all containers need to share the same /dev/shm

[laijs]

all containers need to share the same /dev/shm, the same tmpfs mount with bindmount for sharing.
since all containers share the same ipc ns in the sandbox.

More investigation is needed.

ref: setupIpcDirs() in moby/daemon/container_operations_unix.go

[laijs]

moby/moby#12046
quote:

Man pages say /dev/shm, but my experience was that glibc starts
with/dev/shm and if not a tmpfs, scans /proceed/mounts for any tmpfs.

After quickly going through the man pages and the glibc code. So it is indeed!