Alter Kafka topic partition

Steps to change Kafka Partitions

1. Create topic demo_topic13 with partitions 6

/opt/kafka/bin/kafka-topics.sh --create --zookeeper localhost:2181 --replication-factor 3 --partitions 6 --topic demo_topic13

2. Describe topic before alter topic
[root@node1 ~]# /opt/kafka/bin/kafka-topics.sh --describe --zookeeper localhost:2181 --topic
demo_topic13
Topic:demo_topic13      PartitionCount:6        ReplicationFactor:2     Configs:
        Topic: demo_topic13     Partition: 0    Leader: 3297    Replicas: 3297,2812     Isr: 3297,2812
        Topic: demo_topic13     Partition: 1    Leader: 2812    Replicas: 2812,3297     Isr: 2812,3297
        Topic: demo_topic13     Partition: 2    Leader: 3297    Replicas: 3297,2812     Isr: 3297,2812
        Topic: demo_topic13     Partition: 3    Leader: 2812    Replicas: 2812,3297     Isr: 2812,3297
        Topic: demo_topic13     Partition: 4    Leader: 3297    Replicas: 3297,2812     Isr: 3297,2812
        Topic: demo_topic13     Partition: 5    Leader: 2812    Replicas: 2812,3297     Isr: 2812,3297

3. alter partition with 7 (note: you con't decrease  partitions)
[root@node1 ~]# /opt/kafka/bin/kafka-topics.sh --alter --zookeeper localhost:2181 --topic demo_topic13 --partitions 7
WARNING: If partitions are increased for a topic that has a key, the partition logic or ordering of the messages will be affected
Adding partitions succeeded!

4. describe topic and check

[root@node1 ~]# /opt/kafka/bin/kafka-topics.sh --describe --zookeeper localhost:2181 --topic demo_topic13
Topic:demo_topic13      PartitionCount:7        ReplicationFactor:2     Configs:
        Topic: demo_topic13     Partition: 0    Leader: 3297    Replicas: 3297,2812     Isr: 3297,2812
        Topic: demo_topic13     Partition: 1    Leader: 2812    Replicas: 2812,3297     Isr: 2812,3297
        Topic: demo_topic13     Partition: 2    Leader: 3297    Replicas: 3297,2812     Isr: 3297,2812
        Topic: demo_topic13     Partition: 3    Leader: 2812    Replicas: 2812,3297     Isr: 2812,3297
        Topic: demo_topic13     Partition: 4    Leader: 3297    Replicas: 3297,2812     Isr: 3297,2812
        Topic: demo_topic13     Partition: 5    Leader: 2812    Replicas: 2812,3297     Isr: 2812,3297
        Topic: demo_topic13     Partition: 6    Leader: 3297    Replicas: 3297,2812     Isr: 3297,2812