On Wed, Mar 8, 2017 at 2:56 AM, Prabhunath G <gprabhunath@gmail.com> wrote:

Hi All,

Binding / folder onto someother folder say /opt/lxc is not working but otherway round is working. Can I get some help on this.

The following code snippet is executed after cloning After executing the following code snippet the contents of / is visible in /opt/lxc ret = mount("/", "/opt/lxc", NULL, MS_BIND, NULL); if (ret) { perror("mount bind / on /opt/lxc"); exit(1); }

But after executing the following code snippet the contents of /opt/lxc is not visible in / ret = mount("/opt/lxc", "/", NULL, MS_BIND, NULL); if (ret) { perror("mount bind /opt/lxc on /"); exit(1); }

The code is executing successfully, but the result is not as expected.

It's a little curious that the bind succeeds -- if you try "mount --move /opt/lxc /" you would get an error. I'd guess there's some use case for a / bind mount like that though offhand I don't see it. But bind mounts aren't substitutes for a chroot(2) call, which I think is what you'll need for your application. Bind mounts could still be useful in setting up the running chroot environment: mount --bind /proc /opt/lxc/proc, etc. -- Jim