[lxc-devel] mount ro in guest change host filesystem to ro

[Michael Tokarev]

On 02.09.2011 00:46, Daniel Lezcano wrote:
> On 09/01/2011 09:30 PM, Nico wrote:
>> Hi,
>>
>> I just wanted to give it a try again with lxc after one year,
>> this is so bad same bugs are always here :
>>
>> * you can do a "mount -o romount,ro /" inside container (reported
>> since first times ... :( ),
>> and host filesystem is remounted ro !!
> 
> Argh ! I still don't understand how that can happen with a CLONE_NEWNS
> and a pivot_root.
> Do you have particular mount options on your host's rootfs ?

In order for guest remount to NOT influence host mount, you have to
give -o bind option to mount inside guest.  If you don't specify
MS_BIND with MS_REMOUNT, the remount applies to _host_ mountpoint,
not guest.

This has been discussed several times on irc.

/mjt