Reduce Rails app boot times
Acknowledging that while many people have done a lot of work on reducing Rails boot times (see a non-exhaustive list at the bottom), it is still somewhere in the order of 1 minute. This is a major constraint on more effective use of kubernetes, particularly for sidekiq (we cannot autoscale based on things like queue length, when the SLO for the queue is 10 seconds), but also doesn't exactly help our scaling of the web service fleet. Some other work is ongoing w.r.t. autoload/eagerload as well, but with no ETA.
There is an opportunity here for some fresh eyes and some out-of-the-box thinking (perhaps looking at possibilities/layers below Rails or even below Ruby)
Some of the previous work
- gitlab-org/gitlab#211875 (closed)
- gitlab-org/gitlab#215914 (closed)
- gitlab-org/gitlab#197345 (closed)
- gitlab-org/gitlab#197346 (closed)
For a short period, see also this Slack thread
teamScalability ~"Scalability::P4" boardplanning workflow-infraTriage