Home > Open source, Openstack, Ubuntu, Ubuntu Server > Upstream projects vs. Distributions

Upstream projects vs. Distributions

February 28, 2011 Leave a comment Go to comments

You can globally split open source projects into two broad categories. Upstream projects develop and publish source code for various applications and features. Downstream projects are consumers of this source code. The most common type of downstream projects are distributions, which release ready-to-use binary packages of these upstream applications, make sure they integrate well with the rest of the system, and release security and bugfix updates according to their maintenance policies.

The relationship between upstream projects and distributions is always a bit difficult, because their roles overlap a bit. Since I’m sitting on both sides of the fence, let’s try to find common ground.

Overlapping roles

In an ideal world, everyone would install software through distribution packages, and the roles wouldn’t overlap. In the real world though, upstream projects need to deal with distributions that don’t provide packages for your software, or provide old buggy versions with no mechanism for getting fresh ones. That’s why they need to care about manual installation or update mechanisms. On the other hand, in their rush to release fixes, distributions sometimes carry patches without sending them upstream immediately. Both want to provide bugfix updates to stable versions. In all cases the overlapping roles end up duplicating work and creating unnecessary friction.

Splitting the roles

In my (humble) opinion, upstream projects should encourage the use of packaged software wherever possible, rather than resisting it. They should concentrate on their core competency: working on producing new releases of their code. Dealing with distribution issues, environment specificities or maintaining stable branches is a different type of work, and one that distributions excel in. So the key seems to be in splitting the roles more cleanly.

Upstream projects should release code, together with good documentation on how to manually deploy it: dependencies, startup and upgrade mechanisms, open bug trackers with links to patches… This documentation can be reused by manual deployers and distribution packagers alike. They should stop short of providing installers, auto-updaters, dependency bundles, etc. They should limit the release of point release updates only to critical issues (data loss, security…).

Distributions should be responsible for proper packaging (easy way to install the software and its dependencies, together with startup scripts and other system integration), and would be responsible for more general bugfix updates that match their maintenance policy.

With such a split, you obviously will end up with a subpar user experience if you try to manually install the software from the released code. But you facilitate packaging, so you should end up being packaged in more distributions. I think time is better spent contacting distributions to get packaged rather than trying to improve the manual installation to the point where it is actually usable.

Freshness

One case where you end up doing manual installations (even on supported distributions) is to get the latest released code running on already-released distributions. Due to stable release policies in distributions, they will release bugfix updates for the version that was available when they released, but usually won’t provide a whole new version of a package.

The solution is in specific distribution archives that track the latest upstream releases (like PPAs in Ubuntu) and make them available for users of already-released distributions. Those are usually co-maintained between distributions and upstream projects.

Reference distributions

At this point, it is worth taking collaboration one step further, and have developers that are involved in both projects ! Those can make sure the distribution includes the packages and patches you need for your software to run properly. Those can make sure the distribution is one on which your software is up-to-date, runs properly and gets appropriate bugfix updates. Those can maintain the specific distribution archives for the latest upstream releases.

That distribution can then become a reference distribution for the upstream project, one that is tightly integrated with the upstream project and lives in harmony.

Two closing remarks:

  • You can have multiple reference distributions. That said, one way to limit friction and increase freshness is to have somewhat-synchronized release cycles, which may not scale very well.
  • I realize the proposed role split and reference distro scheme might not be generally applicable to all open source upstream projects. In my experience it worked well with server software.

In OpenStack, having a few Ubuntu core developers in the project (and the Ubuntu server team supporting us) allows us to use Ubuntu as a reference distribution. We have packages up for other distributions, but those are not (yet) official distribution packages. Any other distro developers interested to join ?

  1. oiaohm
    February 28, 2011 at 12:21

    Really correct answer is neither.

    1 common package system for all distributions is required. This will come in one form or another without distributions taking part.

    Fix ld.so so it support multi versions of the same lib installed. This would also go a long way to solving dependancy hell issues. Ie person need a old verison of 1 program and a new verison of another. Problem common dependancy must be different versions. Yet common dependancy does not have config files or anything else global. Ie other than the ld.so and the package manager designs not allowing this it should work perfect.

    Remember with Windows and OS X. Upstream part can release directly to downstream part without issue.

    “security and bugfix updates according to their maintenance policies.” This is how to drive upstream nuts when this is done without upstream approval. Reason downstream ends up with a stack of strange bugs caused by non approved alterations that end up reported upstream.

    Upstream needs to be in charge of all bugfix and secuirty patches. Since they are the core developers they are the best people to tell you if a patch will or will not work. Fedora has the right policy here. Distributions must work closely with upstream with patches. Failure todo so brings failure.

    Lot of distribution maintainers need to be told get there fingers out the cookie jar as well. For example Back porting bits from the development tree that are not fully tested yet. Only causes pain.

    Really ideal is no Distribution maintainers at all. Instead package management moves to a complete job in the upstream. This could save build time as well.

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