[Podman] Re: mqueue msg_max in rootless container

Yes!!! --ipc host did it thanks a lot! Option with nsenter looks more preferrable to me, but as I understand I need first to start the container up, then run nsenter at host to change the mqueue settings and then somehow signal the container tht it can proceed with actual application. Is it possible to run nsenter during image build with buildah - I guess not? Best regards and thanks again!

On 20.05.2021 23:10, Giuseppe Scrivano wrote: > /proc/sys/fs/mqueue/msg_max is IPC namespaced but it is always owned by > root in the initial user namespace. A rootless container doesn't have > enough privileges to write to it. > > You can verify it with: > > $ podman run --rm fedora stat /proc/sys/fs/mqueue/msg_max > File: /proc/sys/fs/mqueue/msg_max > Size: 0 Blocks: 0 IO Block: 1024 regular empty file > Device: 7bh/123d Inode: 3634162 Links: 1 > Access: (0644/-rw-r--r--) Uid: (65534/ nobody) Gid: (65534/ nobody) > > So given the current limitation in the kernel, you have two possible > choices to workaround it: > > 1) run with --ipc host > 2) get some help from root in the host: > > $ sudo nsenter -i -t $CONTAINER_PID sh -c 'echo $NEW_MSG_MAX > /proc/sys/fs/mqueue/msg_max' > > Giuseppe > > > Michael Ivanov<ivans(a)isle.spb.ru> writes: > >> Yes it is 256: >> >> island:backend [master]> cat /proc/sys/fs/mqueue/msg_max >> 256 >> >> On 20.05.2021 21:00, Daniel Walsh wrote: >> >> On 5/20/21 08:29, Michael Ivanov wrote: >> >> Hallo! >> >> I'm trying to run my application in podman rootless container and I stumble >> on following problem: my program needs /proc/sys/fs/mqueue/msg_max to be at >> least 256, but in running container this value is just 10. When I try to >> specify this parameter while running the image (--sysctl 'fs.mqueue.msg_max=256') >> I get the following error: >> >> Error: open /proc/sys/fs/mqueue/msg_max: Permission denied: OCI permission denied >> >> and container is not created. >> >> My host where container is being run has this parameter set to 256. How can I >> expose current host setting for msg_max to my container? >> >> Best regards, >> >> When you login to your user account is is et to 256? >> >> $ cat /proc/sys/fs/mqueue/msg_max >> 10 >> _______________________________________________ >> Podman mailing list --podman(a)lists.podman.io >> To unsubscribe send an email topodman-leave(a)lists.podman.io > _______________________________________________ > Podman mailing list --podman(a)lists.podman.io > To unsubscribe send an email topodman-leave(a)lists.podman.io -- \ / | | (OvO) | Михаил Иванов | (^^^) | Тел.: +7(911) 223-1300 | \^/ | E-mail:ivans@isle.spb.ru | ^ ^ | |