Re: [vserver] util-vserver & cpuset bug ?

From: Michael S. Zick <mszick_at_morethan.org>
Date: Thu 16 Jul 2009 - 13:26:59 BST
Message-Id: <200907160727.04288.mszick@morethan.org>

On Wed July 15 2009, Ed W wrote:
> Hi
>
> > well, you have a bunch of options, depending on the
> > specific usecase ... e.g.
> >
>
> Assuming headless server somewhere in a rack.
>
> > - use a real console (serial or vga)
> > - use a virtual console
> >
>
> Excuse dim question, but presumably the latter (and former) of these is
> out if we aren't on the physical terminal?
>
> > - use a pipe or unix socket
> > - use a network socket
> >
>
> Again, probably dim question, but by this do you mean some variation of
> ssh, telnet or home grown equivalent using netcat/shells, etc?
>
> >> SSH is a given, but isn't always a straightforward option
> >> if IP addresses are constrained
> >>
> >
> > AFAIK, there is no constraint on private IP addresses
> > (yet, although the IPV6 folks would like to see that
> > on IPV4 :), so the public IP address constrains are
> > not a real reason for not using ssh or telnet
> >
>
> Well, kind of. However, it's certainly more convenient to run all
> services on port 22 on real IPs.
>
> At least for my data center machines I obviously need to talk to real
> IPs at some point and obviously one IP is enough if use an array of
> ports, but remembering how they all map is a pain. Someone will say to
> configure some file in ~/.ssh which lets you setup these mappings, but I
> hop around between a bunch of linux, windows and mac terminals and
> keeping such a file up to date is not ideal. (DNS solves the problem
> neatly in the case of lots of IPs!)
>
> I guess it would be possible to setup a gateway (vserver?) which you ssh
> into and then from there into the real server. Add some scripts and I
> can see that working
>

That works for me. My host box is the only one with an "outside" IP address;
Once I ssh into it, I can then ssh into any of its guests.
(Or "vserver name enter" if that is what you need to use.)
Just as if they where all physically different machines in the rack.
(I have one busy little core2quad used to host multiple developement
environments / distributions.)

Of course this doesn't work if the host context is down,
but then neither do the guest contexts. ;)

Mike
> However, quite often when I'm doing maintenance and leaping into
> machines to check config (and some machines are just templates, so they
> get fired up with incorrect ip addresses), it's definitely extremely
> convenient to be able to use "enter"
>
> Grateful for any other ideas?
>
> Thanks
>
> Ed W
>
Received on Thu Jul 16 13:27:32 2009

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