On Thu, Apr 30, 2015 at 2:15 AM, Nimi Wariboko Jr <n...@channelmeter.com> wrote:
> My mistake, it seems the Java drivers are a lot more advanced than the > Shopify's Kafka driver (or I am missing something) - and I haven't used > Kafka before. > > With the Go driver - it seems you have to manage offsets and partitions > within the application code, while in Scala driver it seems you have the > option of simply subscribing to a topic, and someone else will manage that > part. > > After digging around a bit more, I found there is another library - > https://github.com/wvanbergen/kafka - that speaks the consumergroup API > and > accomplishes what I was looking for and I assume is implemented by keeping > track of memberships w/ Zookeeper. > Yes. That library is built on top of Sarama (Shopify's Go kafka driver), and it's on our roadmap to integrate it properly. As far as I know, this is the only major area where Sarama is lagging behind the jvm client. > > Thank you for the information - it really helped clear up what I failing to > understand with kafka. > > Nimi > > On Wed, Apr 29, 2015 at 10:10 PM, Joe Stein <joe.st...@stealth.ly> wrote: > > > You can do this with the existing Kafka Consumer > > > > > https://github.com/apache/kafka/blob/0.8.2/core/src/main/scala/kafka/consumer/SimpleConsumer.scala#L106 > > and probably any other Kafka client too (maybe with minor/major rework > > to-do the offset management). > > > > The new consumer approach is more transparent on "Subscribing To Specific > > Partitions" > > > > > https://github.com/apache/kafka/blob/trunk/clients/src/main/java/org/apache/kafka/clients/consumer/KafkaConsumer.java#L200-L234 > > . > > > > Here is a Docker file (** pull request pending **) for wrapping kafka > > consumers (doesn't have to be the go client, need to abstract that out > some > > more after more testing) > > > > > https://github.com/stealthly/go_kafka_client/blob/mesos-marathon/consumers/Dockerfile > > > > > > Also a VM (** pull request pending **) to build container, push to local > > docker repository and launch on Apache Mesos > > > > > https://github.com/stealthly/go_kafka_client/tree/mesos-marathon/mesos/vagrant > > as working example how-to-do. > > > > All of this could be done without the Docker container and still work on > > Mesos ... or even without Mesos and on YARN. > > > > You might also want to checkout how Samza integrates with Execution > > Frameworks > > > > > http://samza.apache.org/learn/documentation/0.9/comparisons/introduction.html > > which has a Mesos patch https://issues.apache.org/jira/browse/SAMZA-375 > > and > > built in YARN support. > > > > ~ Joe Stein > > - - - - - - - - - - - - - - - - - > > > > http://www.stealth.ly > > - - - - - - - - - - - - - - - - - > > > > On Wed, Apr 29, 2015 at 8:56 AM, David Corley <davidcor...@gmail.com> > > wrote: > > > > > You're right Stevo, I should re-phrase to say that there can be no more > > > _active_ consumers than there are partitions (within a single consumer > > > group). > > > I'm guessing that's what Nimi is alluding to asking, but perhaps he can > > > elaborate on whether he's using consumer groups and/or whether the 100 > > > partitions are all for a single topic, or multiple topics. > > > > > > On 29 April 2015 at 13:38, Stevo Slavić <ssla...@gmail.com> wrote: > > > > > > > Please correct me if wrong, but I think it is really not hard > > constraint > > > > that one cannot have more consumers (from same group) than partitions > > on > > > > single topic - all the surplus consumers will not be assigned to > > consume > > > > any partition, but they can be there and as soon as one active > consumer > > > > from same group goes offline (its connection to ZK is dropped), > > consumers > > > > from the group will be rebalanced so one passively waiting consumer > > will > > > > become active. > > > > > > > > Kind regards, > > > > Stevo Slavic. > > > > > > > > On Wed, Apr 29, 2015 at 2:25 PM, David Corley <davidcor...@gmail.com > > > > > > wrote: > > > > > > > > > If the 100 partitions are all for the same topic, you can have up > to > > > 100 > > > > > consumers working as part of a single consumer group for that > topic. > > > > > You cannot have more consumers than there are partitions within a > > given > > > > > consumer group. > > > > > > > > > > On 29 April 2015 at 08:41, Nimi Wariboko Jr <n...@channelmeter.com > > > > > > wrote: > > > > > > > > > > > Hi, > > > > > > > > > > > > I was wondering what options there are for horizontally scaling > > kafka > > > > > > consumers? Basically if I have 100 partitions and 10 consumers, > and > > > > want > > > > > to > > > > > > temporarily scale up to 50 consumers, what options do I have? > > > > > > > > > > > > So far I've thought of just simply tracking consumer membership > > > somehow > > > > > > (either through Raft or zookeeper's znodes) on the consumers. > > > > > > > > > > > > > > > > > > > > >
