Kafka - Console consumer is stuck

Question

I created simple setup with 3 brokers and then created a simple topic and pushed messages using console producer. I tried to consume messages using console consumer with all the brokers alive and running, consumer is stuck.

Update #1

And one of the broker is doing a lot of processing with exceptions such as "NotEnoughReplicasException"

Logs

    org.apache.kafka.common.errors.NotEnoughReplicasException: The size of the current ISR Set(2) is insufficient to satisfy the min.isr re
quirement of 2 for partition __consumer_offsets-10                                                                                     
[2020-06-19 17:36:24,249] INFO [GroupCoordinator 2]: Preparing to rebalance group console-consumer-28937 in state PreparingRebalance wi
th old generation 4822 (__consumer_offsets-10) (reason: error when storing group assignment during SyncGroup (member: consumer-console-
[2020-06-19 17:36:24,305] INFO [GroupCoordinator 2]: Stabilized group console-consumer-28937 generation 4823 (__consumer_offsets-10) (k
afka.coordinator.group.GroupCoordinator)                                                                                               
23 (kafka.coordinator.group.GroupCoordinator)                                                                                          
[2020-06-19 17:36:24,306] ERROR [ReplicaManager broker=2] Error processing append operation on partition __consumer_offsets-10 (kafka.s
erver.ReplicaManager)                                                                                                                  
org.apache.kafka.common.errors.NotEnoughReplicasException: The size of the current ISR Set(2) is insufficient to satisfy the min.isr re
quirement of 2 for partition __consumer_offsets-10                                                                                     
[2020-06-19 17:36:24,307] INFO [GroupCoordinator 2]: Preparing to rebalance group console-consumer-28937 in state PreparingRebalance wi
th old generation 4823 (__consumer_offsets-10) (reason: error when storing group assignment during SyncGroup (member: consumer-console-
consumer-28937-1-21df21a9-3e11-4286-8252-3871633cf3bd)) (kafka.coordinator.group.GroupCoordinator)                                     
[2020-06-19 17:36:24,349] INFO [GroupCoordinator 2]: Stabilized group console-consumer-28937 generation 4824 (__consumer_offsets-10) (k
afka.coordinator.group.GroupCoordinator)                                                                                               
[2020-06-19 17:36:24,351] INFO [GroupCoordinator 2]: Assignment received from leader for group console-consumer-28937 for generation 48
[2020-06-19 17:36:24,351] ERROR [ReplicaManager broker=2] Error processing append operation on partition __consumer_offsets-10 (kafka.s

Facts about the Topic

Topic: new_topic        PartitionCount: 1       ReplicationFactor: 1    Configs:
    Topic: new_topic        Partition: 0    Leader: 3       Replicas: 3     Isr: 3

Answer 1

Fixed the issue by making min.insync.replicas = 1 ( the value was 2 while the issue is happening) as the topic in question new_topic had only replication factor 1 which is conflicting with min.insync.replicas .

However, the point which I didnt get quite so far is how min.insync.replicas is interfering with consumer path.