I am using storm-kafka-client 1.2.1 and creating my spout config for KafkaTridentSpoutOpaque as below
kafkaSpoutConfig = KafkaSpoutConfig.builder(brokerURL, kafkaTopic)
.setProp(ConsumerConfig.GROUP_ID_CONFIG,"storm-kafka-group")
.setProcessingGuarantee(ProcessingGuarantee.AT_MOST_ONCE)
.setProp(ConsumerConfig.CLIENT_ID_CONFIG,InetAddress.getLocalHost().getHostName())
I am unable to find neither my group-id nor the offset in both Kafka and Zookeeper. Through Zookeeper I tried with zkCli.sh and tried ls /consumers but there were none as I think Kafka itself is now maintaining offsets rather than zookeeper.
I tried with Kafka too with the command below
bin/kafka-run-class.sh kafka.admin.ConsumerGroupCommand --list --bootstrap-server localhost:9092
Note: This will not show information about old Zookeeper-based consumers.
console-consumer-20130
console-consumer-82696
console-consumer-6106
console-consumer-67393
console-consumer-14333
console-consumer-21174
console-consumer-64550
Can someone help me how I can find my offset and will it replay my events in Kafka again if I restart the topology ?
Trident doesn't store offsets in Kafka, but in Storm's Zookeeper. If you're running with default settings for Storm's Zookeeper config the path in Storm's Zookeeper will be something like /coordinator/<your-topology-id>/meta.
The objects below that path will contain the first and last offset, as well as topic partition for each batch. So e.g. /coordinator/<your-topology-id>/meta/15 would contain the first and last offset emitted in batch number 15.
Whether the spout replays offsets after restart is controlled by the FirstPollOffsetStrategy you set in the KafkaSpoutConfig. The default is UNCOMMITTED_EARLIEST, which does not start over on restart. See the Javadoc at https://github.com/apache/storm/blob/v1.2.1/external/storm-kafka-client/src/main/java/org/apache/storm/kafka/spout/KafkaSpoutConfig.java#L126.
Related
I have kafka topic configured with cleanup.policy=compact and retention.ms=-1 - so infinite retention.
What I want to do is change it, I want the events to be compacted time to time. When I create new topic with following configuration it works fine:
cleanup.policy=compact
config retention.ms=5000
min.cleanable.dirty.ratio=0
segment.ms=1000
When I produce events to such topic it is compacted as expected.
Problem is when I have topic with retention set to infinite (-1), and change it's config by kafka-configs --alter. Using kafka-topics --describe I can verify that the changes were successful, but the topic is not compacted. How can I "trigger" those config changes? I also tried restarting the broker and zookeeper, but it didn't do the trick.
I'm using kafka 2.7.0
I have a Kafka cluster consisting on 3 servers all connected through Zookeeper. But when I delete a topic that has some information and create the topic again with the same name, the offset does not start from zero.
I tried restarting both Kafka and Zookeeper and deleting the topics directly from Zookeeper.
What I expect is to have a clean topic When I create it again.
I found the problem. A consumer was consuming from the topic and the topic was never actually deleted. I used this tool to have a GUI that allowed me to see the topics easily https://github.com/tchiotludo/kafkahq. Anyway, the consumers can be seen running this:
bin/kafka-consumer-groups.sh --list --bootstrap-server localhost:9092
What is the "offsets.storage" for kafka 0.10.1.1?
As per the documentation it shows up under Old Consumer Configs as "zookeeper".
offsets.storage zookeeper Select where offsets should be stored (zookeeper or kafka).
My consumer is spring-boot-1.5.13 RELEASE app which uses kafka-clients-0.10.1.1 internally. As per the source code ConsumerConfig.scala, offsetStorage is "zookeeper", but when I run the consumer, I see the "__consumer_offsets" are getting created under /tmp/kafka-logs directory which is defined in server.properties [i.e. broker];
Moreover it doesn't show up under zookeeper ephemeral nodes, when I check with zookeeper-shell.sh.
ls /consumers
[]
If the offsets.stroage is zookeeper, then why does the __consumer_offsets show up under /tmp/kafka-logs and doesn't show up in zookeeper ephemeral nodes?
Spring Kafka uses the "new" consumer (Java) not the old scala consumer.
I am using Apache Kafka in (Plain Vanilla) Hadoop Cluster for the past few months and out of curiosity I am asking this question. Just to gain additional knowledge about it.
Kafka server.properties file already has the below parameter :
zookeeper.connect=localhost:2181
And I am starting Kafka Server/Broker with the following command :
bin/kafka-server-start.sh config/server.properties
So I assume that Kafka automatically infers the Zookeeper details by the time we start the Kafka server itself. If that's the case, then why do we need to explicitly mention the zookeeper properties while we create Kafka topics the syntax for which is given below for your reference :
bin/kafka-topics.sh --create --zookeeper localhost:2181
--replication-factor 1 --partitions 1 --topic test
As per the Kafka documentation we need to start zookeeper before starting Kafka server. So I don't think Kafka can be started by commenting out the zookeeper details in Kafka's server.properties file
But atleast can we use Kafka to create topics and to start Kafka Producer/Consumer without explicitly mentioning about zookeeper in their respective commands ?
The zookeeper.connect parameter in the Kafka properties file is needed for having each Kafka broker in the cluster connecting to the Zookeeper ensemble.
Zookeeper will keep information about connected brokers and handling the controller election. Other than that, it keeps information about topics, quotas and ACL for example.
When you use the kafka-topics.sh tool, the topic creation happens at Zookeeper level first and then thanks to it, information are propagated to Kafka brokers and topic partitions are created and assigned to them (thanks to the elected controller). This connection to Zookeeper will not be needed in the future thanks to the new Admin Client API which provides some admin operations executed against Kafka brokers directly. For example, there is a opened JIRA (https://issues.apache.org/jira/browse/KAFKA-5561) and I'm working on it for having the tool using such API for topic admin operations.
Regarding producer and consumer ... the producer doesn't need to connect to Zookeeper while only the "old" consumer (before 0.9.0 version) needs Zookeeper connection because it saves topic offsets there; from 0.9.0 version, the "new" consumer saves topic offsets in real topics (__consumer_offsets). For using it you have to use the bootstrap-server option on the command line insteand of the zookeeper one.
I use zkCli.sh to list the kafka paths in zookeeper.
By the Kafka+data+structures+in+Zookeeper document,i find all paths in the doc can match the document,except consumers path.
Command ls /consumers,response [],But kafka manager of yahoo can get consumer info,such as LogSize,Consumer Offset and so on.
That's the new consumer which does not depend on Zookeeper anymore. Zk node '/consumers' is just for old consumers. The reason why you could find consumer info in KafkaManager might because it supports the new consumer already.
Kafka ships with a command kafka-consumer-groups.sh which can be used to check status for both old consumer and new consumer.