SOA Certified Professional C90-03A real exam prep : Cloud Technology Lab

Cloud Service Consumer A invokes Cloud Service A from Cloud X (owned by Cloud Provider X) (1). To fulfill the request from Cloud Service Consumer A, Cloud Service A needs to invoke Cloud Service B that resides on Cloud Y (owned by Cloud Provider Y) (2). After completing its processing, Cloud Service B sends a response to Cloud Service A (3). Cloud Service A verifies the response and then finally sends its response to Cloud Service Consumer A (4).

The guaranteed availability of the Cloud Service A implementation is 95% and the guaranteed availability of the Cloud Service B implementation is 95%. Which of the following statements accurately describes the actual availability that Cloud Service Consumer A can receive based on the described scenario?

• A. As a result of the dependency formed by Cloud Service Aon Cloud Service B,the combined availability decreases significantly as follows:
  (0.95 X 0.95) - 0.1 = 0.8025 or 80.25%
• B. Because Cloud Service Consumer A's response message is processed by two separate cloud
  services, the combined availability increases as follows:
  1 - (1 - 0.95) X (1 - 0.95) = 0.9975 or 99.75%
• C. Cloud Service Consumer A benefits from redundant cloud service implementations, thereby
  increasing the guaranteed availability as follows:
  1 - (1 - (0.95 - 0.1))X (1 - (0.95 - 0.1)) = 0.9775 or 97.75%
• D. Because Cloud Service A acts as both a cloud service and cloud service consumer in order to
  process Cloud Service Consumer B's request message, Cloud Service A forms a dependency on
  Cloud Service B. As a result, the combined availability decreases, as follows:
  0.95 X 0.95 = 0.9025 or 90.25%

Organization A has been expanding and, as a result, is outgrowing the processing capacity of its on-premise Service A implementation. It is determined that this is due to usage thresholds of Service A and complex data processing limitations in Database A. The diagram depicts Organization A's current on-premise environment, where Service Consumers A. B and C attempt to access Service A at the same time. Service Consumer A successfully accesses Service A, which then successfully retrieves the requested data (1). Service Consumer B successfully accesses Service A, but due to the complex data structure, the request for the data times out and fails (2). Finally, Service Consumer C attempts to access Service A, but is rejected because Service A is unable to accept more concurrent requests.

Organization A is required to continue using its on-premise Service A implementation, with the exception of Database A, which does not need to remain on-premise. Database A is dedicated to Service A and is comprised of relational data.
Which of the following statements provides a solution that uses cloud-based IT resources to solve the performance limitations of Service A and Database A?

• A. None of the above.
• B. A cloud balancing solution can be implemented within the public cloud, whereby a redundant Cloud Service A implementation is established. Cloud Service A becomes the first point of contact for Service Consumers A, B and C (thereby turning them into Cloud Service ConsumersA. B and C). Upon reaching its usage threshold (which will be higher than the on-premise Service A), Cloud Service A automatically routes usage requests to Service A. The resource replication mechanism is implemented within the cloud to establish a replicated Database A that can further be used to load balance data access requests from Cloud Service A or Service A.
• C. The virtual server and resource replication mechanisms can be implemented to replicate Service A and Database A across both on-premise and cloud environments. This enables on-demand usage in that requests sent by Service Consumers A, B and C will automatically be redirected to the replicated service and/or database. As a result, Service A' s usage thresholds will no longer result in rejected requests and Database A' s processing limitations will no longer result in failed data access attempts.
• D. Automated scaling listener mechanisms can be implemented in both the on-premise and cloud environments. Using built-in resiliency features, these service agents can be configured to coordinate the routing of messages between the on-premise Service A implementation and a redundant Cloud Service A implementation. This dynamic functionality can avoid service usage thresholds in both Service A and Cloud Service A.

Cloud Consumer A (the organization that owns Cloud Service Consumer A) needs regular access to an external, cloud-based Weather Service that provides up-to-date weather forecast information. Cloud Providers X, Y and Z are competing public cloud providers, each offering a Weather Service with the features required by Cloud Consumer A.

Based on the provided statistics, which cloud provider can offer a Weather Service with the least amount of projected downtime?

• A. Any of the three cloud providers, because their availability ratings are identical.
• B. Cloud Provider Y
• C. Cloud Provider Z
• D. Cloud Provider X