Industrial fault description:

A service is slowing down and returns error finally.
Endless recursive requests of a microservice are caused by SQL errors of another dependent microservice.


TrainTicket replicated fault description:

In out train ticket system, we replicate this fault in voucher service.
The SQL arg in voucher service is something wrong, make the request fail.
When the request is fail, the host service will send another request.
After many retries, we will receive a timeout error finally.