[CRIU] Dumping tmux session with a client connected

[Cyrill Gorcunov]

On Mon, Apr 13, 2015 at 01:52:06PM -0700, Allan Cecil wrote:
> 
> Now only the tmux server remains as the client has disconnected; in this state, dumping 16449 will succeed because there
> is no client attached.  Now, type tmux attach in the other terminal and a new process starts:
> 
> 16605 pts/3    S+     0:00  |           \_ tmux attach
> 16607 pts/2    S+     0:00              \_ grep --color=auto tmux
> 16449 ?        Ss     0:12 tmux
> 
> Dumping 16449 will now fail with the error in the logs.  The goal is to be able to dump while a client is attached, preferably with
> the --leave-running flag set, and later restore the server and allow a client to connect to it (this would be handled automatically
> by my python script).  Since dumping a tmux session with a client attached always fails, I'm pursuing a method where I launch two
> tmux instances and completely detach all clients from the "inner" session so the dump succeeds, but this is less preferable because
> it will cause a lot of noise on the terminal compared to the existing KVM method.  Having said all that, it might be not worthwhile
> to try to make this use case work. :)

I see, thanks for info about tmux. Actually if you wanna c/r tmux server only with clients connected
I fear there is no simple workaround as far as I see. The external stream socket is a huge problem
(even imagine we "allow" to checkpoint server with this socket peer, we won't be able to restore it
 because the client still keeps old reference to a former socket peer). Dunno, maybe Pavel has some
ideas?