[ovs-dev] ovn: Improving southbound database security

[Numan Siddique]

We may have to add one more item in the task breakdown list. Please see
below


On Wed, Oct 12, 2016 at 11:21 PM, Russell Bryant <russell at ovn.org> wrote:

> Hello, I'm back to looking at southbound database security concerns in
> OVN.  A previous thread discussing approaches was here:
>
>     http://openvswitch.org/pipermail/dev/2016-August/078106.html
>
> I'm now working with a few others on implementing a proposed solution.
> The overview is that we'd like to make ovn-controller a read-only client of
> the southbound database.
>
> The task breakdown is:
>
> 1) Add support to ovsdb-server for read-only remotes.  The port reachable
> by ovn-controller would only accept read-only connections.
>
> 2) Remove support from ovn-controller for automatically creating chassis
> and encap records.  Document this as an administrative step for adding a
> new chassis to the system, instead.
>
> 3) Remove support from ovn-controller for setting the chassis column of
> Port_Binding records.  Instead, have this handled by ovn-northd based on
> binding instructions given in the northbound database.
>
> As a nice side effect, this helps solve one of the difficulties with live
> migration (two chassis fighting to own a port while the migration is in
> progress).  Instead, we would update OVN when we know the migration is
> complete.
>
> I was originally thinking we may need an upgrade utility to help existing
> environments, but I think ovn-northd can handle this automatically.
>
> For the northbound database, I was thinking of adding a new option for
> logical ports called "chassis" with a value of the hostname of the chassis
> the port should be bound to.
>
> 4) Remove use of MAC_bindings table from ovn-controller.  Replace it with
> a local cache, instead.  I'm proposing just keeping it in memory in
> ovn-controller, but we could also make use of the openvswitch db.
>
> One detail I haven't fully thought through: what should happen to the
> MAC_Bindings table?  Dropping the table seems not backwards compatible and
> would break a rolling upgrade scenario.  Should we leave it as unused for
> one release, and then remove it in the next release?  More generally, I
> think we need to document our upgrade strategy and related rules for
> database schema changes.
>
>
​5) Remove support from ovn-controller updating the 'Chassis.hv_cfg'
column​ and handle the side effect in "--wait=hv" in ovn-nbctl.


-- 
> Russell Bryant
>