Identify the Active Controller In Kafka

What is Controller?

The Controller is one of the kafka broker's, usually behaves as a normal broker and having a controlling capability of managing partition state and replicas and reassignment of the partition.

How to get the current active controller?

Zookeeper is the storage of the kafka cluster, who elects the controller node either in the beginning of the cluster setup or when the controller node crashes. Here is the command to get the controller

• Shell command when installed on the host

zookeeper-shell 192.168.1.1:22181 get /controller

• When we are dealing with the docker container we can execute the above command in interactive mode as follows

# Connect to Zookeeper
docker run --net=host --rm confluentinc/cp-kafka:4.0.0 zookeeper-shell 192.168.1.1:22181

# Get the Controller
docker run --net=host --rm confluentinc/cp-kafka:4.0.0 zookeeper-shell 192.168.1.1:22181 get /controller

Note: 192.168.1.1 is the zookeeper IP