Likewise for me. My plans for the next weeks are to experiment with the Shepherd on Android, mixing in magiskinit as the first init program. I got guix running on Android, the next step will be also shepherd. I'll also watch the recording again, and some of the others from the same devroom, as I missed some talks when I switched to the robotics devroom.
Alex (they/them) On Sat, 2025-02-08 at 19:00 +0100, Gábor Boskovits wrote: > Hello, > > Ludo's FOSDEM talk inspired me to share some thoughts that I > encountered during my time at my previous position where we designed > an init system. > > This might be better targeted specifically for shepherd, in this case > please redirect and let me know. > > The fist things are the specialities of the pid 1 processes: > - they own the pid namespace where they are pid 1 (this works > automatically, there is nothing to do here) > - they do not have default signal handling (this means that when > running as pid1 you might want to have a default set of signal > handlers installed) > - the orphaned processes from the pid namespace get automatically > reparented to them (on linux there is a concept called a subreaper > process that allows to delegate this responsibility downwards, having > the orphaned processes reparented to the subreapers, to be able to > manage process subtrees without the need to spin up a new nested pid > namespace, we might want to provide configuration to enable the > subreaper behavior) > > Also, now pid 1 exist on all pid namespace of the pid namespace > hierarchy, and also from the outer nesting levels these are also > visible under a different pid. We might take a look how shepherd > interacts with these. > > On the process management front a quite important new API is > available in newer linux kernels, called pidfd, which allows to have > a file descriptor interface to a process, making signaling and > waiting for processes much less error prone. > > Tbh. I did not have time to do my homework yet on the shepherd > internals, so it might well be that some things from the above are > already there, maybe someone can advise on the status and if there is > some interest in any of these aspects. > > Regards, > g_bor > >
