openstack team mailing list archive

[Calvin Walton <calvin.walton@xxxxxxxxxx>]

On Thu, 2012-08-02 at 13:59 -0400, Lars Kellogg-Stedman wrote:
> If I create a floating address range like this:
> 
>   nova-manage floating create --ip_range=10.243.30.0/24
> 
> Is there any way to "block out" specific addresses in that range?  For
> example, the .1 address is the network gateway, and everything will
> fall apart if that address is accidentally allocated to an instance.
> 
> Similarly, our host needs an address in that range in order to route
> traffic to the gateway.
> 
> Is there any way to exempt specific addresses?  I realize that instead
> of allocating a /24 I could allocate a series of, say, /28 networks,
> but that seems a little clumsy.

(The following is assuming you're using Essex - I don't really know
anything about Quantum)

An interesting thing about how floating IPs work is that internally
nova-network just has a big table of ip addresses in the database. The
only thing that using a CIDR range like "10.243.20.0/24" does is save
you some typing - it does the exact same thing as separately adding
"10.243.20.1", "10.243.20.2", and so on.

So it really makes no difference if you just individually add the ip
addresses that you want to use.

The easiest alternative? Just add the entire /24 range, then delete the
individual addresses that you want to reserve using
nova-manage floating delete 10.243.30.1
and so on.

-- 
Calvin Walton <calvin.walton@xxxxxxxxxx>