[ovs-dev] [PATCH v2] ovsdb-server: Allow replication from older schema version servers.

Ben Pfaff blp at ovn.org
Thu Oct 24 21:25:29 UTC 2019

On Mon, Oct 21, 2019 at 10:26:51PM +0530, numans at ovn.org wrote:
> From: Numan Siddique <numans at ovn.org>
> Presently, replication is not allowed if there is a schema version mismatch between
> the schema returned by the active ovsdb-server and the local db schema. This is
> causing failures in OVN DB HA deployments during uprades.
> In the case of OpenStack tripleo deployment with OVN, OVN DB ovsdb-servers are
> deployed on a multi node controller cluster in active/standby mode. During
> minor updates or major upgrades, the cluster is updated one at a time. If
> a node A is running active OVN DB ovsdb-servers and when it is updated, another
> node B becomes active. After the update when OVN DB ovsdb-servers in A are started,
> these ovsdb-servers fail to replicate from the active if there is a schema
> version mismatch.
> This patch addresses this issue by allowing replication even if there is a
> schema version mismatch only if all the active db schema tables and its colums are
> present in the local db schema.
> This should not result in any data loss.

I applied this to master.  I made a few superficial changes to log
messages and style.

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