Wikimedia Release Engineering Team/Trainsperiment week/gu

🚂🧪 Trainsperiment Week - March 21, 2022.

Four deployment trains. One week. Six nervous Release Engineers!

આ શું છે!?
The "deployment train" is the name of the process where the Release Engineering Team (RelEng) deploys between 150–950 patches to the ~980 Wikimedia wikis, in 3 stages. There is usually one train each week.

There will be four deployment trains during the week of Monday, 21 March 2022.

This is a one-week experiment to gather data for possible future changes.

If you have ideas or thoughts, please add them on the talk page. 💡

Visualization
These images show the difference between the regular process and this new experimental process:

🤔 Unknowns
Here is a list of things we are thinking about. If you can help with any of these: please talk to us!


 * How will more trains affect caches and site performance? (T303758)
 * Are developers going to need to be more mindful of forward and backward compatibility? (T303759)
 * How will train-rollback work with blockers? This one is on us, but we’ll be figuring it out as we go. (T303747)
 * Will blocker tasks be too confusing with so many trains?
 * Is this sustainable?

🏆 Goals
Our goal is a shorter time between when developers write code and when that code gets live traffic. We believe the benefits of that are:


 * A more accurate mental model of the current state of the code that is "live" will make development easier
 * A smaller amount of code per release, will make the releases easier to debug and test
 * It will make it easier for developers to fix bugs in a release if the context is still fresh in their heads

📅 Schedule
Monday, 21 March 2022 #

Tuesday, 22 March 2022 #

Wednesday, 23 March 2022 #

Thursday, 24 March 2022 #