Re: [ovs-dev] [PATCH ovn] ovn-northd: Add the option to configure probe interval

[Girish Moodalbail]

Hello Numan,

We found a minor issue with this patch in our OVN K8s setup. Say, we have set the northd_probe_interval to 50ms, and we have 3 instances of `ovn-northd` running. In this setup, one of the ovn-northd instances will be active, whilst the remaining two instances will be in 'standby' mode. 

From my reading of ovn-northd.c`main(), the active instance will read the northd_probe_interval value and set it on its NB and SB IDLs. However, for the two standby instances we wouldn't have set that value on their NB and SB IDLs. Until all the standby instances become active, they will still have the default inactivity probe interval value of 5sec. 

So, in a large k8s cluster we are seeing that the standby ovn-northd instances are not able to latch on to connections for a long time due to the short inactivity probe interval value.

Regards,

~Girish

On Wed, Mar 4, 2020 at 10:54 PM Numan Siddique <num...@ovn.org> wrote:

On Thu, Mar 5, 2020 at 11:40 AM Girish Moodalbail
<gmood...@nvidia.com> wrote:
>
> Hello Numan,
>
> On 3/4/20, 9:58 PM, "Numan Siddique" <num...@ovn.org> wrote:
>
>     External email: Use caution opening links or attachments
>
>
>     On Thu, Mar 5, 2020 at 10:22 AM Girish Moodalbail
>     <gmood...@nvidia.com> wrote:
>     >
>     > Hello Numan,
>     >
>     > Thank you for getting this done __.
>     >
>     > Quick comment: The option set on NB_Global also affects ovn-northd's connection to OVN SB as well. Typically, one would expect any option on NB_Global should affect ovsdb-server managing OVN NB DB alone, right? Should we add similar option to SB_Global as well?
>
>     Hi Girish,
>
>     This newly added option probe_interval (which will be renamed to
>     northd_probe_interval) applies to both Northbound and Southbound
>     connections from ovn-northd.
>     So there is no need to add in SB_Global. And CMS is not supposed to do
>     any write txns to Southbound db.
>
> I see. If that is the case, then one option should be fine then.

Thanks  Han and Girish for the review and comments.

I applied this patch to master with the changes suggested by Han.

Thanks
Numan

>
> Regards,
> ~Girish
>
>
>
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