launchpadblog

Here’s a brief changelog for this month.

(more…)

Well, it’s been a while!  Since we last posted a general update, the Launchpad team has become part of Canonical’s Online Services department, so some of our efforts have gone into other projects.  There’s still plenty happening with Launchpad, though, and here’s a changelog-style summary of what we’ve been up to.

(more…)

Here’s what the Launchpad team did in October.

(more…)

If you are a member of Launchpad’s beta testers team, you can now try out webhooks for Bazaar branches and Git repositories. These can be used to set up integration with external sites for various purposes, such as running CI jobs or publishing documentation. We expect to open this up to all Launchpad users soon, but in the meantime please do file a bug against Launchpad itself if you encounter any problems.

See our webhooks documentation for more details.

Update: as of 2015-11-20, this feature is enabled for all Launchpad users.

October already! As the leaves start to turn red here in the northern hemisphere, here’s a brief summary of what we did in September.

(more…)

Here’s a summary of what the Launchpad team got up to in August.

(more…)

Here’s a summary of what the Launchpad team got up to in July.

(more…)

It’s been a while since we posted much regularly on this team blog, not least because for a while Launchpad was running more or less in maintenance mode.  That’s no longer the case and we’re back to the point where we can do feature development work again, as exemplified by our recent addition of Git code hosting support.

Lots of other things have been happening in the Launchpad world lately, though, and the half-way point in the year seems like a good time to start talking about them.  I’m going to try to do this a bit more regularly, aiming for about once a month when we also update our internal stakeholders.  This post covers roughly the last three months.

(more…)

Today we’re announcing early support for hosting Git repositories directly on Launchpad, as well as or instead of Bazaar branches. This has been by far the single most commonly requested feature from Launchpad code hosting for a long time; we’ve been working hard on it for several months now, and we’re very happy to be able to release it for general use.

This is distinct from the facility to import code from Git (and some other systems) into Bazaar that Launchpad has included for many years. Code imports are useful to aggregate information from all over the free software ecosystem in a unified way, which has always been one of the primary goals of Launchpad, and in the future we may add the facility to import code into Git as well. However, what we’re releasing today is native support: you can use git push to upload code to Launchpad, and your users and collaborators can use git clone to download it, in the same kind of way that you can with any Git server.

Our support is still in its early stages, and we still have several features to add to bring it up to parity with Bazaar hosting in Launchpad, as well as generally making it easier and more pleasant to use. We’ve released it before it’s completely polished because many people are clamouring to be able to use it and we’re ready to let you all do so. From here on in, we’ll be adding features, applying polish, and fixing bugs using Launchpad’s normal iterative deployment process: changes will be rolled out to production once they’re ready, so you’ll see the UI gradually improving over time.

What’s supported?

You can:

• push Git repositories to Launchpad over SSH
• clone repositories over git://, SSH, or HTTPS
• see summary information on repositories and the branches they contain in the Launchpad web UI
• follow links from the Launchpad web UI to a full-featured code browser (cgit)
• push and clone private repositories, if you have a commercial subscription to Launchpad
• propose merges from one branch to another, including in a different repository, provided that they are against the same project or package

What will be supported later?

Launchpad’s Bazaar support has grown many features over the years, and it will take some time to bring our Git support up to full parity with it and beyond. Git repositories use a somewhat different model from Bazaar branches, which we’ve had to account for in many places, and some facilities will require complete reimplementation before we can support them with Git.

Here’s an incomplete list of some of the features we hope to add:

• useful subscriptions (currently only attribute change notifications work, which are not usually very interesting in themselves)
• RSS feeds
• mirroring
• webhooks
• an integrated code browser

See our help page for more known issues and instructions on using Launchpad with Git.

Helping out

This is a new service, and we welcome your feedback: you can ask questions in #launchpad on freenode IRC, on our launchpad-users mailing list, or on Launchpad Answers, and if you find a bug then please tell us about that too.

Launchpad is free software, licensed under the GNU AGPLv3. We’d be very happy to mentor people who want to help out with parts of this service, or to build things on top of it using our published API. Some preliminary documentation on this is on our developer wiki, and you can always contact us for help.

We’ve made a number of improvements to the Launchpad build farm in the last month, with the aim of improving its performance and robustness.  This sort of work is usually invisible to users except when something goes wrong, so we thought it would be worth taking some time to give you a summary.  Some of this work was on the Launchpad software itself, while some was on the launchpad.net hardware.

(To understand some of the rest of this post, it’s useful to be aware of the distinction between virtualised and devirtualised builders in Launchpad.  Virtualised builders are used for most PPAs: they build untrusted code in a Xen guest which is initialised from scratch at the start of each build, and are only available for i386, amd64, and a small number of ARM builds by way of user-mode QEMU.  Devirtualised builders run on ordinary hardware with less strict containment, and are used for Ubuntu distribution builds and a few specialised PPAs.)

ARM builders have been a headache for some time.  For our devirtualised builders, we were using a farm of PandaBoards, having previously used BeagleBoards and Babbage boards.  These largely did the job, but they’re really a development board rather than server-class hardware, and it showed in places: disk performance wasn’t up to our needs and we saw build failures due to data corruption much more frequently than we were comfortable with.  We recently installed a cluster of Calxeda Highbank nodes, which have been performing much more reliably.

It has long been possible to cancel builds on virtualised builders: this is easy because we can just reset the guest.  However, it was never possible to cancel builds on devirtualised builders: killing the top-level build process isn’t sufficient for builds that are stuck in various creative ways, and you need to make sure to go round and repeatedly kill all processes in the build chroot until they’ve all gone away.  We’ve now hooked this up properly, and it is possible for build daemon maintainers to cancel builds on devirtualised builders without operator assistance, which should eliminate situations where we need urgent builds to jump the queue but can’t because all builders are occupied by long-running builds.  (People with upload privileges can currently cancel builds too, which is intended mainly to allow cancelling your own builds; please don’t abuse this or we may need to tighten up the permissions.)  As a bonus, cancelling a build no longer loses the build log.

Finally, we have been putting quite a bit of work into build farm reliability.  A few problems have led to excessively long queues on virtual builders:

• Builders hung for some time when they should have timed out, due to a recent change in su; this is now fixed in the affected Ubuntu series.
• Xen guests often fail to restore for one reason or another, and when this happened builders would fail in ways that required an operator to fix.  We had been dealing with this by having our operators do semi-automatic builder fixing runs a few times a day, but in recent months the frequency of failures has been difficult to keep up with in this way, especially at the weekend.  Some of this is probably related to our current use of a rather old version of Xen, but the builder management code in Launchpad could also handle this much better by trying to reset the guest again in the same way that we do at the start of each build.  As of this morning’s code deployment, we now do this, and the build farm seems to be holding up much more robustly.

This should make things better for everyone, but we aren’t planning to stop here.  We’re intending to convert the virtual builders to an OpenStack deployment, which should allow us to scale them much more flexibly.  We plan to take advantage of more reliable build cancellation to automatically cancel in-progress builds that have been superseded by new source uploads, so that we don’t spend resources on builds that will be rejected on upload.  And we plan to move Ubuntu live file system building into Launchpad so that we can consolidate those two build farms and make better use of our available hardware.