What is the bootstrap.servers configuration on a Kafka client?

bootstrap.servers is a client setting (producer, consumer, admin client): a comma-separated list of host:port pairs, host1:port1,host2:port2, used to establish the initial connection to the cluster. The client uses it only to discover the full set of brokers: it connects to a listed broker, fetches cluster metadata (which brokers are alive and which broker is the leader of each partition), and then talks directly to the brokers it needs, using the addresses the brokers publish through advertised.listeners. Listing more than one broker is recommended for resilience, but the list does not have to include every broker. Example: bootstrap.servers=broker1:9092,broker2:9092,broker3:9092

Expected key concepts: bootstrap.servers, host:port, comma-separated, initial connection, discover, cluster metadata, leader, advertised.listeners, resilience, brokers