple and does exactly what I need out of the box.  (Compared to rsyncd, 
where you need to setup a server, setup the firewall, what about security?...).
   Anyway, I decided to sync /usr/portage with unison as well, which worked fine 
and I had the binpkgs on the other pc.  When I did an `emerge -k -uDN world` I 
found that many packages still had to be built.  I extracted the list of 
packages and versions, formated properly and emerged them all on my fastest pc, 
ran through the same routine and at the end I had to recompile just a few 
packages that I let run (nothing like gcc or glibc, hehe).

   Now, with my "unison technique" I believe the only flaw was that I didn't 
have the list of all packages on all my PCs and I wonder if there is a way to 
generate such a list, similar to what `emerge -vp -uDN world` gives but in a 
format ready for emerge, so I can dump the pkg list for the 3 pc in 3 files and 
run emerge on those 3 files.  I would compile them -1, which, as I understand it 
would upgrade my system (upgrade but not change world entries) and install 
unneeded packages around.  I would then use --depclean which would remove the 
unneeded packages cleanly and finally revdep-rebuild.  I would be left with my 
fastest pc's world up2date + all binpkgs of all 3 pcs.

   The advantage of my "unison technique" is it's transparent to any 3 pc, if a 
pkg is not there, it downloads the distfile from the internet and compiles it, 
completely independant.  Just doing the --sync requires a little bit of 
consideration.

   I'm wondering if there is (i'm sure there is) a better practice in the 
compilation of binpkgs for use by multiple computers, so that none of the other 
computers will compile (quick update for them) and that the compiling computer 
can compile all needed pkgs in one run preferably.

As usual, if you can answer my question directly on the mailing list that'd be 
nice, if you could give URLs to some documentation that answers my question 
that'd be very nice too!

Thanks,  Simon