Summary

Prior to Istio, the common solution in the Spring ecosystem to issues of service discovery, resilience, load balancing was Spring Cloud. Spring Cloud consists of multiple projects that provide dependencies that developers add to their applications to help them deal with issues of client-side load-balancing, retries, circuit-breaking, service discovery and so on.

In spring-petclinic-istio, those dependencies have been removed. What remains as dependencies inside each service are what you'd expect to find:

• Spring Boot and actuator are the foundation of modern Spring applications.
• Spring Data JPA and the mysql connector for database access.
• Micrometer for exposing application metrics via a Prometheus endpoint.
• Micrometer-tracing for propagating trace headers through these applications.