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Apache Kafka Three Ways: CLI Tools

Provides the facility to start and operate an Apache Kafka cluster locally via Docker and Docker-Compose.

Use in unison with TW AK3W Workshop.

In the morning session (theory):

Demonstrates the ergonimics of running a simple three node Kafka Cluster locally, and to reinforce ideas introduced.

In the afternoon session (practical):

Provides a local Kafka cluster when solving the mystery of the Number Stations.

Troubleshooting

Docker

If you are having problems with docker similar to the following error messages, try restarting docker:

driver failed programming external connectivity on endpoint
-----
input/output error

Initialize and Monitor a Cluster

Note: These broker nodes are accessible on localhost:8082, 8083, and 8083.

Start a 3-node Kafka Cluster and enter a shell with all kafka-tools scripts:

docker-compose down
docker-compose up -d
docker-compose -f docker-compose.tools.yml run kafka-tools

In a new terminal, view the running kafka logs:

docker-compose logs -f

Use the Shell Scripts

From within the tools shell.

Confirm the kafka nodes are visible:

# ping kafka-1

PING kafka-1 (172.27.0.5) 56(84) bytes of data.
64 bytes from apache-kafka-cli-tools_kafka-1_1.apache-kafka-cli-tools_default (172.27.0.5): icmp_seq=1 ttl=64 time=0.093 ms
64 bytes from apache-kafka-cli-tools_kafka-1_1.apache-kafka-cli-tools_default (172.27.0.5): icmp_seq=2 ttl=64 time=0.112 ms

Create a new Topic 'x-topic' with 12 partitions and RF=3:

# ./bin/kafka-topics.sh --bootstrap-server kafka-1:19092 --create --topic x-topic --partitions 12 --replication-factor 3

Confirm the new topic has been created:

# ./bin/kafka-topics.sh --bootstrap-server kafka-1:19092 --list

x-topic

Describe the new topic:

# ./bin/kafka-topics.sh --bootstrap-server kafka-1:19092 --describe --topic x-topic

Topic:x-topic	PartitionCount:12	ReplicationFactor:3	Configs:
	Topic: x-topic	Partition: 0	Leader: 1	Replicas: 1,2,3	Isr: 1,2,3
	Topic: x-topic	Partition: 1	Leader: 2	Replicas: 2,3,1	Isr: 2,3,1
	Topic: x-topic	Partition: 2	Leader: 3	Replicas: 3,1,2	Isr: 3,1,2
	Topic: x-topic	Partition: 3	Leader: 1	Replicas: 1,3,2	Isr: 1,3,2
	Topic: x-topic	Partition: 4	Leader: 2	Replicas: 2,1,3	Isr: 2,1,3
	Topic: x-topic	Partition: 5	Leader: 3	Replicas: 3,2,1	Isr: 3,2,1
	Topic: x-topic	Partition: 6	Leader: 1	Replicas: 1,2,3	Isr: 1,2,3
	Topic: x-topic	Partition: 7	Leader: 2	Replicas: 2,3,1	Isr: 2,3,1
	Topic: x-topic	Partition: 8	Leader: 3	Replicas: 3,1,2	Isr: 3,1,2
	Topic: x-topic	Partition: 9	Leader: 1	Replicas: 1,3,2	Isr: 1,3,2
	Topic: x-topic	Partition: 10	Leader: 2	Replicas: 2,1,3	Isr: 2,1,3
	Topic: x-topic	Partition: 11	Leader: 3	Replicas: 3,2,1	Isr: 3,2,1

Show the offsets of each partition in the new topic:

# ./bin/kafka-run-class.sh kafka.tools.GetOffsetShell --broker-list kafka-1:19092 --topic x-topic --time -1

x-topic:0:0
x-topic:1:0
x-topic:2:0
x-topic:3:0
x-topic:4:0
x-topic:5:0
x-topic:6:0
x-topic:7:0
x-topic:8:0
x-topic:9:0
x-topic:10:0
x-topic:11:0

Send messages with the same key to the new topic: (ctrl-c to exit the producer when done)

# ./bin/kafka-console-producer.sh --broker-list kafka-1:19092 --topic x-topic --property "parse.key=true" --property "key.separator=:"

a-key:some-value
a-key:another-value
a-key:third-value

Inspect the offsets again, showing that each message has been sent to the same partition

# ./bin/kafka-run-class.sh kafka.tools.GetOffsetShell --broker-list kafka-1:19092 --topic x-topic --time -1

x-topic:0:0
x-topic:1:0
x-topic:2:0
x-topic:3:0
x-topic:4:0
x-topic:5:0
x-topic:6:0
x-topic:7:0
x-topic:8:0
x-topic:9:0
x-topic:10:0
x-topic:11:3   <-- all three messages on partition 11

