Error setting fs.mqueue.msg_max in LXC container

Hallo! I need to set fs.mqueue.msg_max in container running under LXC compiled from master branch (reported version 3.1.0-devel). I tried to do it manually with systctl -p in container and it failed with “Read-only file system” error. I set the parameter at host to needed value (256) but when I restart the container it is still 10 inside. I added lxc.sysctl.fs.mqueue.msg_max = 256 to container config file but it will not even start, with same read-only fs error. I’m starting container as root under centos 7.6.1810. Certain other sysctl parameters seem to be properly propagated from host (at least this is the case for /proc/sys/kernel/core_pattern).
In which direction to dig?


I managed to get this working by adding following line to container config file:

lxc.mount.entry = /proc/sys/fs/mqueue proc/sys/fs/mqueue rw,none bind,optional 0 0

Is this expected way?
Can this somehow be made a default for all containers?