I've been digging into groups support, there's a few things that are easy fixes but a few things become problematic so I'd like to discuss.
First the code makes certain options dictated that can be placed in the yarn-site.xml - this should be done to remove code and provide flexibility. That's easy. The second involves the cgroup hierarchy and the cgroup mount point. Here the code attempts to create a hierarchy in $CGROUP_DIR/mesos/$TASK_ID. This is problematic as mesos will not unmount the hierarchy when the task finished (in this case the node manager), it is also therefore unable to unmount it's own task hierarchy (This also creates the need to chmod a number of directories as a superuser). This leads to issues. An alternative approach would be to use the container-executor program (already suid w/ yarn's group) to create the hierarchy as $CGROUP_DIR/frameworkname if it doesn't exist, this may open another can of worms as I haven't tested fully. Any thoughts or suggestions would be appreciated. Darin
