[lxc-users] Setting lxc.pivotdir leaves mounted host "/" rw in container?

[steve at linuxsuite.org]

 Howdy!

         I am trying to make an lxc container with readonly root "/"

         I bind mount a "common" rootfs and make it readonly to use as a
readonly container root file system.

mount --bind /srv/common/ /srv/test/
mount -o remount,ro /srv/test

lxc.rootfs = /srv/test  ( in container config)

              lxc-start fails because /usr is readonly and /usr/lib64/lxc
is needed to be rw.

lxc-start: utils.c: mkdir_p: 202 Read-only file system - failed to create
directory '/usr/lib64/lxc/rootfs/lx
c_putold'

           So, I set lxc.pivotdir in container config ( I have a rw /var
in the container )

lxc.pivotdir = /var/mnt

         And it boots perfectly and I have a readonly "/", Yeay!!   but
then I notice
that the entire host filesystem is mounted read/write in the container
under /var/mnt...

      Why does this mount not go away? Ideas about what I have to do??

      lxc 1.0.8 on centos6.7

       thanx - steve