[Lxc-users] updated lxc template for debian squeeze - with attachedscript ; )

[Michael H. Warfield]

On Fri, 2011-03-11 at 10:14 -0500, Michael H. Warfield wrote: 
> On Thu, 2011-03-10 at 19:09 +0000, Walter Stanish wrote: 
> > >>> ...  I have read up on the OUI documentation and
> > >>> looking at the detail on the site LXC could opt for a 32bit OUI which would
> > >>> cost $600 for one block. The dev guys might want to setup a pledge program...
> > 
> > >> I will pay for it.
> > 
> > > I too am willing to pay the whole thing, so, halvsies? Or see how many
> > > others want to split even?
> 
> > Sounds good.  I guess we can nominate you as the finance go-to on this
> > one then :)
> 
> > Let us know details when they emerge.
> 
> Can someone explain to me why we can't simply use a block of addresses
> with the 0200 (local administration) bit or'ed in.  Out of 48 bits of
> addressing, we can use 46 bits of them for anything we want as long as
> that bit is set and the 0100 bit (multicast) is clear.  By the standard,
> those are locally managed and allocated MAC addresses that are not
> guaranteed to be globally unique.  They don't even need to be unique in
> an entire network, only on the local subnet.  Use any convention you
> want.  Stuff the 32 bit IP address of the host in the lower 32 bits and
> you've still got 14 bits worth of assignable addressing per host.
> That's what that bit is intended for.

Another reason we may want do to this is a little more obscure.  The MAC
address of a Linux bridge is the numerically lowest MAC address of the
attached interfaces.  If you are using bridged networking and the
containers have a MAC addresses lower than that of the host, the bridge
will change MAC addresses as the containers are started and stopped.
Since the host interface is a member of that bridge, the host's
effective MAC address to the rest of the network also effectively
changes as containers open and close.  This is a bad thing.  It can
cause temporary transient network delays and glitching in the ARP cache
on IPv4 and generally raise havok on IPv6.  Choosing something arbitrary
with a couple of high order bits set (say C2:xx:xx:xx:xx:xx) helps
insure that the containers have higher addresses than the host interface
and will not cause dynamic changes in the MAC addresses of the bridges.

> > - Walter
> > 
> > ------------------------------------------------------------------------------
> > Colocation vs. Managed Hosting
> > A question and answer guide to determining the best fit
> > for your organization - today and in the future.
> > http://p.sf.net/sfu/internap-sfd2d
> 
> 
> ------------------------------------------------------------------------------
> Colocation vs. Managed Hosting
> A question and answer guide to determining the best fit
> for your organization - today and in the future.
> http://p.sf.net/sfu/internap-sfd2d
> _______________________________________________ Lxc-users mailing list Lxc-users at lists.sourceforge.net https://lists.sourceforge.net/lists/listinfo/lxc-users

-- 
Michael H. Warfield (AI4NB) | (770) 985-6132 |  mhw at WittsEnd.com
   /\/\|=mhw=|\/\/          | (678) 463-0932 |  http://www.wittsend.com/mhw/
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