Christian Brauner <christian.brauner@xxxxxxxxxx> writes: > Hey everyone, > > I vanished for a little while to focus on this work here so sorry for > not being available by mail for a while. > > Since quite a long time we have issues with sharing mounts between > multiple unprivileged containers with different id mappings, sharing a > rootfs between multiple containers with different id mappings, and also > sharing regular directories and filesystems between users with different > uids and gids. The latter use-cases have become even more important with > the availability and adoption of systemd-homed (cf. [1]) to implement > portable home directories. Can you walk us through the motivating use case? As of this year's LPC I had the distinct impression that the primary use case for such a feature was due to the RLIMIT_NPROC problem where two containers with the same users still wanted different uid mappings to the disk because the users were conflicting with each other because of the per user rlimits. Fixing rlimits is straight forward to implement, and easier to manage for implementations and administrators. Reading up on systemd-homed it appears to be a way to have encrypted home directories. Those home directories can either be encrypted at the fs or at the block level. Those home directories appear to have the goal of being luggable between systems. If the systems in question don't have common administration of uids and gids after lugging your encrypted home directory to another system chowning the files is required. Is that the use case you are looking at removing the need for systemd-homed to avoid chowning after lugging encrypted home directories from one system to another? Why would it be desirable to avoid the chown? If the goal is to solve fragmented administration of uid assignment I suggest that it might be better to solve the administration problem so that all of the uids of interest get assigned the same way on all of the systems of interest. To the extent it is possible to solve the uid assignment problem that would seem to have fewer long term administrative problems. Eric
