[ovs-dev] ovsdb active backup deployment

[Russell Bryant]

On Thu, Aug 18, 2016 at 2:30 AM, Valentine Sinitsyn <
valentine.sinitsyn at gmail.com> wrote:

> Hi everyone,
>
> Russell, Would HA manager also manage ovn-controller switch over?
>>>>
>>>>
>>> Yes, indirectly.  The way this is typically handled is by using a virtual
>>> IP that moves to whatever host is currently the master
>>>
>>> Cool, then ovn-controller does not have to be HA aware.
>>
>
> In my understanding, the virtual IP feature in Pacemaker (i.e. IPaddr2)
> works if both active and passive nodes of the cluster are in the same IP
> subnet.
>
> For some deployments, this would mean both nodes a located on the same
> physical rack. This is not actually a fault-tolerant design (think
> blackout).
>
> If I'm getting virtual IP addresses in Pacemaker correct, wouldn't it be
> better to make ovn-controller HA aware? That is, have a node switching
> command (akin to ovsdb-server/connect-active-ovsdb-server) and let
> Pacemaker make use it?
>

I was not planning to have pacemaker manage ovn-controller on every host.


> If this sounds reasonable, I can take on it probably.
>

In general, I think having ovn-controller able to connect to more than one
database IP seems fine.  I don't expect everyone to necessarily agree on
the same HA architecture.

Perhaps it's simple and good enough to add some support for multiple IP
addresses for the southbound database that ovn-controller can rotate
through on reconnect attempts?

-- 
Russell Bryant