Create a topic
Let’s create a topic named “test” with a single partition and only one replica:
> bin/kafka-topics.sh --create --bootstrap-server localhost:9092 --replication-factor 1 --partitions 1 --topic test
We can now see that topic if we run the list topic command:
> bin/kafka-topics.sh --list --bootstrap-server localhost:9092
test
Start some messages
Kafka comes with a command line client that will take input from a file or from standard input and send it out as messages to the Kafka cluster. By default, each line will be sent as a separate message.
Run the producer and then type a few messages into the console to send to the server.
> bin/kafka-console-producer.sh --broker-list localhost:9092 --topic test
This is a message
This is another message
Start a consumer
Kafka also has a command line consumer that will dump out messages to standard output.
> bin/kafka-console-consumer.sh --bootstrap-server localhost:9092 --topic test --from-beginning
This is a message
This is another message
Understand random characters in the log file of kafka
> bin/kafka-run-class.sh kafka.tools.DumpLogSegments --deep-iteration --print-data-log --files topic/*.log|index|timeindex
Inspect kafka group
> bin/kafka-consumer-groups.sh --bootstrap-server localhost:9092 --group hiway.group.projection --describe -- state
| TOPIC | PARTITION | CURRENT-OFFSET | LOG-END-OFFSET | LAG | CONSUMER-ID | HOST | CLIENT-ID |
|---|---|---|---|---|---|---|---|
| hiway.topic.order | 0 | 6 | 6 | 0 | consumer-21-d8cb9666-2d54-408b-82a6-0480a0b5a10b | /172.168.5.9 | consumer-21 |
| hiway.topic.aps-billing | 0 | 10 | 10 | 0 | consumer-21-fbea0085-d5fa-4645-a2cf-c3b4e9f2837b | /172.168.0.7 | consumer-21 |
| hiway.topic.account | 0 | 23 | 23 | 0 | consumer-15-24e95c62-03f9-4051-8cd0-8b40d691b0c9 | /172.168.0.7 | consumer-15 |
Lookup for assigned of partition
> bin/kafka-consumer-groups.sh --bootstrap-server localhost:9092 --describe --members --group hiway.group.projection
| CONSUMER-ID | HOST | CLIENT-ID | #PARTITIONS |
|---|---|---|---|
| consumer-27-d56cb0ba-90a8-498a-b019-9f71c6046e03 | /172.168.0.7 | consumer-27 | 0 |
| consumer-6-cacd38dc-dffb-456c-b0d2-5badbb06f108 | /172.168.0.7 | consumer-6 | 0 |
| consumer-24-ba6ef6b7-d0fe-4104-a0e9-5bcda354cda8 | /172.168.0.7 | consumer-24 | 1 |
| consumer-21-d8cb9666-2d54-408b-82a6-0480a0b5a10b | /172.168.5.9 | consumer-21 | 1 |
| consumer-21-fbea0085-d5fa-4645-a2cf-c3b4e9f2837b | /172.168.0.7 | consumer-21 | 1 |
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