[MidoNet] Data stored in Cassandra / DHCP IP addresses

Jan Hilberath jan at midokura.com
Tue Nov 11 08:53:14 UTC 2014


Hi Pino,

Thanks for the clarification!

Jan


On 11/11/2014 05:50 PM, Giuseppe (Pino) de Candia wrote:
> On Tue, Nov 11, 2014 at 8:37 AM, Jan Hilberath <jan at midokura.com 
> <mailto:jan at midokura.com>> wrote:
>
>     Hi All,
>
>     Is there any document (or can anyone provide the info here) about
>     what data is being stored in Cassandra?
>
>
> Hi Jan,
>
> I can't answer regarding where this is documented. However, the 
> Cassandra question has come up before and there may be a ticket open 
> about it.
>
> Cassandra is used only to store per-flow data (connection-tracking, 
> dynamic NAT and LB decisions). Since v1.6, this data is also passed 
> directly between MN Agents that need it (ingress hosts of forward and 
> return flows) at flow creation time and stored locally; the data in 
> Cassandra is only used on node reboot or VM migration (cases when the 
> Agent loses or doesn't have local flow state).
>
>
>     For example, the IP address a VM receives via DHCP, where is that
>     stored?
>
>
> This is stored in ZooKeeper in the DHCPSubnet object (and MacIP 
> sub-object). This object gets created inside MN when the Neutron 
> Subnet is created. It's populated with MacIP objects each time a new 
> Neutron Network Port is created (and therefore and IP and MAC assigned 
> by Neutron to the port).
>
>
>     My understanding is that a VM get's the same DHCP IP address on
>     every reboot (guess mapped to the MAC).
>
>
> Correct.
>
>     Assuming I clean all Cassandra data, will my VM still receive the
>     same DHCP IP address?
>
>
> As should already be clear from above, Cassandra is not involved in 
> the DHCP.
>
> thanks for the questions! Please keep them coming and let's try to get 
> all this into the docs.
>
> --Pino
>
>
>     Thanks,
>     Jan
>
>     _______________________________________________
>     MidoNet mailing list
>     MidoNet at lists.midonet.org <mailto:MidoNet at lists.midonet.org>
>     http://lists.midonet.org/listinfo/midonet
>
>

-------------- next part --------------
An HTML attachment was scrubbed...
URL: <http://lists.midonet.org/pipermail/midonet/attachments/20141111/e17668c6/attachment.html>


More information about the MidoNet mailing list