to elaborate on the "resource busy" issue... you need to remove/kill the running processes from the cgroup in order to remove the folder.
view the tasks with:
$ cat /cgroup/ubuntu-lucid/tasks <all the pids assigned to this cgroup>
$ kill -15 <all the pids assigned to above cgroup>
most processes should die, unless it was pid one in the container, then it will need a kill -9. after that you can:
$ rmdir /cgroup/ubuntu-lucid
so long as there are no more nested directories under /cgroup/ubuntu-lucid.
to elaborate on the "resource busy" issue... you need to remove/kill the running processes from the cgroup in order to remove the folder.
view the tasks with:
$ cat /cgroup/ ubuntu- lucid/tasks
<all the pids assigned to this cgroup>
$ kill -15 <all the pids assigned to above cgroup>
most processes should die, unless it was pid one in the container, then it will need a kill -9. after that you can:
$ rmdir /cgroup/ ubuntu- lucid
so long as there are no more nested directories under /cgroup/ ubuntu- lucid.