Given the trend around microservices, it has become mandatory to be able to follow a transaction across multiple microservices. Spring Cloud Sleuth is such a distributed tracing system fully integrated into the Spring Boot ecosystem. By adding the spring-cloud-starter-sleuth into a project’s POM, it instantly becomes Sleuth-enabled and every standard log call automatically adds additional data, such as spanId and traceId to the usual data. 2016-11-25 19:05:53.221 INFO [demo-app,b4d33156