[CRIU] [PATCH 0/3 v3] crtools: close a signal descriptor after passing a preparation stage

[Adrian Reber]

On Wed, Jan 11, 2017 at 12:28:08PM -0800, Andrei Vagin wrote:
> On Wed, Jan 11, 2017 at 08:36:20AM +0100, Adrian Reber wrote:
> > On Wed, Jan 11, 2017 at 12:21:42AM +0300, Andrei Vagin wrote:
> > > This patch adds the --siganl-fd FD option to specify a file descriptor.
> > > CRIU will write '\0' to this descriptor and close it after passing
> > > a preparation stage.
> > > 
> > > It is alternative way to demonizing a criu process after a preparation
> > > stage. It's imposiable to get exit code, if a process has daemonized.
> > > 
> > > The introduced way allows to wait a preparation stage and to get an exit
> > > code. It can be easy used from shell and other script languages.
> > 
> > As I am currently looking at runc and criu lazy-pages I want to make
> > sure I understand this correctly. It sounds like I could pass a FD to
> > criu and start in in lazy-page mode. Once criu reaches the point where I
> > can make TCP connections to request lazy pages this FD will be closed,
> > right?
> 
> Yes

Perfect! I was able to use your patch to integrate post-copy migration
into runc. As long as forked processes are not possible it is still
limited, but at least it works for single process containers! Great!

		Adrian