Wikimedia Engineering/Report/2013/May

Engineering metrics in May:
 * 124 unique committers contributed patchsets of code to MediaWiki.
 * The total number of unresolved commits went from about 815 to 960.
 * About 87 shell requests were processed.
 * Wikimedia Labs now hosts 165 projects and 1382 users; to date 1943 instances have been created.

Major news in May include:
 * An invitation from the Language engineering team to collaborate on language-related projects;
 * A new Notifications system enabled on the English Wikipedia;
 * Recent developments in language engineering, and the upcoming deployment of the Universal language selector on all wikis;
 * The start of a discussion around Flow, a proposed discussion system for Wikimedia sites;
 * A call for proposals to manage the MediaWiki release cycle;
 * An experience-sharing exercise by the Mobile engineering team about distributed collaboration;
 * "Nearby", a feature showing Wikipedia articles about nearby places on location-aware devices;
 * Tool Labs, which is now operational and ready to host tools migrated from the Toolserver;
 * A test wiki to try out new features in right-to-left languages
 * Tech news, a weekly tech newsletter to help users stay informed of technical changes going to impact them.

''Note: We're also providing a shorter, simpler and translatable version of this report that does not assume specialized technical knowledge.

Upcoming events
There are many opportunities for you to get involved and contribute to MediaWiki and technical activities to improve Wikimedia sites, both for coders and contributors with other talents.

For a more complete and up-to-date list, check out the Project:Calendar.

Work with us
Are you looking to work for Wikimedia? We have a lot of hiring coming up, and we really love talking to active community members about these roles.

Announcements

 * Alexandros Kosiaris joined the Technical Operations team as Operations Engineer (announcement).
 * May Galloway joined the Product Development team as Visual Designer (announcement).
 * Jared Zimmerman joined the Engineering Department as Director of User Experience (announcement).
 * Nik Everett joined the Platform engineering team as Senior Software Engineer specializing in Search (announcement).
 * Aarti Dwivedi, Anubhav Agarwal, Harsh Kothari, Himeshi De Silva, Jiabao Wu, Kiran Mathew Koshy, Liangent, Molly White, Moriel Schottlender, Nazmul Chowdhury, Nilesh Chakraborty, Or Sagi, Petr Onderka, Pragun Bhutani, Praveen Singh, Rahul Maliakkal, Richa Jain, Rohan Verma, Tongbo Sui and Yevheniy Vlasenko joined the Wikimedia tech community as part of Summer of Code 2013. Katie Cunningham and Rachel Thomas joined as part of the Outreach Program for Women.

Technical Operations
Site infrastructure
 * The migration to MariaDB continued, with Wikimedia Commons now fully moved over. Additional database infrastructure work was completed in support of the Tool Labs, producing a row-based replication stream with all PII removed for the publicly accessible Tool Labs databases.
 * We'll be upgrading to Request Tracker version 4 and migrating the service to Eqiad soon. Most of the ground work is laid for this; RT4 is puppetized and we've done a dry run.
 * Brandon Black made improvements to our Varnish cache invalidation code. Together with Mark Bergsma and Faidon Liambotis, they wrote a replacement for varnishhtcpd called vhtcpd, and deployed it to the production Varnish machines. The new daemon is ~50x more efficient at the same basic job. This buys us some performance on Varnish machines in general, but more importantly it gets rid of invalidation failures due to network buffer overruns when the old daemon couldn't keep up. This should also rid us from the random software failures in the old daemon that resulted in missing some or all cache purge requests for extended periods of time. The initial deployment has just been a basic swap of the two daemons. Further near-future improvements include turning on the new daemon's HTCP regex filtering configuration for more efficiency gains, and tying its HTCP packet statistics back into our normal monitoring and analysis infrastructure, so that we can better see any further multicast invalidation delivery issues that may arise.
 * Daniel Zahn led the OS patch release train; the team has started to upgrade about 50% of the servers to-date and will finish the rest in June.
 * Faidon also worked with Aaron Schulz and made Ceph at Eqiad the primary media storage back-end, leaving Swift at Tampa as a secondary fail-over back-end. This means that MediaWiki application servers were writing to & reading from there for about four & two weeks respectively. More recently, the cluster encountered some problems and traffic was temporarily reverted back to Tampa. Faidon is now upgrading Ceph software to the newer upstream version, Cuttlefish, which addresses a number of problems that were encountered during this time and were successfully reported to Ceph developers. Testing will resume after that happens, both by re-enabling Ceph as a MediaWiki back-end and by switching a portion of Varnish traffic to Ceph.
 * Mark and Faidon started working on migrating the Text Squid servers to use Varnish instead. In Mark's preliminary tests on 1 Esams and 4 Eqiad servers, the results look encouraging. He will start adding more traffic to them in the coming weeks.

