[ovs-dev] [PATCH v2 7/9] ovsdb: relay: Reflect connection status in _Server database.

Dumitru Ceara dceara at redhat.com
Tue Jul 13 16:10:42 UTC 2021


On 7/13/21 1:25 AM, Ilya Maximets wrote:
> On 6/25/21 3:34 PM, Dumitru Ceara wrote:
>> On 6/12/21 4:00 AM, Ilya Maximets wrote:
>>> It might be important for clients to know that relay lost connection
>>> with the relay remote, so they could re-connect to other relay.
>>>
>>> Signed-off-by: Ilya Maximets <i.maximets at ovn.org>
>>> ---
>>
>> [...]
>>
>>>  
>>> +#define RELAY_MAX_RECONNECTION_MS 30000
>>
>> 30 seconds of relay "incorrectly" reporting that it is connected to the
>> source seems quite long.  Also, should we make this configurable?
> 
> We can make it configurable in the future.
> However, relays are meant to have multiple remotes, i.e. all servers

This had slipped my mind when initially reviewing the change.

> of a main ovsdb cluster, and they will re-connect between them as soon
> as disconnection detected (by inactivity probe or in other way).
> So, the case where relay is not connected to the source for a very long
> time is twofold:
> 
> 1. All main servers are down.
>    We can't really do anything in this case, and it doesn't matter if
>    clients know about this or not, as they have no place to re-connect
>    anyway.
> 
> 2. Our relay for some reason is not able to reach any of the main
>    servers, but still has connection with clients.  This case seems to
>    be rare and it's likely that clients are split from the rest of the
>    network along with their relay.  It seems also unlikely that
>    re-connection to a different relay will make any difference in this
>    scenario.
> 
> All in all, I don't think that it's necessarily a bad thing to keep
> clients connected for extra 30 seconds, because if relay is not able to
> re-connect, than it's unlikely that clients will be able to do that.

Make sense, thanks for the explanation!

I think it's fine to keep it as is for now.

> 
> As I said, we can make this value configurable in the future, if there
> will be need for it.
> 
> What do you think?

Sounds good, should be an easy change if needed in the future.

> 
> Best regards, Ilya Maximets.
> 

Regards,
Dumitru



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