[CRIU] Re: Issues of using CRtools

[Pavel Emelyanov]

On 10/10/2012 04:20 PM, Shinkevich Andrey wrote:
> Dear Pavel! Thank you for your efforts in developping CRtools!
> E-mail is the only way I found to contact you.

Please, keep the mailing list in Cc, other people can also help.

> I am new in Linux Kernel and trying to test CRtools to see how it works.
> But I've encountered some issues in running CRtools and ask you for favor to assist me in
> resolving them. - I run CRtools 2.0 on Ubuntu i86-64 VirtualBox - The Linux kernel has been
> updated and 'sudo crtools check' ends with the message "Looks Good." - Running CRtools without
> 'sudo' results in "Permission denied" message 

This is kernel requirement. Lots of the APIs we use require root prio.

> - If I run 'gcalctool &' command from 
> Terminal(tty), and then 'sudo crtools dump -t 7472 -c' the error message appears: "tty.c:156
> Found slave peer index 0 without correspond master peer" 

That's because you dump only one end of a PTY. This case is not supported yet, but
we're working on this.

> - If I run the Calculator from Ubuntu
> GUI and then run the command 'sudo crtools dump -t 7494 -c', the image files are generated and 
> the process 7494 is killed anyway.

Read the help carefully. By default crtools kills the processes it dumped, but there's a way
to override this behavior.

> - Then the following command 'sudo crtools restore -t 7494' results in forced user logging off

This can be because X apps may use SysVIPC resources you didn't dump and at the restore stage
X server may go nuts and act strange. Another thing is that dumping X apps is tricky, since
part of application state resides on the Xserver side and crtools currently do not handle this.

If you are familiar with how X works and can participate to the project this will be appreciated.

> - Additional option '-n uts, ipc' does not help

Absolutely.

> 1. What is wrong with it and how can I run the CRtools correctly? 

The usecases we've recently worked on include 3 cases

a) daemons
b) shell tools (but there are limitations with PTYs and sids. Effectively you can
   for now only succeed when using the screen app, but it's improving)
c) containers

Dumping X apps was not taken into account yet. The demo you might have seen on Yandex
conference dumped a VNC X _server_, which is not the same as dumping X client (i.e. app).

> 2. Where and how can I download the ZDTM test suite?

It's in the sources in the test/zdtm directory. Plus reading http://criu.org/ZDTM_Test_Suite
might help.

> Thank you! You may respond in Russian if you like. Best regards, Andrey

Thanks,
Pavel