From mboxrd@z Thu Jan 1 00:00:00 1970 From: ebiederm-aS9lmoZGLiVWk0Htik3J/w@public.gmane.org (Eric W. Biederman) Subject: Re: [RFC PATCH net-next v2 0/5] netns: allow to identify peer netns Date: Fri, 26 Sep 2014 12:34:16 -0700 Message-ID: <87mw9myy4n.fsf@x220.int.ebiederm.org> References: <1411478430-4989-1-git-send-email-nicolas.dichtel@6wind.com> <54228D87.3070309@6wind.com> <5422F0F4.6000709@6wind.com> <5423D80B.9060500@6wind.com> <54256CCB.4000709@6wind.com> <5425BB3E.10700@gmail.com> Mime-Version: 1.0 Content-Type: text/plain Return-path: In-Reply-To: <5425BB3E.10700-Re5JQEeQqe8AvxtiuMwx3w@public.gmane.org> (David Ahern's message of "Fri, 26 Sep 2014 13:15:10 -0600") Sender: linux-api-owner-u79uwXL29TY76Z2rM5mHXA@public.gmane.org To: David Ahern Cc: nicolas.dichtel-pdR9zngts4EAvxtiuMwx3w@public.gmane.org, Cong Wang , netdev , containers-cunTk1MwBs9QetFLy7KEm3xJsTq8ys+cHZ5vskTnxNA@public.gmane.org, "linux-kernel@vger.kernel.org" , linux-api-u79uwXL29TY76Z2rM5mHXA@public.gmane.org, David Miller , Stephen Hemminger , Andrew Morton , Andy Lutomirski List-Id: linux-api@vger.kernel.org David Ahern writes: > On 9/26/14, 7:40 AM, Nicolas Dichtel wrote: >>> >>> >>> No, I don't want to monitor anything. Even if I wanted, I would just >>> start one >>> daemon in each netns instead of one for all. >> Ok you don't want, but some other people (not only me) want it! And >> having one >> daemon per netns does not scale: there are scenarii with thousand netns >> which >> are dynamically created and deleted. > > An example of the scaling problem using quagga (old but still seems to be a > relevant data point): > > > https://lists.quagga.net/pipermail/quagga-users/2010-February/011351.html > > "2k VRFs that would be 2.6G" > > And that does not include the overhead of each namespace -- roughly > 200kB/namespace on one kernel I checked (v3.10). So that's a ballpark of 3G of > memory. Resetting the conversation just a little bit. When I wrote the "ip netns" support I never expected that all applications would want to run in a specific network namespace. All that is needed is one socket per network namespace. Furthermore one socket or one procesess per network namespaces is completely orthogonal to the patches presented. I do not see a identifying where the far end of a veth pair or similar set of networking objects as anything that even closely resembles a path to a using only a single socket. So I think this whole subthread is quite silly and grossly off track. Eric