Open Stack

On Sat, Mar 29, 2014 at 11:53:13AM -0400, Mike Spreitzer wrote:
> I run into trouble in Ubuntu VMs when avahi-autoipd is installed. 
> After avahi-autoipd is installed, there is an extra route (number 2 in the 
> [...]
> Of course, avahi-autoipd thinks it is doing me a favor.  Nova thinks it is 
> doing me harm.  Which is right, and how do we achieve harmony?

Why are you installing avahi-autoipd in your cloud instance?  The
autoipd tool is used for configuring network interfaces in the absence
of either a static configuration or a functioning dhcp
environment...and because you're running in a cloud environment,
you're pretty much guaranteed the latter.

If you really want zeroconf networking to be functional inside your
instances while at the same time maintaining access to the OpenStack
metadata service, you could add an explicit route to the metadata
address via your default gateway.  For example, given:

    # ip route
    default via 10.0.0.1 dev eth0  metric 100 
    10.0.0.0/24 dev eth0  proto kernel  scope link  src 10.0.0.4 
    169.254.0.0/16 dev eth0  scope link  metric 1000 

I would add:

  ip route add 169.254.169.254 via 10.0.0.1

And this restores access to the metadata service.  This forces the
kernel to pass traffic to 169.254.169.254 to the gateway, rather than
assuming it's accessible via a local network.

-- 
Lars Kellogg-Stedman <lars at redhat.com> | larsks @ irc
Cloud Engineering / OpenStack          | "   "  @ twitter

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