Data Dumps
 * The routine dumps of Wikidata ran into two roadblocks, one of them related to the way that Recent changes patrol and autopatrolling are handled in MediaWiki. While a local workaround is in place, there has been discussion of revamping the patrolling mechanism including changes to the database . The other issue, affecting the full history content dumps, also has a temporary workaround until we can decide what the meaning of the  field in the database for revisions really means.
 * The mwxml2sql utils have been through some testing and bug fixes, and a volunteer is interested in packaging them for Debian to accompany his code for local installation of a mirror of Wikipedia (or the project of one's choice).
 * Incremental dumps will be developed this summer by User:Svick as part of this year's GSoC program. We're happy to have him and can't wait for the finished code!

Wikimedia Labs
 * This month was mostly dedicated to bringing Tool Labs online, but a number of other changes occurred as well. Work has progressed on AJAXification of the OpenStackManager interface. Instance reboot actions are now using this and there are gerrit changes awaiting review for instance console output, instance deletion, and some IP address actions. The custom virtual machine image had a number of fixes this month improving reliability and boot speed. We expect further improvements with upgrades to the OpenStack grizzly or havana releases. OpenStack was upgraded from the essex release to the folsom release, increasing speed of operations and bringing some new features (such as instance resizing). We'll be making these features available for use soon. All virtualization hosts and all instances were upgraded for a kernel security vulnerability and were rebooted this month, causing roughly an hour of scheduled downtime. Work has also been progressing on creating instances pre-configured for doing MediaWiki development; this has been working in the past, but it is now more reliable, faster, and meets our legal team's requirements for MediaWiki installations in Labs. Work has also progressed on a more reliable development environment for Labs itself. Soon it should be possible to install a pre-configured instance ready for making changes to the Labs infrastructure.
 * Tool Labs is now operational, with roughly 150 tools already migrated. With the completion of the basics of replication (all but s7 are operational), there remains no roadblocks for migration. During the week since the Amsterdam Hackaton, a fair number of minor issues have been found and fixed, and the general consensus from users is that the environment is functional. On the roadmap for the next month is cleaning up some of the management for replication (so that it is more generalized), finish s7, and help users with their migration issues.


 * Tool Labs work has also added a new feature available to all of Labs: service groups. Service groups are a user/group combination available locally within a project. Service group membership allows regular users to sudo to the service groups, allowing per-project service users, rather than needing to create local users via puppet, or create global users via wikitech.


 * Work progresses on puppetizing more OpenStack services and the OpenStackManager extension. Currently OSM development is hampered by a lack of test installs; soon we should have the ability to easily create new labs instances running Openstack and OpenStackManager for testing and development.

Kiwix
The Kiwix project is funded and executed by Wikimedia CH.


 * With openZIM, we have finally released the first version of its standard implementation code: the zimlib. Kiwix was introduced in Debian testing. A new release of Kiwix for Android, with a few bug fixes and improvements, was released. Our first GSoC project (ZIM incremental updates for Kiwix) was prepared and accepted; work has already started with Kiran, the Indian student responsible for this project.

Wikidata
The Wikidata project is funded and executed by Wikimedia Deutschland.


 * The Wikidata team worked on 2 major topics in May: the ability to access data from Wikidata in a Wikipedia article by its label and not just its ID, and the ability to enter points in time into Wikidata, which for example now makes it possible to enter the date of birth of a person. Magnus Manske blogged about the tool ecosystem that is building around Wikidata. During the next 3 months, the team will be working with 3 Google Summer of Code students, and 2 other students will be working with other organizations on Wikidata-related projects. The codebase has been reviewed by Qafoo. Wikidata-tech, a new mailing list for discussions related to the development around Wikidata, was created. Additionally, the team attended the hackathon in Amsterdam to give tutorials and meet other developers. A prototype of a multilingual map was built there, among other things.

Future

 * The engineering management team continues to update the Deployments page weekly, providing up-to-date information on the upcoming deployments to Wikimedia sites, as well as the engineering roadmap, listing ongoing and future Wikimedia engineering efforts.