[CRIU] [RFC][PATCH 0/3] Proposal for native (w/o plugins) support for external bind mounts v2

[Pavel Emelyanov]

On 06/06/2014 12:20 PM, Andrew Vagin wrote:
> Looks good to me.
> 
> I would like to have a test for this option.

In zdtm/ suite? It's not ready for anything that sits outside
of the processes it dumps :)

> On Thu, Jun 05, 2014 at 07:10:43PM +0400, Pavel Emelyanov wrote:
>> So, the 1st attempt with modifying original mount points roots is
>> not working since the paths we see in /proc and dump are relative
>> to the FS's root, not relative to global (well, CRIU's) root.
>>
>> That said, we can try to go another route and here it is.
>>
>> On dump we use one or more --ext-mount option with A=B arguments.
>> A denotes a mountpoint (as seen from the target mount namespace)
>> criu dumps and B is the string that will be written into the
>> image file instead of the mountpoint's root. E.g. if we have a
>> /foo/bar bind mounted into container under /x name, then the
>> --ext-mount /x=foobar option will tell criu, that /x is a mount
>> point with external source and it should write "foobar" into image
>> instead of the path read from /proc.
>>
>> On restore we use the same --ext-mount option(s) with similar
>> A=B arguments, but this time criu treats A as string from the
>> image's root field (foobar in the example above) and B as the
>> path in criu's mount namespace the should be bind mounted into
>> the mountpoint.
>>
>> For example, let's again imagine we have /foo/bar bind mounted
>> into container under /x name and /foo/bar is inaccessible from
>> this container.
>>
>> On dump we say --ext-mount /x=foobar and mountpoints.img will
>> contain a mountpoint with root=foobar and mountpoint=/x. On restore
>> we use --ext-mount foobar=/foo2/bar option. This will result the
>> /foo2/bar from criu's namespace get bind-mounted to /x inside the
>> container we restore.
>>
>>
>> Thanks,
>> Pavel
>> _______________________________________________
>> CRIU mailing list
>> CRIU at openvz.org
>> https://lists.openvz.org/mailman/listinfo/criu
> .
>