Fwd [2]: How to admin a multiple Gentoo Installation (and keep your sanity)

Here's the other message. This is awesome, though also a lot of work. I
love the way they deal with multiple architectures. Seems like he had to
script around a number of awkward things; I wonder what could be done to
make it easier? AfC

-----Forwarded Message-----
From: Andrea Barisani <[email protected]>
To: [email protected]
Subject: [gentoo-user] How to admin a multiple Gentoo Installation (and keep your sanity)
Date: 15 Mar 2003 16:55:09 +0100


Hi to all!

After having migrated from RedHat Linux to Gentoo on my network (35 hosts + 4
servers, approx 300 users) I would like to share and discuss my experiences
in handling multiple Gentoo systems installations. This is nothing special
for all the sysadmin out there, however I hope to stimulate discussion and
hear how you manage such installations.

- Scenario

35 client hosts used by our students handled by a central server, three
different architectures: k6 (400 Mhz), p1 (200 Mhz), p4 (1,7 Ghz).

- Primary objectives

1) have a centralized control of all clients installation and administration
2) find a proper way to optimize the installation on slow machines (p1 and k6)
3) give the users always the (almost) latest versions of all packages

Of course Gentoo was the answer :) and since it performs so well on our servers
we have decided to test it and eventually migrate all clients. (with Gentoo
performance on slow hardware has _really_ improved)

- Description

The system is composed by the 35 hosts and a central server that compiles and
propagates all packages to the clients, this is done by having 3 different
installations (one for each arch) in three different directories on the
server, packages are built with the '-b' option and then copied and installed
with 'emerge -k' on the clients. Packages and configurations propagation is
all done via rsync.

Let's see some details:

On the central server we got:

/dist/k6 
/dist/p1
/dist/p4

untar stage1 and bootstrap and compile the desired installation in each
directory with the proper arch-dependent optimizations. Since the server 
is a Gentoo installation I've used a single /usr/portage:

mount -o bind /usr/portage /dist/k6/usr/portage
mount -o bind /usr/portage /dist/p1/usr/portage
mount -o bind /usr/portage /dist/p4/usr/portage

Put any global modified/added file in /dist/adm/GLOBAL/, for example:

/dist/adm/GLOBAL/etc/fstab
/dist/adm/GLOBAL/boot/grub/grub.conf
/dist/adm/GLOBAL/usr/kde/3.1/share/config/kdm/kdmrx

...and so on

Put any arch-dependent modified/added file in /dist/adm/ARCH/, for example:

/dist/adm/ARCH/k6/etc/make.conf
/dist/adm/ARCH/p1/etc/make.conf
/dist/adm/ARCH/p4/etc/make.conf

...and so on

Put any host-dependent modified/added file in /dist/adm/LOCAL/, for example:

/dist/adm/LOCAL/host1/etc/conf.d/net
/dist/adm/LOCAL/host2/etc/conf.d/net

...and so on

Then put all clients hostnames divided by arch in k6.list, p4.list, p1.list
and put every hostname in all.list.

Now you can sync each configuration with the following scripts. 
The first argument is the arch (es. ./rsync-adm k6). These are not
the real scripts, only the core part is shown, I've omitted arguments
verification and some debugging 'echo' :).

rsync-adm:
/usr/bin/rsync -vrlptgoD --progress /dist/adm/GLOBAL/ /dist/$1/
/usr/bin/rsync -vrlptgoD --progress /dist/adm/ARCH/$1/ /dist/$1/

rsync-host:
for i in `cat /dist/$1.list` ; do
	/usr/bin/rsync -vrlptgoD --progress -e ssh /dist/adm/GLOBAL/ root@$i:/ ;
done

for i in `cat /dist/$1.list` ; do
	/usr/bin/rsync -vrlptgoD --progress -e ssh /dist/adm/ARCH/$1/ root@$i:/ ; 
	/usr/bin/rsync -vrlptgoD --delete --progress -e ssh /dist/$1/packages/ root@$i:/packages/ ;
	# my PKGDIR is /packages 
done

for i in `cat /dist/$1.list` ; do
	/usr/bin/rsync -vrlptgoD --progress -e ssh /dist/adm/LOCAL/$i/ root@$i:/ ;
done

Now on the clients you can mount via NFS in read-only /usr/portage.
However the subdir /usr/portage/distfiles/cvs-src must be writable, a way to
manage this is creating /tmp/portage and use /usr/portage/distfiles/cvs-src
as a mounting point:

mkdir /tmp/cvs-src ; chown root.portage /tmp/cvs-src ; chmod 4770 /tmp/cvs-src
mount -o bind /tmp/cvs-src /usr/portage/distfiles/cvs-src

Now packages update and installation can be done like the following:

# emerge sync
# chroot /dist/p4
# emerge -b -u --deep world
# emerge distcc
# exit
# for i in `cat /dist/p4.list` ; do ssh $i 'emerge -k -u --deep world' ; done
# for i in `cat /dist/p4.list` ; do ssh $i 'emerge -k distcc' ; done

- Caveats

openoffice-bin must be installed on the clients, it doesn't work with -b and
-k, I don't know why however I'll investigate, same problem with mplayer.

- Notes

The first idea was maintaining only /dist/arch installations and directly
rsync that tree on the clients, however on slow hardware this is really slow
and the exceptions (/var, /etc/mtab..etc) are too difficult to manage.


Hope that someone might find this useful, I'll be happy to hear your comments.

Bye :)

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