Catalyst

is Article description::Gentoo's release building tool. With users are able to completely customize a Gentoo install by customizing the very tools that are used to install a system. Official Gentoo Linux release media is built using Catalyst.

is capable of:


 * Building installation stages.
 * Building bootable LiveCDs.
 * Building netboot images.

Emerge
To install, run:

Configuration
After emerging, the first (and probably only) configuration step is to edit

Seed tarball
For creating a stage3 a seed tarball is needed. Catalyst will into the seed and  the packages for the new stages inside it, so it does not pollute the build system.

The seed tarball should be placed in the following temporary directory unless the temporary directory location was modified during the Catalyst configuration in the configuration section above. If the temporary directory was modified put the seed in the appropriate directory, otherwise:

The seed tarball can be a current stage3 tarball downloaded from one of the Gentoo mirrors.

Relatively recent tarballs can be found here, and tarballs can be found here.

Use to download from the command line. For example, to download an tarball:

Local generation
Along with the tarball a snapshot of the Portage tree is required. Catalyst can create a snapshot of the system's current directory with the  command.

The snapshot will be saved to

In the example below  (April, 2015 in an easy to read command-line format) is the argument passed to the   option as the snapshot date:

The  argument can be any date format that makes sense to the user. To use the current year/month following format above, simply:

Remote download
Another option is to use one of the Portage tree snapshots available on the mirrors. Current snapshots can be found here.

As mentioned above, the command can be used to download a remote snapshot hosted on a HTTP(S) server:

Specs
Catalyst uses specs files for reading the parameters to create a stage. For building a stage3 a stage1 and stage2 must be built, then the stage3 will be created. Therefore a spec file is needed for each of the stages.

The specs the Gentoo Release team use for autobuilds can be found in the RelEng git repository:

https://gitweb.gentoo.org/proj/releng.git/tree/releases/specs

This article will use the specs for :

https://gitweb.gentoo.org/proj/releng.git/plain/releases/specs/amd64/

Download the three files above. These specs are very simple; all three of them contain many of the same parameters.

Inside a file
Check out the file:

.spec file option list
The following table provides a list of file options and their descriptions.

On and  files,   needs to reference the stage1 and stage2 tarballs respectively. In other words, with exception of the first file in the sequence,   should be set to the tarball build previously. For an example, if 2015.04 was used as the, the   for stage2 should be: default/stage1-amd64-2015.04, and the   for stage3 should be: default/stage2-amd64-2015.04.

Building
Once the specs have been reviewed, start by running the following command:

If everything went as expected a stage3 should be show up in the directory.