[ovs-discuss] [ovs-dev] [OVN] stale data complained by ovn-controller after db restore

[Han Zhou]

On Tue, Aug 4, 2020 at 10:30 AM Tony Liu <tonyliu0592 at hotmail.com> wrote:

> Hi,
>
> Here is how I restore OVN DB.
> * Stop all ovn-nb-db, ovn-sb-db and ovn-northd services.
> * Clean up all DB files.
> * Start all DB services. Fresh ovn-nb-db and ovn-sb-db clusters are up and
>   running.
> * Set DB election timer to 10s.
> * Restore DB to ovn-nb-db by ovsdb-client.
> * Start all ovn-northd services.
>
> A few minutes after, ovn-sb-db is fully synced with ovn-nb-db.
>
> Now, the client of ovn-sb-db, ovn-controller and nova-compute complaint
> about
> "stale data". The chassis node is not getting updated.
> ========
> 2020-08-04 09:07:45.892 26 INFO ovsdbapp.backend.ovs_idl.vlog [-] tcp:
> 10.6.20.84:6642: connected
> 2020-08-04 09:07:45.895 26 WARNING ovsdbapp.backend.ovs_idl.vlog [-] tcp:
> 10.6.20.84:6642: clustered database server has stale data; trying another
> server
> ========
>
> Restarting ovn-controller and nova-compute resolve the issue.
>
> Is this expected? As part of the DB restore process, should I restart
> ovn-controller and nova-compute on all chassis node?
>
>
Yes, this is expected if you freshly start a new cluster. (It wouldn't
happen if you simply restore the old data on the existing cluster. However,
I understand that the scenario of restoring data on a freshly created
cluster is a valid use case).
For this case, you could either restart ovn-controller, or trigger a client
side raft index reset by:
    ovn-appctl -t ovn-controller sb-cluster-state-reset

Similarly for ovn-northd:
    ovn-appctl -t ovn-northd nb-cluster-state-reset
    ovn-appctl -t ovn-northd sb-cluster-state-reset

To use this command, you will need at least 20.06 of OVN and OVS master.

Thanks,
Han



> Thanks!
>
> Tony
>
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