id summary reporter owner description type status priority milestone component resolution keywords cc fix_version see_also 775 Cluster logouts are slow because of schroot stupidity broder "/etc/schroot/setup/15killprocs in schroot is responsible for making sure that no processes are still running in a chroot when that chroot is torn down. It does this by looping over the processes still running in the chroot. For each process, it sends a SIGTERM, then immediately checks to see if the process is still running. If not, it then sleeps for 1 second before trying again. The problem with this approach is that most programs try to handle SIGTERM gracefully, and therefore do not exit out immediately. When geofft instrumented the logout process, it looked like there were about 15 such processes, causing 15 seconds worth of sleep before the logout would continue. This is '''the''' major cause of logout slowness on cluster machines. When we used LVM snapshots for the login chroots, we had code to use fuser(1) to first SIGTERM and then eventually SIGKILL all processes running within the chroots, but we removed it from snapshot-run when we switched to aufs chroots. Bringing that code back and adding it before snapshot-run calls schroot -e would eliminate this issue." enhancement closed normal Precise Release login chroot fixed