Matt Bennett <Matt.Bennett@xxxxxxxxxxxxxxxxxxx> writes: > On Thu, 2020-07-02 at 21:10 +0200, Christian Brauner wrote: >> On Thu, Jul 02, 2020 at 08:17:38AM -0500, Eric W. Biederman wrote: >> > Matt Bennett <matt.bennett@xxxxxxxxxxxxxxxxxxx> writes: >> > >> > > Previously the connector functionality could only be used by processes running in the >> > > default network namespace. This meant that any process that uses the connector functionality >> > > could not operate correctly when run inside a container. This is a draft patch series that >> > > attempts to now allow this functionality outside of the default network namespace. >> > > >> > > I see this has been discussed previously [1], but am not sure how my changes relate to all >> > > of the topics discussed there and/or if there are any unintended side effects from my draft >> > > changes. >> > >> > Is there a piece of software that uses connector that you want to get >> > working in containers? > > We have an IPC system [1] where processes can register their socket > details (unix, tcp, tipc, ...) to a 'monitor' process. Processes can > then get notified when other processes they are interested in > start/stop their servers and use the registered details to connect to > them. Everything works unless a process crashes, in which case the > monitoring process never removes their details. Therefore the > monitoring process uses the connector functionality with > PROC_EVENT_EXIT to detect when a process crashes and removes the > details if it is a previously registered PID. > > This was working for us until we tried to run our system in a container. > >> > >> > I am curious what the motivation is because up until now there has been >> > nothing very interesting using this functionality. So it hasn't been >> > worth anyone's time to make the necessary changes to the code. >> >> Imho, we should just state once and for all that the proc connector will >> not be namespaced. This is such a corner-case thing and has been >> non-namespaced for such a long time without consistent push for it to be >> namespaced combined with the fact that this needs quite some code to >> make it work correctly that I fear we end up buying more bugs than we're >> selling features. And realistically, you and I will end up maintaining >> this and I feel this is not worth the time(?). Maybe I'm being too >> pessimistic though. >> > > Fair enough. I can certainly look for another way to detect process > crashes. Interestingly I found a patch set [2] on the mailing list > that attempts to solve the problem I wish to solve, but it doesn't > look like the patches were ever developed further. From reading the > discussion thread on that patch set it appears that I should be doing > some form of polling on the /proc files. Recently Christian Brauner implemented pidfd complete with a poll operation that reports when a process terminates. If you are willing to change your userspace code switching to pidfd should be all that you need. Eric _______________________________________________ Containers mailing list Containers@xxxxxxxxxxxxxxxxxxxxxxxxxx https://lists.linuxfoundation.org/mailman/listinfo/containers
