GLEP 19: Gentoo Stable Portage Tree
|Kurt Lieber <email@example.com>
|2004-01-29, 2004-11-02, 2004-12-07, 2006-10-10
Withdrawn by the author. "If someone wants to take up the torch, more power to them, but they should probably start clean with a new glep."
This GLEP is intended to propose a series of changes to the Portage tree that are necessary to facilitate the use of Gentoo in areas where stability and predictability are of paramount importance, including servers in enterprise environments, mission critical workstations and other such installations.
The proposed solution involves creating a separate tree in Portage that is updated far less often than the regular tree. Outside of periodic updates, this tree would only be updated with critical bugfixes and security patches.
Enterprise users typically value stability and a predictable upgrade path over having the latest packages or features available to them. Historically, Gentoo Linux has been unable to provide such an environment due to the dynamic nature of the Portage tree.
The Gentoo Infrastructure team will need to provide an additional Portage tree on our rsync mirroring system. This new tree will house the ebuilds associated with the stable tree. It also impacts all Gentoo developers responsible for creating and updating ebuilds as they will be expected to integrate the tagging of ebuilds for the stable tree into their normal development process, both for the quarterly release cycles as well as off-cycle bug and security fixes.
The Gentoo Documentation team will also be affected as they will be responsible for updating installation documents to take these new features into account.
A basic outline of various ways of adding a "stable" tree to Portage was discussed in the gentoo managers meeting on 26-Jan-04. Consensus seemed to be reached that such a solution was needed and that branching the gentoo-x86 repository was the appropriate way to accomplish this. The largest area of disagreement surrounded how specific ebuilds should be targeted for inclusion in the stable tree.
One suggested solution was a simple branch of the CVS tree and having developers work in two separate branches; one for the stable tree and another for the traditional tree. However, it was felt this would prove too cumbersome in practice.
Another suggestion was to have a small group of dedicated gentoo-server developers responsible for generating the contents of the stable tree, which would provide more control and quality assurance over the ebuilds added to the stable tree. While this might prove effective for a small number of ebuilds, it is quite likely that this model would not scale enough to allow for a large number of ebuilds in the stable tree and, over time, the project would become resource constrained and unable to meed future deadlines.
While the original draft of this GLEP called for the creation of a stable keyword, we have since discarded that idea in favor of creating a custom profile, which will be used to track a subset of packages and versions.
This GLEP will create a new set of cascaded profiles (one per release, not to exceed two per year) which will contain a subset of packages, including versions. This profile will "pin" a Gentoo Linux box to a specific set of packages and will only be updated for security updates and, in rare circumstances, major bug fixes.
Because this profile will be cascaded, the option exists for other developers to create their own profile, containing a subset of packages not found in the "main" stable tree and include those as part of the overall stable profile. These cases will be treated on a one-off basis.
The initial version will be x86 only, though other people will be encouraged to provide separate stable profiles for other arches. It is expected that any effort to provide a stable tree for any arch or flavor of Gentoo will follow the basic outline of this GLEP to ensure consistency for our users.
In addition to a custom profile, this GLEP will also create a separate rsync repository, "gentoo-stable-portage", which will be available on all servers in the rsync.gentoo.org rotation. This repository will be identical to the main gentoo-portage repository except that the --delete flag will be removed from the rsync option that populates the tree. This will ensure that users of the stable profile will not have to worry about ebuilds for their packages disappearing.
Stable profiles will be maintained on an N - 2 basis. That is to say that we will maintain a stable profile for the most current release, plus the previous two releases. With the expected release schedule for 2005, this will result in each profile being supported for approximately 18 months. Future versions of the stable portage tree may seek to increase the life of these profiles.
All features proposed here are new additions to existing processes and features. There should be no impact on existing features and functionality.