Increase the number of partitions to 15

# ./bin/kafka-topics.sh --bootstrap-server kafka-1:19092 --topic x-topic --alter --partitions 15

And confirm the updated partition count

# ./bin/kafka-topics.sh --bootstrap-server kafka-1:19092 --describe --topic x-topic
Topic:x-topic	PartitionCount:15	ReplicationFactor:3	Configs:
	Topic: x-topic	Partition: 0	Leader: 1	Replicas: 1,2,3	Isr: 1,2,3
	Topic: x-topic	Partition: 1	Leader: 2	Replicas: 2,3,1	Isr: 2,3,1
	Topic: x-topic	Partition: 2	Leader: 3	Replicas: 3,1,2	Isr: 3,1,2
	Topic: x-topic	Partition: 3	Leader: 1	Replicas: 1,3,2	Isr: 1,3,2
	Topic: x-topic	Partition: 4	Leader: 2	Replicas: 2,1,3	Isr: 2,1,3
	Topic: x-topic	Partition: 5	Leader: 3	Replicas: 3,2,1	Isr: 3,2,1
	Topic: x-topic	Partition: 6	Leader: 1	Replicas: 1,2,3	Isr: 1,2,3
	Topic: x-topic	Partition: 7	Leader: 2	Replicas: 2,3,1	Isr: 2,3,1
	Topic: x-topic	Partition: 8	Leader: 3	Replicas: 3,1,2	Isr: 3,1,2
	Topic: x-topic	Partition: 9	Leader: 1	Replicas: 1,3,2	Isr: 1,3,2
	Topic: x-topic	Partition: 10	Leader: 2	Replicas: 2,1,3	Isr: 2,1,3
	Topic: x-topic	Partition: 11	Leader: 3	Replicas: 3,2,1	Isr: 3,2,1
	Topic: x-topic	Partition: 12	Leader: 1	Replicas: 1,3,2	Isr: 1,3,2
	Topic: x-topic	Partition: 13	Leader: 2	Replicas: 2,1,3	Isr: 2,1,3
	Topic: x-topic	Partition: 14	Leader: 3	Replicas: 3,2,1	Isr: 3,2,1

Send another three messages with the same key as previous:

# ./bin/kafka-console-producer.sh --broker-list kafka-1:19092 --topic x-topic --property "parse.key=true" --property "key.separator=:"
>a-key:post-repartition-value
>a-key:another-post-value
>a-key:one-more-value

And inspect the offsets again, expecting to see the same key written to a new partition

# ./bin/kafka-run-class.sh kafka.tools.GetOffsetShell --broker-list kafka-1:19092 --topic x-topic --time -1
x-topic:0:0
x-topic:1:0
x-topic:2:0
x-topic:3:0
x-topic:4:0
x-topic:5:3 <---- a-key messages after partition count updated
x-topic:6:0
x-topic:7:0
x-topic:8:0
x-topic:9:0
x-topic:10:0
x-topic:11:3 <---- original a-key messages
x-topic:12:0
x-topic:13:0
x-topic:14:0

Consume those messages (ctrl-c to exit the producer when done), noting:

  • individual partitions may be returned out of order (as below)
  • within a partition messages are ordered
# ./bin/kafka-console-consumer.sh --bootstrap-server kafka-1:19092 --topic x-topic --from-beginning --group x-consumer
post-repartition-value
another-post-value
one-more-value
some-value
another-value
third-value

Consuming again returns no messages, as offsets have been set and --from-beginning only applies where no offsets set

# ./bin/kafka-console-consumer.sh --bootstrap-server kafka-1:19092 --topic x-topic --group x-consumer
Processed a total of 0 messages

List the consumer groups

./bin/kafka-consumer-groups.sh --bootstrap-server kafka-1:19092 --list

x-consumer

Describe the current state of the 'x-consumer' consumer group

./bin/kafka-consumer-groups.sh --bootstrap-server kafka-1:19092 --group x-consumer --describe
Consumer group 'x-consumer' has no active members.

TOPIC           PARTITION  CURRENT-OFFSET  LOG-END-OFFSET  LAG             CONSUMER-ID     HOST            CLIENT-ID
x-topic         10         0               0               0               -               -               -
x-topic         11         3               3               0               -               -               -
x-topic         7          0               0               0               -               -               -
x-topic         9          0               0               0               -               -               -
x-topic         8          0               0               0               -               -               -
x-topic         12         0               0               0               -               -               -
x-topic         13         0               0               0               -               -               -
x-topic         2          0               0               0               -               -               -
x-topic         3          0               0               0               -               -               -
x-topic         14         0               0               0               -               -               -
x-topic         1          0               0               0               -               -               -
x-topic         4          0               0               0               -               -               -
x-topic         6          0               0               0               -               -               -
x-topic         5          3               3               0               -               -               -
x-topic         0          0               0               0               -               -               -

Because we have 'No active members' we can reset the offsets for this group if we like

./bin/kafka-consumer-groups.sh --bootstrap-server kafka-1:19092 --group x-consumer --reset-offsets --to-earliest --all-topics --execute

TOPIC                          PARTITION  NEW-OFFSET
x-topic                        10         0
x-topic                        11         0
x-topic                        7          0
x-topic                        9          0
x-topic                        8          0
x-topic                        12         0
x-topic                        13         0
x-topic                        2          0
x-topic                        3          0
x-topic                        14         0
x-topic                        1          0
x-topic                        4          0
x-topic                        6          0
x-topic                        5          0
x-topic                        0          0

Now consuming will cause us to re-consume previous messages again

# ./bin/kafka-console-consumer.sh --bootstrap-server kafka-1:19092 --topic x-topic --group x-consumer
post-repartition-value
another-post-value
one-more-value
some-value
another-value
third-value

Cleanup

docker ps
docker-compose rm

Copyright © 2019 Troy-West, Pty Ltd. MIT Licensed.