I think Jason was suggesting quiescent time as a possibility only if the broker did request forwarding if it is not the leader.
On Monday, June 24, 2013, Jun Rao wrote: > Jason, > > The quiescence time that you proposed won't work. The reason is that with > ack=0, the producer starts losing data silently from the moment the leader > is moved (by controlled shutdown) until the broker is shut down. So, the > sooner that you can shut down the broker, the better. What we realized is > that if you can use a larger batch size, ack=1 can still deliver very good > throughput. > > Thanks, > > Jun > > > On Mon, Jun 24, 2013 at 12:22 AM, Jason Rosenberg > <j...@squareup.com<javascript:;>> > wrote: > > > Yeah I am using ack = 0, so that makes sense. I'll need to rethink that, > > it would seem. It would be nice, wouldn't it, in this case, for the > broker > > to realize this and just forward the messages to the correct leader. > Would > > that be possible? > > > > Also, it would be nice to have a second option to the controlled shutdown > > (e.g. controlled.shutdown.quiescence.ms), to allow the broker to wait > > after > > the controlled shutdown, a prescribed amount of time before actually > > shutting down the server. Then, I could set this value to something a > > little greater than the producer's 'topic.metadata.refresh.interval.ms'. > > This would help with hitless rolling restarts too. Currently, every > > producer gets a very loud "Connection Reset" with a tall stack trace each > > time I restart a broker. Would be nicer to have the producers still be > > able to produce until the metadata refresh interval expires, then get the > > word that the leader has moved due to the controlled shutdown, and then > > start producing to the new leader, all before the shutting down server > > actually shuts down. Does that seem feasible? > > > > Jason > > > > > > On Sun, Jun 23, 2013 at 8:23 PM, Jun Rao <jun...@gmail.com<javascript:;>> > wrote: > > > > > Jason, > > > > > > Are you using ack = 0 in the producer? This mode doesn't work well with > > > controlled shutdown (this is explained in FAQ i*n > > > https://cwiki.apache.org/confluence/display/KAFKA/Replication+tools#)* > > > * > > > * > > > Thanks, > > > > > > Jun > > > > > > > > > On Sun, Jun 23, 2013 at 1:45 AM, Jason Rosenberg > > > <j...@squareup.com<javascript:;> > > > > wrote: > > > > > > > I'm working on trying on having seamless rolling restarts for my > kafka > > > > servers, running 0.8. I have it so that each server will be > restarted > > > > sequentially. Each server takes itself out of the load balancer > (e.g. > > > sets > > > > a status that the lb will recognize, and then waits more than long > > enough > > > > for the lb to stop sending meta-data requests to that server). Then > I > > > > initiate the shutdown (with controlled.shutdown.enable=true). This > > seems > > > > to work well, however, I occasionally see warnings like this in the > log > > > > from the server, after restart: > > > > > > > > 2013-06-23 08:28:46,770 WARN [kafka-request-handler-2] > > server.KafkaApis > > > - > > > > [KafkaApi-508818741] Produce request with correlation id 7136261 from > > > > client on partition [mytopic,0] failed due to Leader not local for > > > > partition [mytopic,0] on broker 508818741 > > > > > > > > This WARN seems to persistently repeat, until the producer client > > > initiates > > > > a new meta-data request (e.g. every 10 minutes, by default). > However, > > > the > > > > producer doesn't log any errors/exceptions when the server is logging > > > this > > > > WARN. > > > > > > > > What's happening here? Is the message silently being forwarded on to > > the > > > > correct leader for the partition? Is the message dropped? Are these > > > WARNS > > > > particularly useful? > > > > > > > > Thanks, > > > > > > > > Jason > > > > > > > > > >
