What is a Consumer Group in Kafka? When is it not necessary to combine two consumers into one group?

Consumer Group in Kafka is a group of consumers that jointly read data from topics. Each partition of a topic is distributed among consumers within the group so that each partition is read by only one consumer from the group. This allows scaling message processing and load balancing.

When it is not necessary to combine two consumers into one group:

• If you want both consumers to receive all messages from the topic (for example, different services processing the same data independently). Then each should have its own Consumer Group ID.
• If the consumers perform different tasks and should not compete for messages.

Example: two microservices listening to the same topic and doing different things — they need different groups so that each receives the full stream of messages.