← Back to team overview

openstack team mailing list archive

Re: Quantim duplicate subnet creation



Yup this is definitely possible. The reason why this isn't set by default
is that some distros don't ship kernels that build with CONFIG_NET_NS=y or
their iproute2 package is to outdated to support linux namespaces.  Also,
until recently nova's metadata service didn't support overlapping ips. If
you are running ubuntu 12.04 you should be able to set:


in your localrc to enable this.

or edit your quantum.conf here and restart quantum to enable overlapping

# Enable or disable overlapping IPs for subnets
# Attention: the following parameter MUST be set to False if Quantum is
# being used in conjunction with nova security groups and/or metadata
# allow_overlapping_ips = False


p.s: I don't think this will work in a flat network setup though since
there is no way to isolate that. What plugin are you using?
> I have the following networks in a flat network setup.

On Thu, Jan 17, 2013 at 2:52 AM, Balamurugan V G <balamuruganvg@xxxxxxxxx>wrote:

> Hi,
> Is there a way to create a duplicate network/subnet for tenant in quantum.
> Basically for a tenant, I want to have some instances(GroupA) share a
> subnet and another set of instances(GroupB) share the same(duplicate)
> subnet but GroupA and GroupB should be isolated. I have labnet which is the
> flat network to which one instance from each group is assigned for external
> connectivity. Then I want to have two private networks private1 and
> private2 both sharing the same subnet but I was to assign some instances to
> private1 and some in private2.
> I have the following networks in a flat network setup.
> root@openstack:~# quantum subnet-list
> +--------------------------------------+------+------------------+------------------------------------------------------+
> | id                                   | name | cidr             |
> allocation_pools                                     |
> +--------------------------------------+------+------------------+------------------------------------------------------+
> | abb62a74-ad15-452c-857f-ee0a1b388ede |      | |
> {"start": "", "end": ""} |
> | eedc0c12-c3ed-42ce-a860-692e766087a2 |      |     |
> {"start": "", "end": ""}         |
> +--------------------------------------+------+------------------+------------------------------------------------------+
> root@openstack:~#
> Now, the following gets denied.
> root@openstack:~# quantum subnet-create --tenant-id
> 7cda178971e84c5194c8531bf4f229d7  private2
> Invalid input for operation: Requested subnet with cidr: network: 64ec75d6-0c6f-44e1-a268-b573324c4160 overlaps with another
> subnet.
> root@openstack:~#
> I understand that a duplicate network with a tenant is not a common
> scenario and perhaps by design its not allowed.
> But there could be cases like I mentioned.
> Strangely, I am not allowed to create the duplicate network even across
> tenants. Atleast this should be allowed.
> BTW, I am running a single node Devstack.
> Regards,
> Balu
> _______________________________________________
> Mailing list: https://launchpad.net/~openstack
> Post to     : openstack@xxxxxxxxxxxxxxxxxxx
> Unsubscribe : https://launchpad.net/~openstack
> More help   : https://help.launchpad.net/ListHelp

Follow ups