I want to build a HA Kafka cluster, where the cluster needs to span 2 availability zones.
I want to be able to continue to read and write to a topic, even if all the brokers in an AZ go down.
If I have at least 2 brokers in each AZ, a replication factor of 3, min ISR of 2 and acks set to All, then I think that a producer write will be acked when one other broker other than the leader also acks the write. Does the rack aware algorithm enforce that the ISR must be located in the other AZ? The docs just mention replicas, not the ISR.
Will this enable me to continue reading and writing in the event of the loss of an AZ? If not, what is needed to achieve this?