[CRIU] How to save custom container properties?

[Pavel Emelyanov]

On 02/16/2016 10:41 AM, Cyrill Gorcunov wrote:
> On Tue, Feb 16, 2016 at 10:26:49AM +0300, Pavel Emelyanov wrote:
>> On 02/16/2016 10:18 AM, Pavel Tikhomirov wrote:
>>> We have virtualized core_pattern in VZ7 CT, which was needed by QA to 
>>> catch coredumps in CT. The question is: How to c/r it with CRIU? It is 
>>> not mainstream behaviour to have separate kernel.core_pattern sysctl in 
>>> CT, so my first thought was in action scripts. But in that case, do we 
>>> have some interface to save data collected by action script to some 
>>> special image?
>>
>> No we don't. You can pick any format, but for uniformity I'd recommend
>> declaring .proto file with ovz-specific info and save it in ovz.img
>> file the way criu does.
>>
>> I think we can introduce helper routine(s) in lib/ for such cases.
> 
> Letme think a bit. I vote for vz.img for sure but I would love to
> escape changing criu code too much because it gonna be hard to
> support both versions (vanilla and pcs7 one).
> 
> Not sure what you mean by helpers in lib. Mind to share?

Sure. The vz-specific stuff would be dumped in one of action script (post-dump?)
and to write the data in protobuf format it would be handy to have some support
from criu.

The same support would be useful for plugin writers, if I'm not mistaken some
of our tests (ext-mount) already do such tricks.

-- Pavel