From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1761653Ab2FEJjg (ORCPT ); Tue, 5 Jun 2012 05:39:36 -0400 Received: from mx2.parallels.com ([64.131.90.16]:44572 "EHLO mx2.parallels.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1761546Ab2FEJje (ORCPT ); Tue, 5 Jun 2012 05:39:34 -0400 Message-ID: <4FCDD346.9090008@parallels.com> Date: Tue, 5 Jun 2012 13:37:10 +0400 From: Glauber Costa User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:12.0) Gecko/20120430 Thunderbird/12.0.1 MIME-Version: 1.0 To: Daniel Lezcano CC: , , , , Serge Hallyn , Oleg Nesterov , Michael Kerrisk , "Eric W. Biederman" , Tejun Heo Subject: Re: [PATCH] allow a task to join a pid namespace References: <1338816828-25312-1-git-send-email-glommer@parallels.com> <4FCDD315.502@free.fr> In-Reply-To: <4FCDD315.502@free.fr> Content-Type: text/plain; charset="ISO-8859-1"; format=flowed Content-Transfer-Encoding: 7bit Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On 06/05/2012 01:36 PM, Daniel Lezcano wrote: > On 06/04/2012 03:33 PM, Glauber Costa wrote: >> Currently, it is possible for a process to join existing >> net, uts and ipc namespaces. This patch allows a process to join an >> existing pid namespace as well. >> >> For that to remain sane, some restrictions are made in the calling process: >> >> * It needs to be in the parent namespace of the namespace it wants to jump to >> * It needs to sit in its own session and group as a leader. >> >> The rationale for that, is that people want to trigger actions in a Container >> from the outside. For instance, mainstream linux recently gained the ability >> to safely reboot a container. It would be desirable, however, that this >> action is triggered from an admin in the outside world, very much like a >> power switch in a physical box. >> >> This would also allow us to connect a console to the container, provide a >> repair mode for setups without networking (or with a broken one), etc. > > Hi Glauber, > > I am in favor of this patch but I think the pidns support won't be > complete and some corner-cases are not handled. > > May be you can look at Eric's patchset [1] where, IMO, everything is > taken into account. Some of the patches may be already upstream. > > Thanks > -- Daniel I don't remember seeing such patchset in the mailing lists, but that might be my fault, due to traffic... I'll take a look. If it does what I need, I can just drop this. Thanks