Hey Alexander,

• Yes, but when call to Fronting Kafka fails, it sends the messages to Redis, so we implemented our own logic with hystrix circuit breaker
• Yes, that is very unlikely, but the writes to that Kafka can fail due to multiple reasons, in that scenario the consumer lag on the fronting worker will keep on increasing, and the Redis fallback is for the scenario if fronting Kafka is having some issue
• We actually publish an envelop to the fronting rest which forwards it to a generic topic in fronting Kafka, this worker then extracts the topic name from that envelop and pushes it to corresponding topic on Mainstream Kafka