Subject: Re: [vserver] Understanding localhost
From: "John A. Sullivan III" <jsullivan@opensourcedevel.com>
Date: Fri, 01 May 2009 10:40:33 -0400

On Fri, 2009-05-01 at 22:03 +0800, Jeff Jansen wrote:
> "John A. Sullivan III" <jsullivan@opensourcedevel.com> wrote on 2009-May-01:
> > Am I correct to understand that, unlike earlier version, the default
> > kernel compilation makes it safe to use 127.0.0.1 on a guest? That is,
> > each one is uniquely mapped and does not interfere with the host
> > listening in 127.0.0.1? We can thus set our /etc/hosts files to use:
> > 127.0.0.1 localhost localhost.localdomain etc . . .?
> > 
> > However, is it also true that daemon bindings to localhost will still be
> > made to the address in /etc/vservers//interfaces/0 and will not
> > include 127.0.0.1 unless explicitly bound?
> 
> We don't see this, John.  It works like expected for us.
> 
> We have
> 
> 127.0.0.1	localhost.localdomain	localhost
> 
> in /etc/hosts and if a process is bound to 127.0.0.1 (or localhost) then that's
> what it binds to.  And if it's bound to * then you can reach it on localhost as
> well.
> 
> We don't run Zimbra, so I can't tell you about that. but we've had no trouble
> with the default config on things like mysql which want to bind only to 127.0.0.1.
> 
> But we don't have an "interfaces/0" directory either.  Perhaps there's some
> conflict there.  We changed them to match the actual host interface -
> interface/eth0, etc.  So you could try changing that and seeing if things work
> as expected.
> 
> HTH
> 
> Jeff Jansen
Thank you.  I wonder if I've really missed something in VServer
development.  It appears the /etc/vservers/<guest>/interfaces/
directories are made when the guest is created, e.g.:

vserver test01 build -m clone --hostname test01.mycompany.biz
--interface eth5:172.x.x.72/24 -- --source centos-base

This would create a directory under interfaces named 0 (zero) with files
dev (eth5), ip (172.x.x.72), and prefix (24)

We never thought to change them from the defaults to the eth device
names.  Should we? Thanks for the input - John
-- 
John A. Sullivan III
Open Source Development Corporation
+1 207-985-7880
jsullivan@opensourcedevel.com

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