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

[steve at linuxsuite.org]

 Howdy!

          I am trying to make  lxc containers  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, I guess..

 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... tried both building from source tarball
from linuxcontainers.org
and EPEL package. Same thing

       mounted filesystems in the container

     ******* boot with default pivot
 Filesystem     1K-blocks    Used Available Use% Mounted on
rootfs          20027260 2889036  16114224  16%        /
/dev/md0p4      20027260 2889036  16114224  16% /
devtmpfs         4014480     192   4014288   1%            /dev
tmpfs            4026484       0   4026484   0%                  /dev/shm


        ****  after setting lxc.pivot = /var/mnt
Filesystem     1K-blocks    Used Available Use% Mounted on
rootfs          20027260 2889184  16114076  16%        /
/dev/md0p4      20027260 2889184  16114076  16% /var/mnt
devtmpfs         4014480     192   4014288   1%            /var/mnt/dev
devtmpfs         4014480     192   4014288   1%            /var/mnt/dev
tmpfs            4026484       0   4026484   0%                 
/var/mnt/dev/shm
/dev/md0p4      20027260 2889184  16114076  16% /var/mnt/srv/test
/dev/md0p4      20027260 2889184  16114076  16% /
devtmpfs         4014480     192   4014288   1%            /dev
tmpfs            4026484       0   4026484   0%                  /dev/shm

        thanx - steve