Bumping :)
If there are no objections, I'd like to go with the following:
1. Do not support javaapi (SimpleConsumer) with dependency on versions
higher than 0.8.2. Existing clients will keep working.
2. The configuration parameter for upgrades will be
inter.broker.protocol.version={0.8.2.0, 0.8.3.0, 0.9.0.0...}
Gwen
On Mon, Jan 26, 2015 at 8:02 PM, Gwen Shapira <gshap...@cloudera.com> wrote:
> Hi Kafka Devs,
>
> While reviewing the patch for KAFKA-1809, we came across two questions
> that we are interested in hearing the community out on.
>
> 1. This patch changes the Broker class and adds a new class
> BrokerEndPoint that behaves like the previous broker.
>
> While technically kafka.cluster.Broker is not part of the public API,
> it is returned by javaapi, used with the SimpleConsumer.
>
> Getting replicas from PartitionMetadata will now return BrokerEndPoint
> instead of Broker. All method calls remain the same, but since we
> return a new type, we break the API.
>
> Note that this breakage does not prevent upgrades - existing
> SimpleConsumers will continue working (because we are
> wire-compatible).
> The only thing that won't work is building SimpleConsumers with
> dependency on Kafka versions higher than 0.8.2. Arguably, we don't
> want anyone to do it anyway :)
>
> So:
> Do we state that the highest release on which SimpleConsumers can
> depend is 0.8.2? Or shall we keep Broker as is and create an
> UberBroker which will contain multiple brokers as its endpoints?
>
> 2.
> The KIP suggests "use.new.wire.protocol" configuration to decide which
> protocols the brokers will use to talk to each other. The problem is
> that after the next upgrade, the wire protocol is no longer new, so
> we'll have to reset it to false for the following upgrade, then change
> to true again... and upgrading more than a single version will be
> impossible.
> Bad idea :)
>
> As an alternative, we can have a property for each version and set one
> of them to true. Or (simple, I think) have "wire.protocol.version"
> property and accept version numbers (0.8.2, 0.8.3, 0.9) as values.
>
> Please share your thoughts :)
>
> Gwen
