As I have no specific experience maintaining any of the CPython build slaves, I can't speak to any maintenance issues which these slaves have encountered. I would expect that they are as minimal as the issues I have encountered maintaining slaves for other projects, but perhaps this is wrong. I do recall that there were some win32 issues (discussed on this list, I think) quite a while back, but I think those were resolved. I haven't heard of any other issues since then.
Only partially. One old issue was that previous builds would not complete, keeping the executable files open, preventing further runs. Buildbot is supposed to kill a build, but only kills the parent process (as it is really difficult to kill the entire process tree (*)). We work around this by explicitly killing any stale Python processes at the beginning of a new build. The remaining issue is the popups; if a process still has a popup, you can't even terminate it properly. There are two kinds of popups: system-generated ones, and CRT-generated ones. For the CRT ones, we once had a way to turn them off, but I'm not sure whether that mechanism might have been removed. For the system messages, there is a way to turn them off in the parent process. David Bolen (IIRC) had developed a patch, but I think this patch only runs on his system(s). Regards, Martin (*) it may help if Buildbot would create a Win32 job object, and then use TerminateJobObject. Contributions are welcome.