Message-ID: <43E88823.3060203@sw.ru>
Date: Tue, 07 Feb 2006 14:44:35 +0300
From: Kirill Korotaev <dev@sw.ru>
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To: Cedric Le Goater <clg@fr.ibm.com>
CC: Alexey Kuznetsov <kuznet@ms2.inr.ac.ru>,
       "Serge E. Hallyn" <serue@us.ibm.com>, Dave Hansen <haveblue@us.ibm.com>,
       Kirill Korotaev <dev@openvz.org>, arjan@infradead.org,
       frankeh@watson.ibm.com, mrmacman_g4@mac.com, alan@lxorguk.ukuu.org.uk,
       Linux Kernel Mailing List <linux-kernel@vger.kernel.org>,
       devel@openvz.org
Subject: Re: [RFC][PATCH 5/7] VPIDs: vpid/pid conversion in VPID enabled case
References: <43E22B2D.1040607@openvz.org> <43E23398.7090608@openvz.org> <1138899951.29030.30.camel@localhost.localdomain> <20060203105202.GA21819@ms2.inr.ac.ru> <43E35105.3080208@fr.ibm.com> <20060203140229.GA16266@ms2.inr.ac.ru> <43E38D40.3030003@fr.ibm.com> <20060206094843.GA6013@ms2.inr.ac.ru> <20060206145104.GB11887@sergelap.austin.ibm.com> <20060206155101.GA22522@ms2.inr.ac.ru> <43E86C73.2070608@fr.ibm.com>
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>>The question was not about openvz, it was about (container,pid) approach.
>>How are you going to reap chidren without a child reaper inside container?
>>If you reparent all the children to a single init in root container,
>>what does wait() return? In openvz it returns global pid and child is buried
>>in peace. If you do not have global pid, you cannot just return private pid.
> 
> I think the "child reaper" question is not related to the (container,pid)
> approach or the vpid approach. This is another question on who is the
> parent of a container and how does it behaves.
it is related. How reaps the last process in container when it dies?
what does waitpid() return?

> We have choosen to first follow a simple "path", complete pid isolation
> being the main constraint : a container is created by exec'ing a process in
> it.
Why to exec? It was asked already some times...

> That first process is detached from its parent processes and becomes
> child of init (already running), session leader, and process group leader.
> We could eventually add a daemon to act as a init process for the container.
See my prev question. Who reaps your init itself?

> Now, there are other ways of seeing a container parenthood, openvz, eric,
> vserver, etc. We should agree on this or find a way to have different model
> cohabitate.

Kirill

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