From owner-cvs-all@FreeBSD.ORG Thu May 29 14:56:51 2008 Return-Path: Delivered-To: cvs-all@freebsd.org Received: from mx1.freebsd.org (mx1.freebsd.org [IPv6:2001:4f8:fff6::34]) by hub.freebsd.org (Postfix) with ESMTP id 3DF3D1065677; Thu, 29 May 2008 14:56:51 +0000 (UTC) (envelope-from rwatson@FreeBSD.org) Received: from cyrus.watson.org (cyrus.watson.org [209.31.154.42]) by mx1.freebsd.org (Postfix) with ESMTP id ECAAF8FC13; Thu, 29 May 2008 14:56:50 +0000 (UTC) (envelope-from rwatson@FreeBSD.org) Received: from fledge.watson.org (fledge.watson.org [209.31.154.41]) by cyrus.watson.org (Postfix) with ESMTP id 4521646C1F; Thu, 29 May 2008 10:56:50 -0400 (EDT) Date: Thu, 29 May 2008 15:56:50 +0100 (BST) From: Robert Watson X-X-Sender: robert@fledge.watson.org To: Michael Reifenberger In-Reply-To: <20080529145319.GC94385@gw.reifenberger.com> Message-ID: <20080529155422.T3678@fledge.watson.org> References: <200805261157.m4QBvnpF025029@repoman.freebsd.org> <20080526144831.K26343@fledge.watson.org> <20080526140735.GA35960@gw.reifenberger.com> <200805281309.49683.jhb@freebsd.org> <20080529140557.GA94385@gw.reifenberger.com> <20080529151233.I3678@fledge.watson.org> <20080529145319.GC94385@gw.reifenberger.com> MIME-Version: 1.0 Content-Type: TEXT/PLAIN; charset=US-ASCII; format=flowed Cc: cvs-src@freebsd.org, src-committers@freebsd.org, cvs-all@freebsd.org, John Baldwin Subject: Re: cvs commit: src/usr.sbin/jexec jexec.8 jexec.c X-BeenThere: cvs-all@freebsd.org X-Mailman-Version: 2.1.5 Precedence: list List-Id: CVS commit messages for the entire tree List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , X-List-Received-Date: Thu, 29 May 2008 14:56:51 -0000 On Thu, 29 May 2008, Michael Reifenberger wrote: > On Thu, May 29, 2008 at 03:14:20PM +0100, Robert Watson wrote: ... >> The other concept that might be of benefit is a "dead" jail vs. a "live" >> jail -- with TCP connections taking a while to run down, there can often be >> dangling jail references that don't garbage collect for a few minutes. >> Perhaps, where there is ambiguity, live jails (ones with referencing >> processes) should be preferred to dead ones. > > Thats something that the admin should take care for. How might they do that? Remember that any command that works only when the jail IP is "unambiguous" will become effectively non-deterministic as a result of un-garbage collected jails. So sometimes jexec -h foo will simply work, and sometimes return an error, depending on whether 2MSL has happened yet or not. I have to say that I really don't think that this addition is a good idea. Once unique, administratively-determined jail names are available, and if we add the idea of "dying" jails, then this may be useful. Otherwise, it seems like a conceptually inconsistent concept that fails to match the implementation -- i.e., one that will always work badly. Robert N M Watson Computer Laboratory University of Cambridge