> I think you can already build Docker images via Docker within travis CI, [...] The nice think about plash is that you don't have to worry about "official" su

> I think you can already build Docker images via Docker within travis CI, [...] The nice think about plash is that you don't have to worry about "official" support. > [...] due to /sys being read-only. Dammit, no, so yeah, apparently unfortunately for regular docker containers (not privileged ones) you need to disable unsharing in plash (export PLASH_NO_UNSHARE=1). In that case the only requirements are chroot, a rudimentary mount binary and overlay OR unionfs-fuse and root access. So it should even run in BSD/Minix/macOS and stuff like that, BUT the mountpoints will not get cleaned up. For an instance running for a while that would be a problem, for a temporary docker container not.