[lxc-users] Set specific mount options for the ROOTFS

[Olivier BONHOMME]

On Mon, Jun 20, 2016 at 10:49:50AM -0500, Serge E. Hallyn wrote:
> Can you try actually writing to a file in the rootfs?  Since your
> rootfs is a bind mount, there is no separate filesystem to make
> ro.  Rather, the bind mount should be made a ro mount without
> changing the fs options.  You create a separate rootfs (Look at
> the -B option) if you want more separation.

For the ro part I guess it is due to the fact that a mount bind can't be done in RO mode directly ?

So I followed your advice, and used the -B option which I didn't detect during my doc reading.

I tried creating a rootfs using a loop device and it worked perfectly. I had issues with pivot root but I could bypass them using lxc.pivotdir option.

I have now a ro rootfs.Thanks for your advice. I guess maybe it should be nice to precise in the documentation that lxc.rootfs.options is not compliant with the 'dir' backend.

On CentOS, I couldn't create the rootfs using ext2/3/4 fs. I had to use
XFS which was the only that worked.

Do you have an idea about the root cause ?

Regards,
Olivier Bonhomme