Released OpenStack Newton, Moving OpenStack packages to upstream Gerrit CI/CD

OpenStack Newton is released, and uploaded to Sid

OpenStack Newton was released on the Thursday 6th of October. I was able to upload nearly all of it before the week-end, though there was a bit of hick-ups still, as I forgot to upload python-fixtures 3.0.0 to unstable, and only realized it thanks to some bug reports. As this is a build time dependency, it didn’t disrupt Sid users too much, but 38 packages wouldn’t build without it. Thanks to Santiago Vila for pointing at the issue here.

As of writing, a lot of the Newton packages didn’t migrate to Testing yet. It’s been migrating in a very messy way. I’d love to improve this process, but I’m not sure how, if not filling RC bugs against 250 packages (which would be painful to do), so they would migrate at once. Suggestions welcome.

Bye bye Jenkins

For a few years, I was using Jenkins, together with a post-receive hook to build Debian Stable backports of OpenStack packages. Though nearly a year and a half ago, we had that project to build the packages within the OpenStack infrastructure, and use the CI/CD like OpenStack upstream was doing. This is done, and Jenkins is gone, as of OpenStack Newton.

Current status

As of August, almost all of the packages Git repositories were uploaded to OpenStack Gerrit, and the build now happens in OpenStack infrastructure. We’ve been able to build all packages a release OpenStack Newton Debian packages using this system. This non-official jessie backports repository has also been validated using Tempest.

Goodies from Gerrit and upstream CI/CD

It is very nice to have it built this way, so we will be able to maintain a full CI/CD in upstream infrastructure using Newton for the life of Stretch, which means we will have the tools to test security patches virtually forever. Another thing is that now, anyone can propose packaging patches without the need for an Alioth account, by sending a patch for review through Gerrit. It is our hope that this will increase the likeliness of external contribution, for example from 3rd party plugins vendors (ie: networking driver vendors, for example), or upstream contributors themselves. They are already used to Gerrit, and they all expected the packaging to work this way. They are all very much welcome.

The upstream infra: nodepool, zuul and friends

The OpenStack infrastructure has been described already in, by Ian Wienand. So I wont describe it again, he did a better job than I ever would.

How it works

All source packages are stored in Gerrit with the “deb-” prefix. This is in order to avoid conflict with upstream code, and to easily locate packaging repositories. For example, you’ll find Nova packaging under Two Debian repositories are stored in the infrastructure AFS (Andrew File System, which means a copy of that repository exist on each cloud were we have compute resources): one for the actual deb-* builds, under “jessie-newton”, and one for the automatic backports, maintained in the deb-auto-backports gerrit repository.

We’re using a “git tag” based workflow. Every Gerrit repository contains all of the upstream branch, plus a “debian/newton” branch, which contains the same content as a tag of upstream, plus the debian folder. The orig tarball is generated using “git archive”, then used by sbuild to produce binaries. To package a new upstream release, one simply needs to “git merge -X theirs FOO” (where FOO is the tag you want to merge), then edit debian/changelog so that the Debian package version matches the tag, then do “git commit -a –amend”, and simply “git review”. At this point, the OpenStack CI will build the package. If it builds correctly, then a core reviewer can approve the “merge commit”, the patch is merged, then the package is built and the binary package published on the OpenStack Debian package repository.

Maintaining backports automatically

The automatic backports is maintained through a Gerrit repository called “deb-auto-backports” containing a “packages-list” file that simply lists source packages we need to backport. On each new CR (change request) in Gerrit, thanks to some madison-lite and dpkg –compare-version magic, the packages-list is used to compare what’s in the Debian archive and what we have in the jessie-newton-backports repository. If the version is lower in our repository, or if the package doesn’t exist, then a build is triggered. There is the possibility to backport from any Debian release (using the -d flag in the “packages-list” file), and even we can use jessie-backports to just rebuild the package. I also had to write a hack to just download from jessie-backports without rebuilding, because rebuilding the webkit2gtk package (needed by sphinx) was taking too resources (though we’ll try to never use it, and rebuild packages when possible).

The nice thing with this system, is that we don’t need to care much about maintaining packages up-to-date: the script does that for us.

Upstream Debian repository are NOT for production

The produced package repositories are there because we have interconnected build dependencies, needed to run unit test at build time. It is the only reason why such Debian repository exist. They are not for production use. If you wish to deploy OpenStack, we very much recommend using packages from distributions (like Debian or Ubuntu). Indeed, the infrastructure Debian repositories are updated multiple times daily. As a result, it is very likely that you will experience failures to download (hash or file size mismatch and such). Also, the functional tests aren’t yet wired in the CI/CD in OpenStack infra, and therefore, we cannot guarantee yet that the packages are usable.

Improving the build infrastructure

There’s a bunch of things which we could do to improve the build process. Let me give a list of things we want to do.

  • Get sbuild pre-setup in the Jessie VM images, so we can win 3 minutes per build. This means writing a diskimage-builder element for sbuild.
  • Have the infrastructure use a state-of-the-art Debian ftp-sync mirror, instead of the current reprepro mirroring which produces an unsigned reprository, which we can’t use for sbuild-createchroot. This will improve things a lot, as currently, there’s lots of build failures because of mirror inconsistencies (and these are very frustrating loss of time).
  • For each packaging change, there’s 3 build: the check job, the gate job, and the POST job. This is a loss of time and resources, as we need to build a package once only. It will be hopefully possible to fix this when the OpenStack infra team will deploy Zuul 3.

Generalizing to Debian

During Debconf 16, I had very interesting talks with the DSA (Debian System Administrator) about deploying such a CI/CD for the whole of the Debian archive, interfacing Gerrit with something like dgit and a build CI. I was told that I should provide a proof of concept first, which I very much agreed with. Such a PoC is there now, within OpenStack infra. I very much welcome any Debian contributor to try it, through a packaging patch. If you wish to do so, you should read how to contribute to OpenStack here: and then simply send your patch with “git review”.

This system, however, currently only fits the “git tag” based packaging workflow. We’d have to do a little bit more work to make it possible to use pristine-tar (basically, allow to push in the upstream and pristine-tar branches without any CI job connected to the push).

Dear DSA team, as we now nice PoC that is working well, on which the OpenStack PKG team is maintaining 100s of packages, shall we try to generalize and provide such infrastructure for every packaging team and DDs?