Sysbox fails to honor tmpfs mounts over the container's /tmp on systemd-based containers

[ctalledo]

For container images that have systemd inside, sysbox automatically mounts tmpfs on the container's /tmp (to satisfy a systemd requirement). The tmpfs mount is hardcoded with an upper limit of 64mb.

In some cases, users may want that tmpfs mount to be larger. The way to do this is to have users explicitly mount tmpfs over the container's /tmp. For example:

docker run --runtime=sysbox-runc -it --rm --tmpfs /tmp:rw,noexec,nosuid,size=131072k nestybox/ubuntu-bionic-systemd-docker

This however does not currently work, as sysbox has a bug in which it's ignoring the tmpfs mount over /tmp.

Let's fix this.

[ctalledo]

Until this is fixed, one work-around is to do a tmpfs mount over the container's /tmp from inside the container itself. In other words, start the container and run the following command from inside of it:

mount -t tmpfs -o size=2048M tmpfs /tmp

[ctalledo]

Fixed via sysbox-runc PR 17.

Closing!