## Distributing pkgsrc builds across different OSes

You may want to use several machines to speed up your *pkgsrc* builds, but
as those computers are not running NetBSD, you may think they are useless as
build-helpers. This is where enters NetBSD's *cross-compiling* system in
conjunction with [distcc](http://code.google.com/p/distcc/).

### A classic scenario

GNU/Linux is a very common OS you probably have on your network, in this
tutorial, we will focus on how to use a Debian GNU/Linux system as a
*distcc* node, but this procedure can apply to almost any pkgsrc-supported
platform.

First things first, your GNU/Linux machine must have the following packages
installed

* gcc
* g++
* zlib1g-dev
* ncurses-base

### Building the cross-compiling chain

Once done, download NetBSD's source tree. For example, if your target is a
NetBSD 5.1.2 system

	# pwd
	/home/netbsd
	# cvs -d anoncvs@anoncvs.fr.netbsd.org:/cvsroot co -rnetbsd-5-1-2-RELEASE src

We will then use the *build.sh* script in order to build the tools needed
for cross-compiling

	# cd src
	# ./build.sh -m amd64 tools

Do *not* use the *-u* flag, as we need to configure *nbcompat* for the tools
to build correctly.

Once finished, you should have a directory like

	tooldir.Linux-2.6.32-5-xen-amd64-x86_64

On the *src* directory. This is where the cross-compiling toolkit resides.

### Installing and configuring distcc

It is mandatory to configure *distcc* so it uses our cross-comping tools to
build binaries for another platform. On a Debian system, this is done in
*/etc/default/distcc*

	STARTDISTCC="true"
	# [...]
	# Allowed networks
	ALLOWEDNETS="127.0.0.1 192.168.0.0/24"
	# IP where distcc will listen
	LISTENER="192.168.0.7"
	###
	# Here's the real trick, supersede $PATH so the firsts binaries
	# distcc will look for are NetBSD's ones
	###
	PATH=/home/netbsd/src/tooldir.Linux-2.6.32-5-xen-amd64-x86_64/x86_64--netbsd/bin:$PATH

After that, simply start *distcc*

	/etc/init.d/distcc start

### Testing the setup

On a NetBSD machine located in *distcc*'s allowed network, add the following to
*/etc/mk.conf*

	PKGSRC_COMPILER=ccache distcc gcc
	MAKE_JOBS=4
	DISTCC_HOSTS=192.168.0.7 localhost

And fire up the *make* command in a *pkgsrc* subdirectory containing a C-based
package. You should see something like this in helper's */var/log/distccd.log*
file

	distccd[20634] (dcc_job_summary) client: 192.168.0.2:64006 COMPILE_OK exit:0 sig:0 core:0 ret:0 time:57ms gcc /usr/pkgsrc/misc/tmux/work/.ccache-cache/tmp/unvis.tmp.bulkor.18298.i
	distccd[20734] (dcc_job_summary) client: 192.168.0.2:64005 COMPILE_OK exit:0 sig:0 core:0 ret:0 time:172ms gcc /usr/pkgsrc/misc/tmux/work/.ccache-cache/tmp/imsg-buffe.tmp.bulkor.20945.i
	distccd[20586] (dcc_job_summary) client: 192.168.0.2:64004 COMPILE_OK exit:0 sig:0 core:0 ret:0 time:40ms gcc /usr/pkgsrc/misc/tmux/work/.ccache-cache/tmp/strtonum.tmp.bulkor.4879.i

Of course, you may want to adjust the *MAKE_JOBS* according to the number of
nodes your build-cluster has.

### pbulk and distcc

If you intend to use distributed build while running
[pbulk](http://wiki.netbsd.org/tutorials/pkgsrc/pbulk/), you **must** add the
following to the */etc/mk.conf* of your *sandbox*

	.for DISTCCDEPS in devel/ccache sysutils/checkperms pkgtools/digest devel/distcc devel/popt devel/libtool-base lang/f2c devel/gmake
	.	if ${PKGPATH} == ${DISTCCDEPS}
	IGNORE_DISTCC=	yes
	IGNORE_CCACHE=	yes
	.	endif
	.endfor

Or the scanning phase will end up with circular dependencies

	Cyclic dependency for package:
	ccache-3.1.4nb1
	checkperms-1.11
	digest-20111104
	distcc-3.1nb1
	popt-1.16nb1
	libtool-base-2.2.6bnb5
	f2c-20100903
	ccache-3.1.4nb1

Enjoy your faster builds!