From mboxrd@z Thu Jan 1 00:00:00 1970 From: ebiederm-aS9lmoZGLiVWk0Htik3J/w@public.gmane.org (Eric W. Biederman) Subject: Re: [RFC][PATCH 0/9] Make containers kernel objects Date: Tue, 23 May 2017 10:17:26 -0500 Message-ID: <87bmqjmwl5.fsf@xmission.com> References: <87zie3mxkc.fsf@xmission.com> <149547014649.10599.12025037906646164347.stgit@warthog.procyon.org.uk> <1495472039.2757.19.camel@HansenPartnership.com> <2446.1495551216@warthog.procyon.org.uk> <2961.1495552481@warthog.procyon.org.uk> Mime-Version: 1.0 Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: 7bit Return-path: In-Reply-To: <2961.1495552481-S6HVgzuS8uM4Awkfq6JHfwNdhmdF6hFW@public.gmane.org> (David Howells's message of "Tue, 23 May 2017 16:14:41 +0100") List-Id: 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: David Howells Cc: mszeredi-H+wXaHxf7aLQT0dZR+AlfA@public.gmane.org, linux-nfs-u79uwXL29TY76Z2rM5mHXA@public.gmane.org, jlayton-H+wXaHxf7aLQT0dZR+AlfA@public.gmane.org, Linux Containers , linux-kernel-u79uwXL29TY76Z2rM5mHXA@public.gmane.org, James Bottomley , viro-RmSDqhL/yNMiFSDQTTA3OLVCufUGDwFn@public.gmane.org, cgroups-u79uwXL29TY76Z2rM5mHXA@public.gmane.org, linux-fsdevel-u79uwXL29TY76Z2rM5mHXA@public.gmane.org, trondmy-7I+n7zu2hftEKMMhf/gKZA@public.gmane.org David Howells writes: > Eric W. Biederman wrote: > >> > As an example, I could set up a client machine with two ethernet ports, >> > set up two DNS+NFS servers, each of which think they're called "foo.bar" >> > and attach each server to a different port on the client machine. Then I >> > could create a pair of containers on the client machine and route the >> > network in each container to a different port. Now there's a problem >> > because the names of the cached DNS records for each port overlap. >> >> Please look at ip netns add. > > warthog>man ip | grep setns > warthog1> Not setns netns >> It does solve this in userspace rather simply. > > Ummm... How? The kernel DNS resolver is not namespace aware. But it works fine if called in the proper context and we have a defacto standard for where to put all of the files (the tricky part) if you are dealing with multiple network namespaces simultaneously. Eric