[RFC] Refactoring OpenWrt's build infra

[Thibaut]

Hi,

Following an earlier conversation on IRC with Petr, I’m willing to work on refactoring our buildbot setup as follows:

- single master for each stage (images and packages)
- latent workers attached to either master, thus able to build opportunistically from either master or release branches as needed / as work becomes available

The main upside is that all buildslaves could be pooled, improving overall throughput and reducing wasted « idle time », thus lowering build times and operating costs.

Petr also suggested that extra release workers could be spawned at will (through e.g. cloud VMs) when a new release is to be tagged; tagged release could be scheduled only to release workers: this would still work within this « single master » build scheme.

NB: I’m aware of the potential performance penalty of having buildslaves randomly switching between branches, so I would try to come up with a reasonably smart solution to this issue if it doesn’t conflict with the main goals.

Before I set on to revamp the system accordingly I want to ask if this proposal seems like a Good Idea™ :)

Comments welcome,
T.