From mboxrd@z Thu Jan 1 00:00:00 1970 From: sukadev-r/Jw6+rmf7HQT0dZR+AlfA@public.gmane.org Subject: Re: [DRAFT] Container mini-summit notes v0.01 Date: Wed, 17 Oct 2007 17:52:16 -0700 Message-ID: <20071018005216.GA916@us.ibm.com> References: <6599ad830709050700y278d653eu371375c2fc107ef@mail.gmail.com> <20070905143808.GG1403@sergelap.austin.ibm.com> <46DF35DA.1090102@cs.columbia.edu> <20070905235828.GA32475@sergelap.austin.ibm.com> <46DFBE60.6030404@fr.ibm.com> <20070906153243.GA15436@sergelap.austin.ibm.com> <20070910141834.GA5866@sergelap.austin.ibm.com> <46FABD9D.50407@cs.columbia.edu> Mime-Version: 1.0 Content-Type: text/plain; charset=us-ascii Return-path: Content-Disposition: inline In-Reply-To: <46FABD9D.50407-eQaUEPhvms7ENvBUuze7eA@public.gmane.org> List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Sender: containers-bounces-cunTk1MwBs9QetFLy7KEm3xJsTq8ys+cHZ5vskTnxNA@public.gmane.org Errors-To: containers-bounces-cunTk1MwBs9QetFLy7KEm3xJsTq8ys+cHZ5vskTnxNA@public.gmane.org To: Oren Laadan Cc: Kir Kolyshkin , Masahiko Takahashi , "Eric W. Biederman" , Linux Containers , Paul Menage , Pavel Emelianov List-Id: containers.vger.kernel.org Oren Laadan [orenl-eQaUEPhvms7ENvBUuze7eA@public.gmane.org] wrote: | | (sorry from the delay, been away :) | | Eric W. Biederman wrote: | > "Serge E. Hallyn" writes: | > | >> Sorry, I was focusing on the virtual server needs. | >> | >> devpts is it's own fs so I was fully expecting to make it mountable | >> multiple times so a container can have it's own /dev/pts/0. So what | >> other virtual devices would we want to be able to rec-reate for a | >> migrated application? (I wonder (a) what gregkh will say about having | >> a device namespace, and (b) what the sysfs implications will be) | > | > Depends. There are things like the loop device that could be interesting. | > There may be some others. I haven't looked at it enough detail to get | > beyond the fact that in some sense it isn't just limited to pts devices. | > | > A multimount devpts is interesting though. | | Devices I had to deal with (in zap) so far - to be able to ckpt/restart | (and migrate) a desktop session: | | * /dev/rtc (e.g. for mplayer) | | * /dev/dsp | | * /dev/random ? (to isolate entropy pools ?) | | * virtual consoles - e.g. in zap, an X server that uses a virtual device | runs inside a pod/container/VE (and X per-se requires a virtual console) | | * virtual terminals - e.g. in zap we allow access to a pod from the host | without a need to run 'sshd' inside and setup a network in the pod. (Then | with a suitable utility and network access to the host, this also allows | sort of remote (a-la serial) console access). | >From inside the pod it looks like /dev/tty{1,2,..}, so one can run 'getty' | processes inside the pod. From the outside (for the admin, e.g.) it is an | extended /dev/tty that has an extra ioctl to multiplex access, so the | admin (program) can ask to be connected to tty X of pod Y, and it will | connect to that console (like connecting via serial line). This sounds really interesting. Were these devices part of a complete device namespace ? IOW, does say /dev/tty2 in each pods have the same major/minor number (4,2) ? Does each '/dev/tty2' have a separate entry in sysfs ? | The main advantage is that as a virtual device it can be migrated (with | its buffers, if not empty, as they reside inside the pod) so upon restart | they go with the 'getty' processes that use them. The (old) admin will | see the line dropped, and the (new) admin after the migration can connect | at the new machine. | | Oren. | | | _______________________________________________ | Containers mailing list | Containers-cunTk1MwBs9QetFLy7KEm3xJsTq8ys+cHZ5vskTnxNA@public.gmane.org | https://lists.linux-foundation.org/mailman/listinfo/containers