Free S90.03 sample questions

Correct answers: Service Reusability; Service Autonomy

The principle of Service Reusability, particularly through the application of a Standardized Service Contract, encourages the use of a canonical data model to ensure consistency and interoperability across the enterprise. However, this can conflict with Service Autonomy, which posits that services should have significant control over their own logic and resources. Forcing a service to conform to a rigid, enterprise-wide model can limit its ability to evolve independently and may require it to contain complex, non-native transformation logic, thus reducing its autonomy.

Correct answer: Saga

The Saga pattern is designed to manage data consistency across microservices in distributed transaction scenarios without relying on traditional locking mechanisms like two-phase commit (2PC). It sequences a series of local transactions. If any transaction fails, the saga executes a series of compensating transactions to revert the preceding transactions. This is ideal for the described scenario where a participating service does not support 2PC.

Correct answer: Technology Abstraction

Technology Abstraction is concerned with hiding the specific technologies used to implement a service. By exposing a data model that directly mirrors the CRM database schema, the service contract is tightly coupled to the underlying database technology (e.g., its table structure, column names, and data types). This violates Technology Abstraction because changes to the CRM database schema would directly impact service consumers.

Correct answer: False

This statement is false. Service Discoverability goes beyond simply publishing a technical endpoint. It requires supplementing services with communicative metadata that allows them to be effectively discovered and interpreted. This includes business-level information, quality-of-service details (SLAs), versioning information, and usage policies, not just the technical contract.

Correct answer: Service Agent, Data Transfer, and State Caching

This is the most comprehensive solution. A Service Agent runs on a schedule (e.g., every 15 minutes) to perform a Data Transfer from the mainframe batch system. The retrieved data is then stored in a cache (State Caching). The modern REST API (a Service Façade) then serves requests by querying this cache, providing a real-time experience to consumers while decoupling them from the legacy system's batch nature.

Correct answer: Service Discoverability

The core issue is that business-level stakeholders cannot find and understand the available services. Service Discoverability addresses this by requiring services to be supplemented with communicative metadata. This includes not just technical contracts but also business-centric descriptions, capabilities, and usage policies that enable both technical and non-technical users to effectively find, interpret, and compose services.

Correct answer: A reusable service that performs a multi-step customer credit verification by first checking internal records and then calling an external credit bureau service.

This is a perfect example of a sub-controller. It encapsulates a specific piece of composition logic (checking internal and external sources) that is reusable within larger processes (like 'New Customer Onboarding' or 'Loan Application'). It consumes other services (internal records, external bureau) and is itself designed to be composed by a parent controller service.

Correct answer: Sidecar

The Sidecar pattern involves deploying components of an application into a separate process or container to provide isolation and encapsulation. In a Kubernetes context, a sidecar is a container that runs alongside the main application container in the same Pod. This is commonly used for cross-cutting concerns like logging, monitoring, security, or as part of a service mesh.

Correct answer: API Gateway

An API Gateway is a server that acts as a single entry point into the system. It is responsible for request routing, composition, and protocol translation. It can also handle cross-cutting concerns like authentication, SSL termination, and rate limiting. This pattern is ideal for microservice architectures as it decouples clients from the internal service topology and provides a tailored API for each client type.

Correct answer: Implement a Service Façade layer that exposes standardized REST/JSON APIs. This layer uses Protocol Bridging to communicate with the mainframe via its socket protocol and applies the Data Model Transformation pattern to convert between the canonical and mainframe data formats.

This solution correctly addresses all requirements. The Service Façade provides the standardized REST/JSON interface (Req 1). It decouples partners from the mainframe (Req 2). Protocol Bridging is the specific pattern for translating between the modern HTTP and legacy socket protocols without modifying the mainframe (Req 3). Data Model Transformation handles the conversion to a canonical model (Req 4). This is the most complete and pattern-oriented SOA solution.